Soviet Atomic Energy - Vol. 34, No. 2

Body: Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 ok7 Russian Original Vol. 34, No. 2, February, 1973 August, 1973 SATEAZ 34(2) 101-192 (1973) ? SOVIET ATOMIC ENERGY ATOMHAF1 3HEFTWA (ATOMNAYA iNERGIYA) TRANSLATED FROM RUSSIAN CONSULTANTS BUREAU, NEW YORK Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 SOVIET ATOMIC ENERGY Soviet At .,Energy isa cover-to-cover translation of Atomnaya , Energiya, a publication Of the Academy Of Sciences of the USSR. An arrangement with'Mezhdunarodnaya Kniga, the Soviet book export agency, makes available both advance copies of the Rus- sian journal and original glossy photographs and artwork. This sertes to decrease the necessary time lag between: publication of the original and publication 64 the translation ,end helps to im- prove the quality of the latter. The translation began with-the first issue' of the Russian joUrnaL \Editorial Board of Atomnaya nergiya: Editor: M.' D. MillicnshCtiikov , , Deputy Director- !. V. Kurchatov Institute of Atomic Energy Academy of Sciences of the USSR Moscow, pssR ? Associate Editors: N. A. Kolokol'tsov N. A. Vlasov A. A. Bochvar' N. A. Dollezhal' V. S. Fursov 1:.N. Golgvin V. F. Kalinin A. K. K.resin A. I. Leipuntlii A. P. Zefirov V. V. Matve,ev 1.4 G: Meshcheryakov P. N. Patel . V. B. Shevchenko :D. L. Simonenko V. I. Smirnov A. P: Vinogradov ? Copyright?1973 Consultants Bureau, New York, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N.Y. 10,p11. All rights reserved. No article contained herein maY be reproduced for any purpose whatsoever Without permission of the publishers. Consultants Bureau" Journals appear about six months after the -publication of the original Russian issue. For bibliographic accuracy, the English issue published by Consultants Bureau carries the, same number and date as the original Russian '6.om which It was translated. For example, ?ussian Issue Published In Decem- ber will appear in a Consultants Bureau English translation about the following June, but the translatiOn issue will carry,the December date. When ordering any v,olume or particular ,issue of a Consultants Bureau_journal, please specify the date and, where applicable, the volume and issue numbers of the original Russian. The material you Will receive will be a translation, of that Russian volume or issue. Subsariptsion , $80 per'volume (6 Issues) 2 volumes per year . (Add $5 for orders outside the United States and Caneide.) CONSULTANTS BUREAU,?NEWYORK AND LONDON Single Issue: $30 Single Article: $15 _ avis '227 West 17th Street D Heuse 8 Scrubs Lane New York, New York 10011 v Harlesden, NW1D 6SE England Published monthly. Second-clais?postage Paid at Jamaica, New York 11431. Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 SOVIET ATOMIC ENERGY A translation of Atomnaya Energiyp. Augast, 1973 Volume 34, Number 2 February, 1973 Discrete Monitoring of the Power Distribution in the Active Zones of Nuclear Reactors ? I. Ya. Emel'yanov, V. N. Vetyukov,i L. V. Konstantinov, - CONTENTS As A 4. Engl./Russ. V. G. Nazaryan, I. K. Pavlov, and V. V. Postnikov 101 75 Deposits on VK-50 Fuel Elements ? A. I. Zabelin, B. V. Pshenichnikov, and T. Svyatysheva 107 81 Some Physical and Mechanical Properties of Uranium? Zirconium Alloys at Low Temperatures ? G. B. Fedorov, ? M. T. Zuev, E. A. Smirnov, and A. E. KissiP 111 85 Phase Structure of Niobium-Based Alloys in the System Niobium?Tungsten ?Zirconium?Carbon ? E. M. Savitskii and K. N. Ivanova 115 89 Experimental Fitting of Data Relating to the Irradiation of Graphite in Reactors to a Universal Scale of Damage-Inducing Fast Neutron Flux ? V. I. Klimenkov and V. G. Dvoretskii 120 93 Unified Industrial System of Nuclear Instruments for Instrumental Activation Analysis ? B. G. Egiazarov, V. V. Matveev, and Yu. P. Selidyakov 124 97 RE VIEWS Nuclear Spectroscopy at the Radium Institute ? B. S. Dzhelepov, N. N. Zhukovskii, R. B. Ivanov, and V. P. Prikhodtseva 132 105 BOOK REVIEWS New Books 137 109 ABSTRACTS Optimization of Heat Removal in a Nuclear-Reactor Channel as a Problem in Game Theory - V. S. Ermakov and G. I. Zaluzhnyi 140 111 Formulation of Boundary Condition in the Method of Subgroups ? M. N. Nikolaev and D. A. Usikov 141 112 Effect of the State of the Zirconium Surface on the Structure and Protective Properties of Oxide Films Forming in a Corrosive 'Environment ? I. I. Korobkov 142 112 Time Selection in Activation Analysis ? G. S. Vozzhenikov 143 113 Characteristics of Point Activation Measurements Made in Boreholes with a Controlled Neutron Source ? V. V. Streltchenko and K. I. Yakubson 144 114 Spectral-Angular Distribution of Fast Neutrons Emerging from Different Sections of the Surface of an Iron Reflector ? D. B. Pozdneev and M. A. Faddeev 145 114 LETTERS TO THE EDITOR The Free Energy of Formation of Uranyl Ions at High Temperatures ? R. P. Rafal'skii 146,1' 115 Experimental Data on the Thermal Neutron Spectrum in Water-Moderated Reactors ? S. S. Lomakin and G. G. Panfilov 149 117 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 CONTENTS Evaluation of Neutron Sensitivity for a Personnel Dosimeter Using Type-K Nuclear Emulsion - M. G. Gelev, M. M. Komochkov, I. T. Mishev, (continued) Engl./Russ. and M. I. Salatskaya f52 118 Evaluation of'Silicon Semiconductor Detector Efficiency for 0.661 and 1.25 MEV Gamma Rays - M. L. Gordin, K. R. Pater-Razumovskii, and F. V. Virnik 156 121 Detector Characteristics of a Silicon Carbide Detector Prepared by the Diffusion of Beryllium - V. A. Tikhomirova, 0. P. Fedoseeva, and G. F. Kholuyarov . . 158 122 Radiation Stability of Scintiliating Plastics - E. D. Beregovenko, V. M. Gorbachev, and N. A. Uvarov 160 124 A Low-Background Gamma Spectrometer - Yu. A. Surkov and 0. P. Sobornov . . . . 162 125 A Digital Recording Method for the Results of Radiometric Measurements -V. P. Bovin, K. M. Volodin, A. A. Eremin, and A. A. Lintser 165 127 Gamma-Ray Buildup Factor for a Spherical Shield, - V. A. Zharkov, A. A. Chudotvorov, and A. F. Kolesnikov 167 128 Fluorescence of Air Under the Action of Relativistic Electrons - V. D. Volovik, V. I. -Kobizskoi, V. V. Petrenko, G. F. Popov, and G. L. Fursov 170 130 Focusing of Superconducting Solenoids in High-Energy Linear Proton Accelerators - B. I. Bondarev, V. V. Kushin, B. P. Murin, L. Yu. Solov'ev, and A. P. Fedotov 172 131 Measurement of the Energy Distributions of the Fragments Derived from the Fission of Preactinide Nuclei by Alpha Particles, Using the "Track Method" - M. G. Itkis, V. N. Okolovich, A. F. Pavlov, and G. Ya. Rus'kin21 175 133 The Average Number of Neutrons Emitted in the Spontaneous Fission of Cm , cm24e, and c m248 V. V. Golushko, K. D. Zhuravlev, Yu. S. Zamyatnin, N. I. Kroshkin and V. N. Nefedov 178 135 COMECON NEWS Collaboration Daybook 180 137 NEWS The All-Union Conference on the Use of Radiation Techniques in Agriculture - D. A. Kaushanskii 183 139 Fifth All-Union Conference on the Physics of Electron and Atom Collisions - V. B. Leonas 185 140 Soviet -Swedish Symposium on the Physics of Thermal and Fast Reactors - I. D. Rakhitin 187 141 BRIEF COMMUNICATIONS 190 143 The Russian press date (podpisano k pechati) of this issue was 1/31/1973. ' Publication therefore did not occur prior to this date, but must be assumed to have taken place reasonably soon thereafter. Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 DISCRETE MONITORING OF THE POWER DISTRIBUTION IN THE ACTIVE ZONES OF NUCLEAR REACTORS I. Ya. Emel'yanov, V. N. Vetyukov, L. V. Konstantinov, V. G. Nazaryan, I. K. Pavlov, and V. V. Postnikov UDC 621.039.564.2 The achievement of precise and reliable monitoring of the power distribution in a reactor is a neces- sary condition for the economically effective and safe use of a powerful nuclear installation. At the present time it is a generally accepted practice to use sensors discretely sited within the active zone [1]. An anal- ysis of signals arising from the sensors within the reactor by means of an information store and computer facilitates operative monitoring of the precritical thermal-loading reserve of every fuel element, and hence helps in optimizing the fields of energy evolution, with a view to increasing the power and heat-technologi- cal reliability of the reactor and also the mean integrated power development of the fuel charge. Despite the fact that an optimization of the methods of mathematically analyzing discrete measure- ments of power distribution inside the reactor would provide a great increase in monitoring accuracy, and hence in the accessible power potential of the fuel (or the heat-technological reliability of the reactor), in- sufficient attention has as yet been paid to this problem in the literature. In the present investigation we studied two methods of discretely monitoring the energy distribution: empirical and experimental-computing. The first method constitutes an engineer's solution of the prob- lem, and is based on the use of simple empirical relationships obtained in experiments relating to the starting and initial period of use of the fundamental reactor of the type in question; the second method is based on the simultaneous use of the results of a physical calculation and discrete measurements of the power distribution. The use of both methods is illustrated by reference to the Beloyarsk Nuclear Power Station. The empirical method of monitoring the power distribution W(r) is based on the concepts of a macro- scopic field Wm(r) and a field microstructure co(r) [1-3]. The problem of discrete monitoring in this case reduces to a determination of the values of the macrofield at the sensor sites: TABLE 1. Comparison between Various Interpolation Methods Interpolation procedure Empirical method Experimental-computer method A B 4v 1 `,%)2 A B 41 eV Plane interpolation 0,380 0,333 45,35 0,309 0,333 20,03 Method of least squares 0,398 0,258 47,36 0,345 0,258 22,11 Interpolation by Lagrange polyno- mials m=1, /14 =4 0,353 0,250 42,04 0,280 0,250 18,04 m=3, Ars =16 0,318 0,409 38,29 0,258 0,409 17,02 m=5, Ar, =36 0,320 0,498 38,72 0,283 0,498 18,78 m=7, N't =64 0,490 0,115 57,83 0,381 0,115 24,04 Statistical interpolation n=N5 =4 0,334 0,356 40,04 0,276 0,352 18,02 n= Ns =16 0,315 0,402 37,92 0,251 0,397 16,56 n =1Vs =36 0,315 0,404 37,92 0,252 0,360 16,54 Translated from Atomnaya gnergiya, Vol. 34, No. 2, pp. 75-80, February, 1973. Original article submitted April 20, 1972; revision submitted August 28, 1972. O 1973 Consultants Bureau, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article cannot be reproduced for any purpose whatsoever without permission of the publisher. A copy of this article is available from the publisher for $15.00. 101 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 az) 40 20 0005 0,10 0,15 Fig. 1 ?\0.. . 0. 45 1,5 , Fig. 2 Fig. 1. Relative correlation functions of the distribution W(r) obtainedby measure- ments in the reactor of the second unit of the Beloyarsk Nuclear Power Station, using small-scale fission chambers at "zero" power for the whole active zone (0) and for the central part of the latter (0). Fig. 2. Relative correlation functions of the distribution 170(r) for the reactor in the second unit of the Beloyarsk Nuclear Power Station obtained by fission chambers at "zero" power (0) and derived from the residual activity of the fuel channels for the central part of the shut-down reactor (0). b . )?.*"...d - c 0,20 Wris Fig. 3. Dependence of and kri on 1/Arn5 for the reactor of the second unit in Beloyarsk Nuclear Power Station, obtained by the empirical (a, b) and ex- perimental-computing (c, d) methods using Eq. (4) (a, c) and by direct cal- culation [4] (b, d) from the results of experiments at "zero" power. Wm (r) ((:)) , (1) the interpolation of these values over the whole reactor, and the subsequent introduction of corrections allowing for the microstructure of the power distribution for every fuel ele- ment [3]. We note that the direct interpolation of the dis- tribution W(r) rather than Wm(r) leads to a considerably greater error in monitoring the power distribution. The Wm(r) distribution may, in general, be formally considered as a nonuniform, random distribution with a varying mathematical expectancy, dispersion, etc., since in addition to the general variation in Wm(r) due to the di- mensions of the reactor and the averaged distribution of the fuel load and control units, there are also purely random deviations associated with technological scatter in the dis- position of the fuel elements and absorption units, and also local quasirandom deviations associated with various local- ized inhomogeneities, which cannot be completely taken into account in the manner represented by Eq. (1). In view of all this, we employed the elementary concepts of the theory of random functions [4], in addition to other methods [2, 3], when choosing a method of interpolating the macrofield and analyzing the results obtained. In order to avoid the difficulties arising from a direct interpolation of nonuniform random distribu- tions, we used the operation of macrofield centering [5] Wm (r )= W. (rs)-117-,,? (rs), (2) where Wm(rs) is the centered random distribution, Wm(r5) is the mathematical expectancy of the macro- field, constituting the result of approximating the discretely measured distribution Wm(rs). By way of expressions approximating the values of Wm (rs) in the sensor sites for the two-dimensional case, we considered a series of Bessel functions and trigonometrical functions, a polynomial of the second degree, and a unidimensional radial distribution, obtained by mathematical smoothing of the measured quantities. In the absence of sensors on the periphery of the reactor, Wm(r) may be derived by "sewing together" the distribution in the central region and the distribution on the periphery of the active zone determined experimentally or by physical calculations. 102 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 36 35 34 33 32 31 SO 29 28 27 26 25 24 23 22 21 20 .19 18 1 2 3 S S. 8 g 10 11 12 13 14 15 16 17 18 19 15,5 12,7 :2,1:142 12,4 18,0 18,0 21,7 5,542,12413,1 148 247 14,0 16,5 144 14,4 24,6 149 19,5 24515,2 r 2,1 14,7 243 24,0 22,315,5 r r k2,1 4 13,22,114,820,2 13,5 15,0 18,9 23,7 25,7 23,9 19,0 15,3 25,7 19,0 14,0 16,1 19,0 19,3 19,0 21,1 24,7 242 24,7 21,3 19,6 25,7 23,2 244 16,3 13,8 16,3 16,6 14,9 18,7 24 24,7 23,2 18,8 15,3 16,7 18,4 19,4 14,6p,2,1: 13,4 13,41.3=21,4 20,3 15,0r2,12: 16,52,114,8 18,913,4 14,7 148 16,6 14,4 16,5 149 15,0 13,113,2 16,3 23,113,8 18,0 18,6 13,8 15,9 18,4 140 19,2 16,0 13,5 14,6 14,3 145 20,0 19,6 19,4 145 18,2 14,5 17,8 16,4 14,2 16,5 r 1 12,1,15,0 14,7 18,6 21,0 24,0 24,5 29,0 h2,11:14,5 18,1 14,22,0310,42,0414,3 17,6 13,8:20,14,4 18,9 141 20,3 24,2 30,4 14,9 142 18,4 15,9 13,4 14,3'14,116,4 16,0 12,1 12,2 16,7 19,2 144 15,3 21,0 29,4 19,3 19,3 141 13,715,2 13,118,4 19,0 14,53,03413,5 148 18,0 14,03,03)7,5 245 18,0 19,1 15,0,0412,0 14,0 144 20,0 " 17,5 14,4 16,3 16,3 13,8 14,014,2 20,5 248 1 2,13415,2 240 147 r- I 13,4 11,6 i,03,15,0 20,0 20,0 18,2 18,0 14,1 r 1 Z,05?13,2 145 23,0 346 18,0 20,4 23,0 21,2 16,2 12,0 12,3 17,4 20,218,0 14,516,4 13,0 14,1 14,0 14,2 20,6 30,0 244 240 28,0 24,3 142:20;,14,7 21,0 21,5 1402,1;415,1 242 240140 2,12,18,030,2 Fig. 4. Distribution of o-2(%)2 with respect to the fuel channels of one quadrant of the active zone in the second unit of the Beloyarsk Nuclear Power Station (shaded corners indicate channels containing sensors). The latter two means of approximation were the most convenient for the practical analysis of discrete measurements in a computer. It should be noted that the correctness of our choice of approximating ex- pression may be confirmed by finding whether the discrete monitoring errors derived from correlation analysis agree (see Eq. (4)), and also by comparing the calculated and measured power distributions [3]. In accordance with (2), the unknown distribution of the macrofield over the reactor was determined as the sum of Wm(r) and the interpolated distribution of Taking a square lattice of sensors as an example, we studied four methods of interpolating Wm(r): 1) plane interpolation in which the value of Wm is determined for each fuel channel as the z coordinate of the plane drawn through the values of Wm(r) for the three nearest sensors; 2) successive approximation (by the method of least squares) of the values of Wm(r) derived from sensors separated distances of no more thatn -1/6 of the reactor diameter by a polynomial of the second degree; 3) successive interpolation along the x and y axes by Lagrange polynomials of degree m, equal to 1, 3, 5, 7; 4) statistical interpolation [4] based on the theory of random functions. In a number of cases the interpolation indicated in 1)-3) may be carried out directly for the values of Wm(r) without serious loss of accuracy, without first carrying out the centering operation. The essence of the latter interpolation (proposed earlier [6] for unidimensional stationary random processes) lies in finding the unknown coefficients ai of the interpolation series 0 7'7 0 W?,(r)= aiWmi (ri) i=1 from the minimum interpolation error of the spatial distribution of Wm(r). In Eq. (3), n is the order of interpolation, equal to the chosen number of neighboring sensors measuring the quantities Wi(r) used in calculating Wm(r). Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 (3) 103 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 The dispersion of the interpolation error for an arbitrary fuel channel may be expressed as the dis- persion of a linear combination of random functions [6]: cr4-I=Acqq+Bas n n A=1+ E ajaipij -2 E (IA; 1=1 5=1 i=t B= E 1=1 where al is the dispersion of the random field Wm? ? Gr 2 is the dispersion of the sensor error pii = Kw( s -r?I)/o-2 is the normalized value of the correlation function Kw(Iri- 91) of the random field Wm(r) J W Kw(lr-ri I) Pt aw 2 ? (4) Equating to zero the derivatives of o-2w, with respect to each of the coefficients ai, we obtain a system of equations for finding the values of these: (1 + 4 /4) cri + P12a2 ? ? ? ? + Pinan = Pi; 1. P21a1+ (I ? qicctiv) a2+ ? ? ? + P2nan = p2; Pniai+Pn2a2+ ? ? ? ?(+ crs2/crig) an= Pn? (5) In Eq. (4) the errors of the sensors are regarded as mutallyuncorrelatedquantities, and the dispersion of the random field cr 2 =KW (0) is taken as constant over the active zone. If the latter condition is not sat- isfied, it is essential to center Wm(r) with respect to the dispersion [5]. The correlation functions Kw(r) of the distribution of Wm(r), like the coefficients characterizing the microstructure of the power distribution, may be obtained by experiments or physical calculations. Figure 1 illustrates the relative correlation functions PW(T) for the centered power macrofield of the fuel channels in the reactor of the second unit of Beloyarsk Nuclear Power Station. The pw(T) curves determined for different parts of the reactor lie close to one another in the initial section (T < 1.0-1.2 m), which is of practical interest in the processing of the discrete measurements. Calculations showed that in ads case the coefficients Pi approached zero for Ir-r > 1.2-1.4 m. Thus the most appropriate order of statistical interpolation n is determined by the number of sensors lying within this distance of the fuel channels. An advantage of statistical interpolation lies in the fact that exactly the same computing method may be used for both interpolation and extrapolation, as well as for refining the measurements at the sensor sites by reference to the readings of neighboring sensors. The foregoing procedures for interpolating the centered macrofield on the empirical principle are compared in Table 1 for a fuel channel lying in the center of a rectangular lattice of Ns sensors, by com- paring the values of cr2w calculated from Eq. (4) and pw(r) illustrated in Fig. 1. The experimental-computing method of monitoring the power distribution is based (as in [7]) on determining a quantity V(r) for each sensor, this being the ratio of the measured signal to the signal de- rived from a physical calculation of the neutron flux or power distribution. The relative distribution of W(r) was determined as the product of the power distribution obtained from the physical calculation and the distribution of V(r) [1, 4]. The absolute value of the power distribution was determined, as in the empir- ical method, by normalizing the relative distribution to the thermal power of the reactor. In order to optimize the experimental-computing method, we studied various ways of interpolating the distribution V(r). An analysis of many calculated and experimental power distribution showed that V(r) = V(r)-V(r) might be considered as a homogeneous random distribution. The relative correlation functions 104 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 PV(T) = Kv(r)/Kv (0) of the distribution V(r) shown in Fig. 2, corresponding to two different states of the reactor in the second unit of the Beloyarsk Nuclear Power Station, are similar to one another in the range T < 0.5 m. It should be noted that the distances T at which the correlation functions of the radial-azimuthal distributions of Wm(r) and V(r) fall by a factor of two are practically identical, and amount to 0.08-0.1 of the radius of the active zone for the Beloyarsk reactors. This is evidently associated with the fact that the relative ranges of propagation of the distortions introduced into the power distribution by random local perturbations in the active zones of these reactors are identical. The results of our investigation into the four methods of interpolating the V(r) distribution under the conditions indicated when considering the empirical method are shown in Table 1. The values of 0.2v were calculated from (4) using the correlation function of Fig. 2. The tabulated values of the mean square errors o- and o-VI for the various methods of interpolation and the values of A and B for statistical WI interpolation correspond to us = 1.5%; = 10.8% and o-v = 7.9%. It follows from an analysis of the tabulated data that the best accuracy is given by statistical inter- polation in both the empirical and the experimental -computing methods. The latter method gives a smaller error in discrete monitoring as compared with the empirical, but it requires regular physical calculations of the power distribution on a fairly powerful (usually external) electronic computer. The frequency of these calculations may be reduced with the aid of the station's own computer by introducing corrections based on Eqs. (1) and (2) to allow for slight changes in the positions of the control devices and the charging of the reactor. A reliable estimation of the error committed in the discrete monitoring of the power distribution during the service life of the reactor is of particular importance for choosing safe and efficient operating conditions for the fuel channels. In order to verify the validity of the method of estimating the monitoring accuracy, we compared the values of a. 2 averaged over the reactor obtained in accordance with (4) and by comparing [3] the interpolated and measured values (Fig. 3). The dependence of 0" 2 on tins, which is proportional to the spacing in the lattice of ns sensors uniformly distributed in the reactor of the second unit of the Beloyarsk Nuclear Power Station, is closely described by the linear relationship generally characteristic of such cases. The re- sults of Fig. 3 demonstrate the satisfactory accuracy of the method of computing u based on Eq. (4). It should be noted that the results of Figs. 3 and 4 and Table 1 correspond to measurements of the power of individual fuel elements in the fuel channels made during the physical initiation period, using a charge of considerable inhomogeneity. During actual serivce, the errors in the two methods were in general 1.5-2.0 times lower for the fuel channels. As an example of the calculation of o- for individual fuel channels, Figure 4 illustrates the distribution of o-2 over part of the active zone of the reactor in the second unit of the Beloyarsk Nuclear Power Sta- tion, corresponding to statistical interpolation in the empirical method. A comparison of the experimental and calculated values shows that the error in the discrete monitor- ing obeys a normal distribution law. The reliability which is essential for the discrete monitoring of the power distribution can only be achieved if measures are taken to eliminate coarse errors (faults or oversights) in the measurements and general (systematic) failures associated with maladjustments of the sensors, breakdown of the computer, operator errors, etc. The power distribution should therefore be monitored by at least two different methods. Mistakes in measurements committed in, for example, the Beloyarsk Nuclear Power Station, may then be revealed by applying statistical-"unacceptability" criteria to the relative differences in the distributions obtained by the different methods and analyzing these on a computer. In the same way, it is desirable to compare V(r) or W(r) over a specific range, and at the symmetrical points of the active zone, and also to compare analogous quantities measured at a specific point over a certain time interval. The methods of discrete monitoring of multidimensional distributions considered in this paper are intended for use in conjuction with the algorithms fed into the information and computing equipment of the Nuclear Power Station in order to monitor the power distribution. However, after making certain slight 105 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 changes, these methods may also be used for other problems of discrete measurements (for example, in determining the temperature fields in the reactor, radiation fields and spectra in the biological shielding, and so on). In conclusion, the authors wish to thank I. S. Akimov for the results of the physical calculations relating to the Beloyarsk Nuclear Power Station and also M. P. Bodrilin, Yu. I. Volod'ko, and V. 0. Steklov for help in the measurements. LITERATURE CITED 1. I. Ya. Emellyanov et al., At. Energ., 30, 275 (1971). 2. B. G. Dubovskii et al., International Conference on Physical Problems in the Design of Thermal Reactors, London, June (1967). 3. I. Ya. Emel'yanov et al., At Energ., 30, 422 (1971). 4. I. Ya. EmePyanov, L. V. Konstantinov, and V. V. Postnikov, Transactions of a Conference of International Atomic-Energy Agency Experts, IAEA-119 (1969). 5. E. S. Wentzel, Theory of Probabilities [Russian translation], Nauka, Moscow (1964). 6. Yu. L. Rozov et at., Avtometriya, No. 5, 7 (1968). 7. W. Legget, Trans. ANS, 9, 484 (1966). 106 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 DEPOSITS ON VK-50 FUEL ELEMENTS A. I. Zabelin, B. V. Pshenichnikov, and T. S. Svyatysheva UDC 621.039.524.4-97: 621.03.955.336 The VK-50 water-cooled water-moderated pressure-vessel boiling-water reactor incorporates a cylindrical pressure vessel with a removable cover. The pressure vessel and the cover are hardfaced with 1Kh18N9T austenitic steel. The in-core operating pressure is 70-100 kg/cm2. The core fuel volume, also known as the small core, consists of 91 fuel assemblies. The natural coolant circulation speed while the fuel assembly is present in the core was 0.5 m/sec. The mean ir- radiation level of the core was 36 kW/liter. The character of the deposits depends on the heat-transfer and hydrodynamical operating conditions of the fuel assemblies, and on the composition of impurities in the coolant. The latter are in turn a func- tion of the water-chemical conditions and of the stability of the structural materials against corrosion and erosion. The contact area presented by the structural materials to the coolant is cited below (in percent- age of total areas): Brass (L-68) 52.1 Carbon steel (St. 3, St. 20, St. 22k) 39.1 Stainless steels (1Kh18N9T, 1Kh13, 3Kh13) 5.6 Zirconium alloys 3,2 The corrosion rate and the yield of corrosion products affecting the coolant both depend on the quality of the coolant (see Table 1). Corrosion products, upon leaving the surface of the corroding materials and entering the coolant stream, become activated in the reactor core and migrate through the loop. This article cites some of the results obtained in studies of deposits formed on the surface of a fuel element that had seen 155 effective full days of service in core from the start of the reactor campaign. The exposure time involved was longer than ten months. Sampling and Sample Analysis Procedure Visual inspection of the surface of the fuel element revealed that the fuel element becomes coated with a reddish-brown film composed of corrosion products. At a distance of 1m from the top of the fuel element, we find a white incrustation TABLE 1. Basic Criteria for Water breaking through at sites where the top film cover is -Chemical Conditions impaired. Physicochemical variables Coolant Five samples scraped off the surface of the fuel feed- water reactor loop water reactor loop element were found to be flaky formations which were steam sparingly soluble in acids even after heating. The chem- pH value 8,3 9,5 ical composition of the deposits was determined on the Dissolved oxygen, mg/k 0,05 0,20 30,00 basis of standard physicochemical procedures of analysis. Total amount of corro- These samples were also subjected to y-ray spec- sion products, mg/kg 0,50 1,00 0,05 trometric analysis. The detector employed was aFEU-56 Translated from Atomnaya nerg-iya, Vol. 34, No. 2, pp. 81-84, February, 1973. Original article submitted May.4, 1972. O 1973 Consultants Bureau, a division of Plenum PUblishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article cannot be reproduced for any purpose whatsoever without permission of the publisher. A copy of this article is available from the publisher for $15.00. 107 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Count rate, teL units 4 3 2 0 0,200 0,511 0,835 1120 1,330 0,5 1,0 7-photon energy, MeV 2 92 / 0,835 1,170' 1,120 1,330 1,5 0 0,5 1,0 1,5 7-photon energy, MeV Fig. 1 Fig. 2 Fig. 1. Typical y -ray spectrum of deposits on VK-50 fuel elements. Fig. 2. y-Ray spectrum of deposits on VK-50 fuel elements (zinc- depleted sample). photomultiplier with a Nal (T1) 70 X 70 mm crystal. Pulses from the detector were amplified by a quantity- manufactured UIS-2 broadbanded amplifier and were placed across the input of an AI-256 multichannel pulse height analyzer. The 'y-ray spectra obtained on the multichannel analyzer were recorded by a BZ-15 digital printout and by an EPP-09 automatic electronic potentiometric recorder. The spectrometer resolution was 10% at the Cs137 y-line (0.661 MeV). The FEU-56 photomultiplier was supplied from a type VS-22 quantity-manufactured stabilized voltage power supplies package. Fluctu- ations of the output voltage from ratings were not greater than 0.01% in response to 10% changes in line voltage or power supplies voltage. Four peaks are clearly in evidence in 'y-ray spectrum shown in Fig. 1, in the energy range beyond 0.2 MeV: 0.511, 0.835, 1.120, and 1.330 MeV. Those peaks can be interpreted as photopeaks due to 'y-photons emitted by Mn54 (0.834 MeV), Zn65 (1.120 MeV), and Co60 (1.330 MeV), with the 0.511 MeV peak considered an outlier. This last peak is identified as the photopeak of annihilation radiation of positrons formed in the decay of the nuclide Zn65. Consequently, gamma-ray spectrometry of the specimens made it possible to determine the presence of the radioactive isotopes Mn, Zn65, and Co6.0 in the deposits on the fuel elements. The isotopes Na22, Fe59, CO, and Zr95 + Nb95 were also detectable in the deposits. But photopeaks due to the 'y-photons emitted by Na22 (1.277 MeV), Fe59 (1.289 and 1.098 MeV), and Coe? (1.170 MeV) lie in the region of the photopeak due to 'y-photons emitted by Zn65 (1.120 MeV) and Con (1.330 MeV). The 108 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 TABLE 2. Averaged Content of Elements in Deposits of Corrosion Products on Fuel Element Chemical composition of deposits Sources of origin element content, wt% reactor loop facilities and equipment structural materials Iron 39,0 Turbine condensers, condenser piping, deaerators, feed- water lines, steam piping, turbine Carbon steel (St. 3, St. 20, St. 22k) Manganese 5,0 In-pile surfaces, HPS* steam lines, feedwater header, Stainless steel (1Kh18N9T, Nickel 0,5 louvered control devices in HPS and LPSt systems, evap- and (0Kh18N10T) and Chromium 0,2 oration plant. steam turbine buckets, scramming and control system screws chromium steel (1Kh13 and 3Kh13) Copper 35,0 Piping system of turbine condensers and LPH* Brass (L-68) Zinc 20,0 Cobalt ( 0,1 Thrust bearings of feedwater pumps, hardfacing of third and fourth stages of turbine low-pressure cylinder Stellite (45-50% Co) and T15K6 alloy (6% Co) " High-pressure steam separators. t Low-pressure stearn separators. *Low-pressure heaters. TABLE 3. Relationship of Radioisotopes in Deposits on Fuel Elements (%) Radioisotope Relative activity* Mn54 2,5?0,4 92,0+3,4 7 maximum in the spectrum of Compton electrons due to Zn65 y-photons, and the photopeaks due to the 'y-photons emitted by Co58 (0.805 and 0.814 MeV) and by Zr95 + Nbn (0.756, 0.723, and 0.768 MeV) are found in the region of the Mn54 (0.835 MeV) photopeak. Control experiments Zne5 were staged in order to ascertain whether nuclides, of Coo 5,1?0, which the photopeaks might be masked by strong lines, were also present. A weighed aliquot of the sample scraped off the outer surface of fuel elements was fused with a fivefold excess of potassium hydrogen sulfate (KITS04) in a muffle furnace at temperatures 900-950?C. The re- sulting amalgam or alloy was dissolved in 20% hydrochloric acid upon heating, and was diluted with de- salinated water. The solution resulting was then passed down a chromatographic column, and mixtures of isotopes or individual isotopes were isolated with the aid of radiochemical techniques. Filter paper moistened in appropriately prepared solutions was sealed in a polyethylene packet, and the 'y-ray spectrum of the sample was then taken. The spectrum of a zinc-depleted sample is shown in Fig. 2. It is clear from a comparison of the 'y-ray spectrum so obtained and the primary spectrum (see Fig. 1) that the intensity of the Zn65 photopeak decreased appreciably, while the Co" photopeak (1.330 MeV) gained in intensity. Because of the decline in the annihilation radiation peak, a peak began to show up in the vicinity of 0.6 MeV, as the maximum in the spectrum of Compton electrons due to the 0.835 MeV 'y-photons. It is clear in Fig. 2 that no new y-lines were detected in the spectrum. Sodium is then isolated by chemical means from the zinc-depleted sample obtained in the preceding control experiment. The y-ray spectrum of the sample depleted of zinc and sodium does not differ from that of the sample depleted of zinc alone. In order to check for the presence of Na22 and Fe59 in the sam- ple, we ran repeat tests to determine the content of those isotopes, using independent methods. Cobalt was isolated from the working sample. Manganese was isolated along with the cobalt. The resulting 'y-ray spectrum of the sample now coincided with that of pure Zn65. Filtrates from the same samples were tested as an additional check. No new 'y-emission lines were detected in the spectrum. The relationship between radioisotopes present in the deposits bulit up on the fuel elements was specific for each power station tested, and depends on the structural materials used [1]. "Averaged from five samples Discussion of Results of Measurements Elements traceable to corrosion and erosion in the stream (iron, manganese, chromium, nickel, copper, zinc) or to naturally occurring impurities in the water (calcium, magnesium, silicon) were found in aliquot volumes of solutions of five samples scraped off the surfaces of the fuel elements. 109 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 It is clear from Table 2 that the deposits consist primarily of compounds of iron (39%), copper (35%), and zinc (20%). Manganese is represented much less conspicuously in the deposits, and there is very little nickel or chromium present. Considerable quantities of zirconium and niobium (elements found in corrosion products of the fuel-element cladding) were not detected. Table 3 displays the relationship between the activities of corrosion products incorporating the iso- topes Zn65, Mnm, and Coe?, all calculated for the time of reactor shutdown. As pointed out earlier, the fuel element under investigation was kept for over ten months in the cooling pond. During that time, the activity of all of the other isotopes decreased to such an extent that the photopeaks associated with the 'y-photons they emitted were masked by far more intense y-lines (mainly those due to Zn65). One curious fact is the level of over 90% activity of the samples attributable to y-emission by Zn65, a nuclide formed in the reaction Zn64(n, y)Zn65 (abundance 48.89%). We can infer from those data that brass should be avoided as a structural material in a power station loop, in the case of a single-loop system of the type selected for the VK-50 reactor power station, in order to improve the radiation situation. The isotope Mn54 is formed principally in a (n, p) reaction, from the isotope Fe54 (abundance 5.81%) [2], and to a much lesser extent in a (n, 2n) reaction from the isotope Mn55 (abundance 100%). The activity of Mn54 is therefore proportional to the concentration of iron corrosion products. The isotope Co60 is formed primarily through the reactions Co50(n, y)Co6? (abundance 100%) and Nin(n, p)Co6? (abundance 26.16%). Since no cobalt was detected through chemical analysis of the samples, it may be surmised that the isotope Co60 owes its origin here principally to the second reaction, from the nickel. CONCLUSIONS 1. Nuclear electric power generating stations based around a VK-50 reactor differ from other power stations based around boiling-water reactors in the typically high content of copper and zinc compounds in the deposits, on account of the brass used in the turbine condenser and in the low-pressure heater on stream in the primary loop. 2. The principal component of the deposits on the fuel element, responsible for ?90% of the long- lived isotope, is the isotope Zn65. 3. Despite the very limited dimensions of the stainless steel surfaces, some Con was nevertheless detected in the deposits. LITERATURE CITED 1. V. P. Pogodin (editor), Corrosion of Structural Materials in Water-Cooled Reactors [in Russian], Atomizdat, Moscow (1965). 2. I. P. Selinov, The Nuclides (Reference Tables) [in Russian], Nauka, Moscow (1970). 110 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 SOME PHYSICAL AND MECHANICAL PROPERTIES OF URANIUM ? ZIRCONIUM ALLOYS AT LOW TEMPERATURES G. B. Fedorov, M. T. Zuev, E. A. Smirnov, and A. E. Kiss ii' UDC 537.311.31: 669.822: 539.67 Earlier investigations into the thermodynamic [1] and diffusion [1, 2] properties as well as the spe- cific heat [3] of uranium? zirconium alloys at high temperatures have shown that the extrema appearing on the concentration dependences of these properties lie in a range of compositions which, at lower tempera- tures, correspond to the 61 phase [4]. In this range of compositions (22-35 at. % uranium*) the integrated thermodynamic functions (molar free energy and molar enthalpy) exhibit their maximum negative deviations from ideal behavior [1], while the specific heat exhibits its maximum deviations from the Neuman and Kopp rule [3]; the mutual diffusion coefficients pass through a minimum and the activation energy reaches a maximum [1, 2]. Further analysis of the results of [3] in relation to the specific heat of uranium ? zir- conium alloys showed that, even at room temperature, there was a slight deviation from the additivity law, with a maximum in the region of the Si phase. In this paper we shall present the results of a fresh study of certain physical properties of uranium ?zirconium alloys at room and negative temperatures. We examined the following properties: specific electrical resistance (resistivity), integrated low-temperature thermo-emf, internal friction, Young's modulus, and hardness. 140 120 100 0 ? 80 60 40 20 0 20 40 60 70 80 00 14wt.% ir 160 Fig. 1. of the resistivity of uranium?zir- conium alloys at temperatures of: 1) 295?K; 2) 77.4?K; 3) 4.2?K. 3 , 20 40 60 14 at. vio Concentration dependence Alloys and Method of Investigation. We studied samples of pure zirconium and uranium as well as alloys of these containing (according to measurements of the charge) 14.1; 27.7; 41.6; 60.5; 87.9 and 94 at.% of uranium. The method of preparation and the dimensions of the samples were analogous to those described in [3]. The samples were studied in the annealed state (being first held in a dynamic oil vacuum of 3.10-1 mmHg at 1000?C and then cooled slowly). The electrical resistance was measured at room tempera- ture, Tr = (295 ? 3)?K, in liquid nitrogen at Tn = (77.4 ? 0.7)?K, and in liquid helium at Th = (4.22 ? 0.02)?K by a four-contact potentiometric method, with two directions of the low-density current (0.1 A/cm2). In calculating the resistivity at low tem- peratures, the geometry of the samples was taken to be exactly the same in each case. The low-temperature thermo-emf was determined [9] relative to copper, using a constant temperatue gradient AT = Tr ? Tn = (216 ? 5), and also by using the recording of a preamplified signal. *According to other investigations, the range of compositions corresponding to this phase (denoted in different ways by different authors) extends from ^,26.6 to ?33.4 [5], from 24.5-25 to ?31.5 [6], or from ^.24.5 to 29.5-30 at.% uranium [7, 8]. Translated from Atomnaya Energiya, Vol. 34, No. 2, pp. 85-88, February, 1973. Original article submitted December 30, 1971. 0 1973 Consultants Bureau, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article cannot be reproduced for any purpose whatsoever without permission of the publisher. A copy of this article is available from the publisher for $15.00. 111 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Fig. 2 40 20 '20 40 50 U,at.% Fig. 3 Fig. 2. Dependence of the integrated thermo-emf of uranium ? zir- conium alloys (AT = 216?K) on the uranium concentration. Fig. 3. Dependence of the background of the internal friction on the composition of uranium ? zirconium alloys at temperatures: 1) 273?K; 2) 173?K; 3) 77.4?K. The elastic modulus and internal friction at temperatures between Tn and Tr were determined by a method based on resonance bending vibrations at a frequency of ?1 KHz [10]. The hardness was measured in a Rockwell apparatus with a load of 100 kg. At least ten measurements were made with each sample. Electrical Resistance. The concentration dependence of the resistivity (Fig. 1) at room, nitrogen, and helium temperatures has a maximum in the range of alloys containing 22-35 at.% uranium, i.e., in the range of the, 61 phase; the single-phase (1 phase) alloy of zirconium with 27.7 at.% of uranium has not only the highest resistivity among all the alloys studied but also an anomalous temperature dependence of its electrical resistance (as compared with other metals), in that it rises with falling temperature: p r = 159.5; pn = 162.3; ph = 163.4 tiS2 ? cm. In the two-phase regions (a Zr + 61 and 61 + au) the resistivity of the alloys varies with composition in a manner corresponding to almost hyperbolic curves; the resistance increases with increasing proportion of the ?i phase. The two-phase alloys have a normal (positive) tem- perature coefficient of electrical resistance diminishing with increasing amount of the 61 phase. Measure- ments at 4.2?K showed (Fig. 1) that the equilibrium alloys of the uranium ?zirconium system were not superconducting. The results of our present measurements of the resistivity of uranium ?zirconium alloys at room temperature agree closely with our earlier results obtained with samples annealed at 580?C for 500 h [3] and also with the results of [4] relating to samples annealed at 500?C for 1000 h. A study of the electrical resistance, of zirconium alloys containing 26 and 30 at.% uranium [11] showed that the 6-phase of these alloys had a negative temperature coefficient of electrical resistance in the tem- perature range 90-870?K. There are no data regarding the resistivity of binary uranium ? zirconium alloys at very low (under 90?K) temperatures. Thermo-emf. The curve relating the low-temperature integrated thermo-emf to composition (Fig. 2) is analogous to that representing the electrical resistance: the maximum thermo-emf also corresponds to the region of the 61-phase; alloys containing a large proportion of the 61-phase have a thermo-emf with a sign differing from that of the original components. Since g (k/e)AT1n(n1/n2) (where k is BoltzmannTs con- stant, e is the charge on the electron, AT is the temperature gradient, n1 and n2 are the numbers of con- duction electrons in unit volumes of the metals in contact), the change in the sign of the thermo-emf means, in particular, a change in the concentration of conduction electrons in the alloy under consideration. Internal Friction. There are no sharp peaks on the temperature dependence of the internal friction of uranium, zirconium, or zirconium alloys containing 14.1; 27.7, and 41.6 at.% uranium (these being the 112 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 25 2 x 10 260 230 200 170 140 20 40 60 U 110, at.% 0 20 40 ' Fig. 4 Fig. 5 Fig. 4. Elastic modulus of uranium ? zirconium alloys at tem- peratures: 1) 77.4?K; 2) 295?K. 60 U, at.% Fig. 5. Dependence of the hardness on the composition of ura- nium?zirconium alloys (T = 295?K). only alloys so studied) between Tn and Tr; however, the background of the internal friction depends very considerably on the composition of the alloy at both low and room temperatures. We see from the curves relating the internal-friction background to the uranium content (Fig. 3) for three temperatures (77.4; 173, and 273?K) that the greatest deviation (in the sense of a reduction) from the law of additivity among all the alloys studied always occurs for those containing 27.7 at.% of uranium, i.e., in the region of the 61 phase. Young's Modubis. On measuring the elastic modulus at 293 and 77.4?K we also found a slight devia- tion from the law of additivity in the sense of an increase in the Young's modulus of the alloy corresponding in composition to the 61-phase (Fig. 4). Hardness. The curve relating the hardness of uranium?zirconium alloys to composition (Fig. 5) has no sharply-expressed peaks. A flat hardness maximum occurs for alloys containing 40-90 at.% uranium; in the region of the 61 phase there is a slight deviation of the hardness values from the smooth curve (in the sense of a reduction), in agreement with the data of [4]. On the basis of the foregoing results we may draw certain conclusions regarding the nature of the chemical bond in the 61 phase of uranium ?zirconium alloys. This phase cannot be regarded as belonging to the class of ordering solid solutions. The increase in the electrical resistance and the slight reduction in the hardness of annealed 61 alloys testify to the accuracy of this assertion. The high resistivity, the change in the sign of the thermo-emf,and the anomalous (for metals) tem- perature coefficient of electrical resistance (the slight semiconducting behavior of the conductivity at low temperatures) indicate that some of the electrons in the 61 phase are bound. A reduction in the number of free electrons is possible when stronger directional bonds are created. The thermodynamic and diffusion characteristics of uranium?zirconium alloys [1-3] in fact indicate an increase in the strength of the inter- atomic bond in the 61 phase as compared with solid solutions based on uranium and zirconium. This is also indicated by the reduction in the background of internal friction (Fig. 3) and a slight increase in elastic modulus (Fig. 4) in the 61 phase relative to the additive law. Since the appearance of an ionic component is of low probability, owing to the very slight difference between the electronegativities of uranium and zirconium, we may reasonably assume that the interaction between the components in the 61 phase is characterized by a mixed metallic ?covalent rather than a purely metallic type of chemical bond. When covalent bonds are formed, the concentration of the conduction electrons diminishes and may even pass into the range of "semiconducting" concentrations, which leads to a considerable increase in the resistivity and a change in the sign of the thermo-emf as compared with the original components. It was indicated earlier [12] that compounds with a mixed type of chemical bond were often semiconductors. 113 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Our conclusion as to the existence of a metallic ?covalent type of chemical bond in the 61 phase of uranium ?zirconium alloys in no way contradicts the physical nature of the uranium, for which covalent bonds are quite typical [13], nor the assumption as to the partly ordered, layer-like structure of the 61 phase [14-16], since covalent bounds may arise for a partly ordered disposition of the atoms in the crystal lattice. This conclusion is also in accord with the results obtained at high temperatures (outside the range of existence of the 61 phase) [1-3], since the extrema there observed on the concentration dependences of the physical properties may be explained by the fact that the rupture of the covalent bonds and the dis- ruption of the partial order take place gradually over a wide range of temperatures. LITERATURE CITED 1. G. B. Fedorov and E. A. Smirnov, At. Energ., 21, No. 3, 189 (1966). 2. G. B. Fedorov, E. A. Smirnov, and F. I. Zhomov, in Metallurgy and Metallography of Pure Metals, No. 7 [in Russian], Atomizdat, Moscow (1968), p. 116. 3. G. B. Fedorov and E. A. Smirnov, At. Energ., 25, No. 1, 54 (1968). 4. 0. S. Ivanov and G. N. Bagrov, in: Structure of Alloys Belonging to Certain Systems Including Uranium and Thoriuni[in Russian], Gosatomizdat, Moscow (1961), p. 5. 5. J. Duffey and C. A. Bruch, Trans. AIME, 212, 17 (1958). 6. H. Sailer and F. Rough, Nucl. Engng., Pt. 1, 56 (1954); Metallurgy of Zirconium [Russian trans- lation], IL, Moscow (1959), p. 269. 7. H. Sailer, Second Nucl. Eng. and Sci. Conf. Paper 57-NESC-20 (1957); At. Energ., 3, No. 8, 176 (1957). 8. V. I. Kutaitsev, Alloys of Thorium, Uranium, and Plutonium [in Russian], Gosatomizdat, Moscow (1962), p. 130. 9. M, T. Zuev, Yu. F. Bychkov, and A. N. Rozanov, in: Metallurgy and Metallography of Pure Metals, No. VI [in Russian], Atomizdat, Moscow (1967), p. 75. 10. G. F. Feforov, ibid., p. 68. 11. R. D. Barnard, Pro. Phys. Soc., 78, No. 503, 722 (1961). 12. B. G. Livshits, Physical Properties of Metals and Alloys [in Russian], Mashgiz, Moscow (1959), p. 215. 13. A. N. Holden, Physical Metallurgy of Uranium [Russian translation], Metallurgizdat, Moscow (1962), p. 38. 14. E. Boyko, Acta Cryst., 10, 712 (1957). 15., J. Silcock, Trans. AIME, 209, 521 (1957). 16. Yu. N. Sokurskii, A. Ya. Sterlin, and V. A. Fedorchenko, Uranium and Its Alloys [in Russian], Atomizdat, Moscow (1971), p. 215. 114 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 PHASE STRUCTURE OF NIOBIUM-BASED ALLOYS IN THE SYSTEM NIOBIUM - TUNGSTEN - ZIRCONIUM - CARBON . M. Savitskii and K. N. Ivanova UDC 669.293.5 The phase diagram of the system niobium-tungsten-zirconium-carbon has been insufficiently investigated, although the corresponding ternary systems niobium-tungsten-zirconium [1], niobium -tungsten-carbon [2] and niobium-zirconium-carbon [2-5] have been fairly thoroughly researched. However, data on the phase structure of multicomponent niobium alloys containing zirconium (titanium or hafnium), carbon, and up to 30 wt.% tungsten are fragmentary [6, 7] and often based on assump- tions. The system niobium-tungsten-zirconium-carbon is one of the most promising for obtaining high- strength niobium-based alloys with precipitation hardening, which are capable of withstanding considerable stresses at high temperatures. In alloys of this system, solid-solution and carbide hardening can be successfully combined. We have investigated the phase structure of alloys of the system niobium-tungsten-zirconium -carbon, rich in niobium and containing up to 4 at.% zirconium and 2 at.% carbon (alloys of the cross section with a constant tungsten content of 10 at.% (18 wt. %) were investigated). The solubility of carbon in niobium-based alloys was determined at 1800?C, which is one of the most probable temperatures of strengthening heat treatment of such alloys with precipitation hardening. TABLE 1. Composition of Niobium-Based Alloys of the System Niobium-Tungsten - Zirconium-Carbon Admixture zirconium carbon zirconium carbon at.% wt.% at.% wt.% at.% wt.% at.% wt.% 0,5 0,46 -- -- 1,5 1,34 0,4 0,047 1 0,92 -- -- 2,5 2,24 0,4 0,047 1,5 1,35 -- -- 0,5 0,45 0,65 0,077 2,5 2,24 -- -- 1,0 0,89 0,65 0,077 4,0 3,57 -- -- 1,5 1,34 0,65 0,076 __ __ 0,2 0,023 2,5 2,4 0,65 0,076 -- -- 0,4 0,047 4,0 3,59 0,65 0,076 __ __ 0,65 0,077 0,5 0,45 1,0 0,118 -- -- 1,0 0,118 1,0 0,90 1,0 0,119 -- -- 1,5 0,179 1,5 1,35 1,0 0,119 -- -- 2,0 0,23 2,5 2,25 1,0 0,119 0,5 0,44 0,2 0,023 4,0 3,60 1,0 0,119 1,0 0,89 0,2 0,023 1,0 0,9 1,5 0,179 1,5 1,34 0,2 0,023 2,5 2,26 1,5 0,178 2,5 2,22 0,2 0,023 4,0 3,62 1,5 0,178 4,0 3,58 0,2 0,023 1,0 0,90 2,0 0,23 0,5 0,44 0,4 0,047 2,5 2,27 2,0 0,23 1,0 0,89 0,4 0,047 4,0 3,63 2,0 0,23 Note The tungsten content was constant in all the alloys, namely 10 at.% (18 wt.%). EXPERIMENTAL METHOD To study the phase regions of the investigated sector of the phase diagram of the system niobium-tungsten -zirconium-carbon we used the microscopic method, together with color etching, and x-ray analysis (phase analysis and determination of the lattice constant); the hardness and microhardness were also measured. Weighed amounts (60g) of the alloys were melted in an arc furnace with a nonconsumable tungsten electrode in an inert atmosphere (purified helium) at 400 torr. To obtain a uniform composition, the bars were inverted five times. The initial materials were niobium, obtained by electron-beam melting (0.005% oxygen, 0.013% nitrogen, 0.015% carbon, and 0.009% hydrogen), zirconium iodide, cermet tungsten, and spectrally pure carbon. Table 1 gives the compositions of the alloys. Most of the alloys were subjected to chemical analysis; this revealed close agreement between the alloy composition and the calcu- lated values. Alloys not doped with carbon contained a small amount of carbon (0.015-0.02 wt. %), which origi- nated from the initial niobium. Translated from Atomnaya tnergiya, Vol. 34, No. 2, pp. 89-92, February, 1973. Original article submitted February 16, 1972. 0 1973 Consultants Bureau, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article cannot be reproduced for any purpose whatsoever without permission of the publisher. A copy of this article is available from the publisher for $15.00. 115 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 412 416 C, wt% 423 0,18 4 In C,a 2,0 AMII/M/MMMIWAr A I FM mirmArer IMF AIMIAN AzarivirAvAwAvir Nb + 10 at. % W4 0 5 2,0 450 45 i0 Zr, at.% Fig. 1. Isothermal cross section at 1800?C of the niobium vertex of the system niobium?tungsten?zirconium?carbon. Fig. 2. Microstructure of alloys quenched at 1800?C (X 500): a) Nb ?0.2 at.% C ?10 at.% W(a-solid soln. );b) Nb? 0.6 at.% C ?10 at.% W (a-solid soln. + Nb2C); c) Nb ? 1.5 at. %C ? 10 at. %W(a-solid soln. + Nb2C); d) Nb ? 0.5 at. % Zr ? 1 at. % C ? 10 at. %W(a-solid soln. + Nb2C); e) Nb ?4 at.% Zr ?10 at.% W(a-solid soln+ W2Zr). The cast alloys were forged at 1350?C and then homogenized in a TVV-5 vacuum furnace at a residual pressure of 5 ? 10-6 torr inthe following stages; at 1900?C for 4 h and at 1800?C for 6 h. Quenching was performed in a current of gaseous helium in a vacuum furnace after high-temperature annealing at 1800?C for 1 h in a vacuum of 5.10-6 torr. The cooling rate in the temperature range of pos- sible decomposition of the solid solution was >40 degree/sec. 116 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 ff,1 3,300 3298 3,295 4284 Nb + 10 at. % W 04 08 1,2 C, at.?70 a 0 04 08 1,2 0 WI 08 1,2 C, at.% C, at. % 410 BO 370 a 350 4) ,g 330 31, 0 290 270 Nb + 10 at. % W 0- "4 , 08 V C, at.% Fig. 3. Lattice constant in alloys of cross sec- tions containing 0.5, 1, and 2.5 at.% zirconium (a, b, c, respectively) as a function of carbon c content. 04 08 12 c,atA 04 08 1,2 16 04 0,8 1,2 C, at.% C,atNo 46' Fig. 4. Microhardness in cross sections of alloys con- taining 0.5, 1.5, 2.5, and 4 at.% zirconium (a, b, c, and d, respectively) and 10 at.% tungsten as a function of car- bon content. To reveal the microstructure we used an etcher consisting of 2 parts of HF, 2 parts of HNO3, 1 part of CH3COOH, and 1.5 parts of H20. The lattice constants were determined by a precision method in Ni Ka-radiation from the (321) line in a black-reflectioncamera (oscillating flat specimen and rotating film). The exposure was 2 h, the stan- dard was gold. X-ray phase analysis was performed on powders in a Debye cameraof diameter 57.4 mm in Cu Ka-radiation (Ni filters, exposure 5 h). Color etching of thin sections was performed in a special apparatus for electropolishing and electroetching at 20V, using the etcher indicated in [8]. The etching time was more then 1 min. The hardness was measured in a Vickers apparatus at load of 30 kg; the microhardness was measured in a PMT-3 durometer at a load of 50 g. RESULTS Using the microscopic and x-ray analysis data and the measured values of the hardness and micro- hardness, we constructed the isothermal cross section of the system niobium -tungsten- zirconium -car- bon at 1800?C up to 4 at.% zirconium and 2 at.% carbon and with a constant tungsten content of 10 at.% in the alloys (Fig. 1). At 1800?C, in these alloys the carbides Nb2C and (Zr, Nb, W)C and the compound W2Zr are in equi- librium with the a-solid solution. At this temperature the solubility of carbon in niobium is "00.55 at.% [9]. According to our data, the solubility of carbon in niobium containing 10 at.% tungsten at 1800?C is also -0.5 at.% (see Fig. 1). Therefore addition of up to 10 at.-% tungsten to niobium has no effect on the solubility of carbon; this agrees with the conclusions drawn by Taylor andDoyle [10]. The microstructure of niobium-tungsten alloys containing up to 0.4 at.% carbon is one-phase (Fig. 2a), but is already two- phase at a carbon content of 0.65 at.% (see Fig. 2b). The phase which separates as thin elongated plates is niobium carbide Nb2C. With an increase in the carbon content of the alloy to 1-2 at.%, Nb2C is obtained in coarser form (see Fig. 2c). The shape and number of the carbide particles are particularly distinct when the material is subjected to color etching; the yellow carbides against the reddish brown background of the solid solution are located at the grains and along the boundaries as acicular plates of the Widmanstatten structure type. 117 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 When about 1 at.% or more zirconium is added to niobium?tungsten?carbon alloys, the solubility of carbon decreases (at 1800?C it falls from ?0.5 to ?0.2 at.% (see Fig. 1)). Determinations of the lattice constant (Fig. 3) and microhardness of the alloys (Fig. 4) confirmed the results of microscopic analysis. The curves plotting the change in the lattice constant and micro- hardness of these alloys exhibit sharp breaks corresponding to the solubility limit of carbon. For alloys containing 1 at.% or more zirconium, the breaks on these curves correspond to 0.2 at.% carbon (see Fig. 3b-c and Fig. 4 b-d). Note that addition of zirconium to the alloys leads to marked crushing of the large carbide inclusions and to their more uniform distribution in the base of the matrix. The phases which segregate out are niobium carbide Nb2C with a hexagonal lattice (see Fig. 2d), and zirconium monocarbide, doped with niobium and tungsten, with an fcc latice: (Zr, Nb, W)C. The slight decrease in the lattice constant with progressive carburization of alloys containing 1-2.5 at.% zirconium (see Fig. 3b-c) indicates that the niobium-based solid solution loses carbon as a result of removal as the compound (Zr, Nb, W)C.. In contrast with the coarse acicular phase, the carbide phase (Zr, Nb, W)C has different and more dispersed segregations. X-ray phase analysis revealed that the alloys in this part of the system contain the compound W2Zr, which is a Laves phase with an fcc MgCu2-type lattice [1, 11]. According to [1], this phase appears in niobium alloys at a 4:1 (wt.%) ratio of tungsten to zirconium. The compound W2Zr is clearly observed in alloys of the system niobium?tungsten?zirconium?carbon. The x-ray diffraction patterns exhibit lines of only two phases: an indium-based os-solid solution with a bcc lattice and a W2Zr phase with an fcc lat- tice. Under the microscope this phase appears as elongated and thickened dark veinlets (see Fig. 2e). The W2Zr phase is not observed in these alloys with a lower zirconium content (1.5 at. %). However, when the alloys simultaneously contain 2.5-4 at.% zirconium and 0.2-2 at.% carbon, the content of this phase is much less owing to combination of zirconium to form the carbide phase (Zr, Nb, W)C. Note that the rate of segregation of the carbide phases is very great; this makes it difficult to obtain strictly one-phase alloys during quenching [12], despite the high cooling rates. The solubility of carbon in the alloys of this part of the system niobium?tungsten?zirconium?car- bon at 1600?C is no different to that at 1800?C, judging from microstructural and x-ray analyses and determinations of the microhardness. Of these alloys, those of niobium and tungsten with up to 0.7 at.% carbon and 1% zirconium have the lowest hardness (up to 180-200 kg/mm2) and maximal technological effectiveness. Alloys containing 0.7-1.5 at.% carbon and 1-2.5 at.% zirconium have a satisfactory plasticity and a hardness of 220-240 kg/mm2. Incorporation of these components within the above limits reduces the plasticity of the alloys owing to an increase in the number and size of the carbide particles. The (Zr, Nb, W)C phase may be an effective strengthener in niobium-based alloys of the system niobium ?tungsten?zirconium?carbon, particularly if the material is subjected to appropriate heat treatment (accelerated cooling after annealing at 1800-2000?C). LITERATURE CITED 1. E. M. Savitskii and A. M. Zakharov, Zh. Neorganich. Khim., 7, No. 11 (1962). 2. A. C. Barber and P. H. Morton, High Temperature Refractory, Metals, New-York?London ?Paris (1966), p. 391. 3. V. S. Emel'yanov et at., in: Metallurgy and Metallography of Pure Metals [in Russian], No. 6, Atomizdat, Moscow (1967). p. 92, 4. P. Stecher et al., Monatsh. Chem., 95, 1630 (1964). 5. E. Delgrosso et al., J. Less-Common Metals, 12, No. 3 (1967). 6. W. Chang, Columbium-Base Alloys, USA Patent No. 3384479, May 21 (1968). 7. A. Dalton and G. McAdam, Metallography and Heat Treatment (Express Information), No. 27, 34 (1970). 8. M. Picklesimer, US Atomic Energy Commission Oak Ridge Nat. Laboratory, Rept. (1957), p. 2297 9. E. Rudy et al., Planseeberichte fur Pulvermetallurgie, 16, No. 1 (1968). 118 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 10. A. Taylor and N. Doyle, J. Less-Common Metals, No. 5, 511 (1967). 11. R. Domogala et al., J. Metals, 5, 73 (1953). 12. F. Ostermann and F. Vollenrat, in: New Refractory Metallic Materials [Russian translation], Mir, Moscow (1971), p. 139. 119 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 EXPERIMENTAL FITTING OF DATA RELATING TO THE IRRADIATION OF GRAPHITE IN REACTORS TO A UNIVERSAL SCALE OF DAMAGE-INDUCING FAST NEUTRON FLUX V. I. Klimenkov and V. G. Dvoretskii UDC 539.16.04:621.039.512.45 This problem arises in connection with matching the neutron-induced damage in graphite irradiated by neutron fluxes of different parameters [1] (for example, when the irradiation takes place in different reactors or in different parts of the same reactor). The point is that the damage suffered by the graphite as a result of irradiation depends on the intensity and energy spectrum of the neutron flux causing the damage. The results of neutron irradiation may be meaningfully compared if the dose is measured in units of the integrated fast-neutron flux causing the damage [2]. If we know the intensity and spectrum oftheneutronl flux, the results may be fitted to this scale by a computational procedure, allowing for the concept of equivalent temperatures [3] and the damaging capacity of neutrons of different energies over the whole spectrum [4, 5]. If the spectrum of the neutron flux is unknown a calibrating experiment differing fundamentaly from experimental matching [6, 7], may be necessary. In the latter case, the neutron flux density is expressed in 2, L7 3 terms of a known spectrum with a specific lower energy limit (for example, >0.18 MeV). 100 150 170 180 t cm-2 4 1,0 ?0 6 _ , 44 _ 42 _ 0,1 , gos 0,04 ? - 402 401 0031(1-0,00514 1( Oaf t ? f0-73 )473- ' -7 4 2 1017 190 Fig. 1. Nomogram for solving the calibration equation in the case of PGG graphite (perpendicular to the direction of cutting the sample). Experimental Method. The calibrating experiment is carried out as follows: An ampoule containing a graphite sample and an activation threshold detector (for example, Ni58) is irradiated in a reactor for a time tirr. The irradi- ation is carried out at that point of the reactor for which matching is required. The ampoule should not seriously affect the parameters of the neutron field. From the specific activity of the threshold detector the equivalent fission neutron flux ONi is determined. For this purpose we use the cross section of the (n, p) threshold reaction averaged over the fission spectrum. The integrated (13f ; .tirr should not deviate very greatly from the range N. 101'-3.101? neutrons/cm2, while the graphite irradiation temperature Tirr should lie in the range 100-150?C. In the irradiated graphite sample the residual radiation increment in electrical resistance Ap/p is determined; then from the fall in electrical resistance which occurs on anneal- ing Ap = f(Tann) the graphite irradiation temperature is found [8]. The temperature measurement may be duplicated by using the diamond method [9]. Translated from Atommaya Energiya, Vol. 34, No. 2, pp. 93-96, February, 1973. Original article submitted January 31, 1972. 120 C /975' Consultants Bureau, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article cannot be reproduced for any purpose whatsoever without permission of the publisher. A copy of this article is available from the publisher for $15.00. Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 neutron/cm2 ? sec 77 72 71 70 89 68 67 66 65 Kv64 53 62 61 60 1013 1012 100 700 7. Fig. 2. Cartesian abacus for the irradiation temperature, neutron flux, and graphite irradiation equivalence criterion. TABLE 1. Results of the Experiments and Analysis Parameter Irradiation channel 14 channel4 I II III IV ti? >(10-12 neutrons /crn.sec2 Oisa,10-18neutrons/crn2 Tirr, ?C Ao mdf' X10-12 neutrons /crn7. sec T, ?C kix 2,55 9,9 4,75 0,155 1,3 0,95 1,3 146 3,32 9,40 6,17 1,68 00 100 150 100 0,64 1,24 0,60 2,40 3,84 2,72 3,68 382 72 78 120 40 2,95 2,50 2,83 2,62 From the value of Ao/p and also that of (13fm deter- mined from the activation threshold detector, with due allowance for the irradiation temperature, we find the conversion factor for converting the equivalent fission neutron fluxes at the points of irradiation in the reactor in question to the universal scale of the fast neutron flux (I.df causing the damage: kix=t:Dafil:Divi ? (1) This is done by means of a calibrating formula [2] derived for graphite of the PGG type cut perpendicularly to the axis of formation Apip = 0.030 (1? 0.00514T) (41)dit ? 10-1?)??75, (2) where T is the irradiation temperature in ?C. The relationship described by this formula is valid for the calibrating value of the damage-inducing flux 0 ') .(-4- 0 '. present in- data of vestigationlothers 771089 34,2 127,9?4 ? 58,2+7 129,7 78Pt192 34,9 135,9?3 ?64,7+5 132,6 81T1201 35,7 139,4+2 138?4 [7] 51,6+4 139,3 85At213 27,9 151,5+2 146?4 [6] 45,8?8 149,0 The possibility of measuring the energy distribu- tions of fragments by means of glass detectors was dis- cussed in [3, 4] for the case of the spontaneously fissile nuclei Cm2" and cf252. The results indicate a certain nonlinearity in the dependence of the diameters of the craters in the glass on the energy of the fragments, which casts doubts upon the possibility of obtaining reasonably accurge mean kinetic energies of the fragments EK by direct calculations based on the track method. * Results of 111 The track method is more promising for measuring EK in the case of nuclei undergoing fission in a mainly symmetrical manner, for which the energy range of the fragments is considerably narrower and the nonlinearity of the relationship between the diameters of the tracks and the energy of the fragments should have a less noticeable effect. The present investigation is aimed at verifying the use of this method of the fission of Re183, Os183, Aul" , Boos by a particles with an energy of 38 MeV. In the experiments we used layers of the isotopes in ques- tion 100-200 pg/cm2 thick; photoemulsion glasses acted as fission-fragment detectors. The irradiated glasses were etched simultaneously in hydrofluoric acid (concentration -48%) for 170 sec. In order to calibrate the energy scale we measured the fragment spectra for the fission of Au and Bi by 38 MeV a par- ticles and that of Th232 by 27 MeV a particles with semiconducting counters. (In the latter case the position of the peaks corresponding to the light and heavy fragments was already well known.) The fragment spectra were measured with glasses and semiconducting counters using exactly the same geometry - at an angle of 900 relative to the axis of the incident particle beam. We made two-series of measurements with different batches of glasses and different etching conditions. The irradiated glasses were inspected under an MIRE-2 microscope, with automatic recording of the results of the measurements on punched tape. Control mea- surements were carried out under a KSM microscope, the reading accuracy of which was about 0.1 ?. The final analysis of the results of our measurements of the fragment spectra was carried out in a BESM-4m computer. For each element we measured up 3000-6000 tracks. Corrections of the kind usual in experi- ments of this type were introduced into the measured values of EK [5, 6]. The results of an analysis of two independent series of measurements coincided, within the range of errors indicated in Table 1. Table 1 gives the measured values of EK, the dispersion of EK, and also the results of calculations of EK based on [1]. Figures 1 and 2 show the energy distributions of the fragments of the compound nuclei studied and the EK distributions of the isotopes T1231 and At213 obtained by means of semiconducting counters and glasses. The measured energy distributions of the fragments of the elements under consideration presented in Table 1 and Figs. 1 and 2 indicate a real possibility of making direct measurements of EK by the "track method" and achieving a fair accuracy in so doing. The results of our measurements, coinciding with the calculated values of EK [1] within the limits of experimental error, lead to the conclusion that the angular momentum introduced into the nucleus by the particles and the excitation energy of the compound nuclei have relatively little effect on the mean kinetic energy EK. Our own measurements of EK agree with the theoretical calculations of [8] and with the experimentally measured values of the kinetic energies of the elements under consideration obtained by means of semicon- ducting counters in earlier investigations [6, 7]. LITERATURE CITED 1. V. Viola and T. Sikkeland, Phys. Rev., 130, 2044 (1962). 2. I. Halpern, Ann. Rev. Nuc. Sci., 9, 245 (1959). 3. V. K. Gorshkov, L. N. Livov, and G. A. Khruleva, At. Energ., 28, 73 (1970). 176 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 4. U. Hoppner et al., Nucl. Instrum. and Methods, 74, 285 (1969). 5. V. N. Okolovich, G. I. Smirenkin, and I. I. Bondarenko, At. Energ., 12, 461 (1962). 6. F. Plasil et al., Phys. Rev., 142, 697 (1966). 7. R. Vandenbosch and J. Huizenga, Phys. Rev., 127, 212 (1962). 8. J. Nix and W. Swiatecki, 'Nucl. Phys., 71, 1 (1965). 177 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 THE AVERAGE NUMBER OF NEUTRONS EMITTED IN THE SPONTANEOUS FISSION OF Cm244, cni246 AND Cm248 V. V. Golushko, K. D. Zhuravlev, Yu. S. Zamyatnin, N. I. Kroshkin, and V. N. Nefedov UDC 539.173.7 Until the present experiments on the measurement of -vp - the average number of prompt neutrons emitted per fission - were formulated, the only even-even isotope of curium for which a substantial number of measurements had been made was Cm244; on the basis of the Cm244 measurements, Konshin's survey report recommended a value of -vp = 2.691 ? 0.032. Only one measurement was known for Cm248 [2] and one for Cm238 [3], and these had been made with relatively low accuracy (3-7%). We therefore thought it desirable to measure for all the nuclei listed above, under identical conditions and in the same experi- mental setup, in order to ascertain how Pp varies with mass number in the fission curium isotopes. Similar measurements were conducted in parallel by G. N. Smirenkin et al. [4]. The fission neutrons were recorded by 48 SNM-18 proportional counters placed in a paraffin moderator 500 mm in diameter and 500 mm in length, with a transverse central channel (diameter 90 mm) for instal- ling the fragment detector. In order to reduce the scattered-neutron background, the neutron detector was placed inside a boron carbide shield 50 mm thick. The recording efficiency for neutrons from the sponta- neous fission of Cf282 was 29%. We used a neutron detector similar to that described in [5], with resolution time of 3 ?sec. The fission fragments were recorded by means of gas-type scintillation detector. The fissionable substance was spread on a stainless-steel substrate. The target spot diameter did not exceed 10 mm. The isotope composition of the targets is shown in Table 1. In the measurement of Tip, the fragment pulses opened the gate circuit for a period of 180 ?sec, during which the neutron pulses were recorded. The reference used in measuring v1 for the isotopes under in- vestigation was Cf282, for which the Pp value was taken to be 3.756 ? 0.010 [1j. We made ten series of mea- surements for each of the investigated isotopes. From the Cf282 calibration target we recorded 12 dis/sec, whereas the values for the curium targets ranged from 1.5 to 3 dis/sec. The experimental results obtained were corrected for the background of random coincidences and for the isotope composition of the targets. As in [5], we introduced a correction for the coincidence of pulses produced by neutrons from a single fission. The role of the variation in neutron-detector efficiency as a function of energy was estimated by comparing the -1,p value for Cm244 obtained in the present study with the value recommended in [1]. The values are in good agreement, which shows that the correction for TABLE 1. Isotope Composition of the TABLE 2. Values of Tp for Curium Iso- Targets topes Target Isotope percentages Present study [4] Data obtained in 197 0-197 1 242 244 245 246 Isotope 248 2,680?0,027 2,927Hh0,027 3,173H-0,022 2,700H-0,014 2,950H-0,015 3,157H-0,015 2,691-P0,032 [1] 3,20H-0,22 [2] 3,11-h0,09 [3] Cm244 CmM6 Cm248 0,03 99,24 0,25 5,57 0,42 0,29 0,31 99,46 1,85 Cm244 CM246 Cm248 92,58 Translated from Atomnaya Energiya, Vol. 34, No. 2, pp. 135-136, February, 1973. Original article submitted July 31, 1972. 178 0 /9 75' Consultants Bureau, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article cannot be reproduced for any purpose whatsoever without permission of the publisher. A copy of this article is available from the publisher for $15.00. Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 the variation in efficiency as a function of energy does not exceed the limits of measurement error. The maximum value of the other corrections discussed in [5) was no more than 0.1% under the conditions of our experiment. Table 2 shows, for comparison purposes, the results of the measurements made in the present study and the data of other authors. It can be seen that the results of the present study are in good agree- ment with the data of [4] and indicate that17p for even isotopes of curium increases linearly as the mass number A increases. This result may be regarded as an experimental coinfirmation of the calculations made in [6] for the function-vp(Z, A). In conclusion, the authors wish to thank L. I. Prokhorova and G. N. Smirenkin for their valuable advice in the construction of the neutron detector, and also to thank A. P. Druzhnov for his help with the measurements. LITERATURE CITED 1. V. Konshin and F. Manero, Energy-Dependent Values for U235 pu23 9 , ty233 pu240 PU2" and the Status of 1; for Spontaneous-Fission Isotopes, Vienna, IAEA (1970). 2. Major C. Thompson, Phys. Rev., C2, 763 (1970). 3. C. Orth, Nucl. Sci. and Engng., 43, 54 (1971). 4. L. I. Prokhorova et al., At. Energ., 33, 767 (1972). 5. L. I. Prokhorova et al., At. Energ., 30, 250 (1971). 6. I. I. Bondarenko et al., Second Geneva Conference, 1958 [in Russian], Vol. 1, Atomizdat, Moscow (1959), p. 438. 179 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 COMECON NEWS COLLABORATION DAYBOOK The 15th session of the PKIAE SEV work group on reactor science and engineering and nuclear power was held September 26-29, 1972 at Marianske Lazen (Czechoslovakia). Specialists from Bulgaria, Hungary, East Germany, Poland, Rumania, the USSR, and Czechoslovakia participated in this session, as well as a staff member of the COMECON Secretariat. The positions originally taken in forecasting calculations were approved in the course of discussions on the development of an updated prognosis of nuclear power development in the COMECON member ?nations. The work team discussed proposals on the program of collaboration in the field of research reactors, and concluded that it is now feasible to set up a KNTS body on research reactors. A draft plan for the Commission's work in the field of reactor science and engineering and nuclear power was approved, and various other topics in the organization of collaborative efforts were also discussed. The first session of the KNTS on water management for nuclear power stations was held at Magdeburg (German Democratic Republic) September 26-29, 1972. Participating were specialists from Hungary, East Germany, Poland, Rumania, the USSR, and Czechoslovakia, as well as a staff memberof the COM- ECON Secretariat. On the basis of an analysis of research carried out in the COMECON member nations on water man- agement at nuclear power stations, results of which were discussed at a symposium in May 1972, this KNTS worked out proposals on the basic trends in scientific-research work, and proposals on improving the program of collaboration in this domain. Particular emphasis was placed on the fact that construction of nuclear power stations in areas with differing water supply facilities must be accompanied by improvements and refinements in the technology of water treatment, with due attention given to geographical and seasonal conditions. It is important that sufficient attention be given to those aspects of water management in the initial design stage of nuclear power stations. The fourth session of the KNTS on radiation engineering and technology was held in Budapest, October 5-7, 1972. Members of the council participated alongside experts from Bulgaria, Hungary, East Germany, Poland, Rumania, the USSR, Czechoslovakia, staff members of the COMECON Secretariat, and a represen- tative of the Interatominstrument international economic association on nuclear instrumentation. The agenda specified 12 topics, including a summary of the conference of specialists of COMECON member nations recently held on implementation of high-level radiation facilities and radiation technology in indus- try. The council discussed and approved a report on industrial realization of processes designed for radia- tion fabrication of wood and plastic materials (E. Plander, Czechoslovakia), and accepted this report as a basis for working out measures on the industrial acceptance of processes for radiation modification of wood in the national economies of interested nations. The following points were noted. 1. Wood and plastics can be used in shipbuilding, in the chemical process industry, in the production of textiles, in civil engineering and construction work, and in other areas of modern technology, and can partially replace materials made from more expensive hardwoods (oak, etc.). 2. In some capitalist countries (USA, France, Finland, etc.), industrial production of commodities (predominantly parquet flooring) from radiation-modified wood has been organized. Despite the compara- tively high cost of those commodities, they are in great demand because of their excellent service qualities. Translated from Atomnaya Energiya, Vol. 34, No. 2, pp. 137-138, February, 1973. C 1973 Consultants Bureau, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article cannot be reproduced for any purpose whatsoever without permission of the publisher. A copy of this article is available from the publisher for $15.00. 180 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 , 3. In COMECON countries, radiation modification of wood is in the pilot plant and testing stage. In the,Soviet Union, for example, the basic parameters of a technological process for production of some commodities from radiation-modified wood have been worked out, full-scale tests of flooring made of modified parquet have been staged, and the prerequisites for instituting a new method in industrial pro- duction have been created; experiments designed to study a technology for impregnation by monomers and radiation modification of furniture plywood, parquet flooring, and curing of paint and varnish coatings for wood materials were carried out. A report presented by a KNTS member, B. Gratu of Rumania, on training of specialists in radiation engineering and technology was approved, and such forms of training and skills upgrading of specialists as mutual exchange of instructors and guest lecturers., organization of special courses, and seminar schools, etc., which are the forms most popular and most widely practiced, were approved and recommend- ed. In particular, the KNTS voted a resolution on the feasibility of organizing, to begin with, a series of lectures on technological dosimetry of radiation processes, and took into consideration a declaration by the Rumanian delegation to the effect that, at any time later than 1973, such courses can be organized in Rumania. The topical structure of the symposium on radiation processing of foodstuffs and agricultural products (Bulgaria, October 1973) was worked out, and arrangements for further preparatory work on the symposium were approved. The Council approved plans for the development of unitized assemblies in radiation facilities, for scientific forecasting of the development of basic trends in radiation technology, unified public-health rules and regulations on radiation devices and operation of radiation facilities, unified procedures of dosimetric monitoring of radiation technological processes. The 1973 work plan was discussed and the agenda of the fifth session of the Council (scheduled for East Germany, April 1973) was discussed. The session took place in a businesslike and comradely atmosphere. The participants took favorable note of the excellent organization of the session, and the work done by the Hungarian delegation in expediting the session. The third KNTS session on radioactive wastes and deactivation was held October 8-11, 1972, at Kolobrzeg (Poland). Specialists from Bulgaria, Hungary, East Germany, Poland, Rumania, the USSR, and Czechoslovakia, as well as COMECON Secretariat staff members, participated in the work of the conference. Assessments of the results of work done with existing facilities designed for reprocessing of low- level and medium-level radioactive wastes, and a "Procedure for geological, hydrogeological, and physico- chemical research in prospecting, exploration, and validation of the suitability of geological structures for safe burial of radioactive wastes," were discussed, as well as criteria for selecting appropriate techniques for the immobilization of nuclear power station radioactive process wastes in relation to the properties of the wastes and the natural disposal conditions. The 24th session of the work group on nuclear instrumentation met October 10-13, 1972 in Sofiya. Delegations of specialists from Bulgaria, Hungary, East Germany, Poland, Rumania, the USSR, and Czechoslovakia, took part in the session, and representatives of the international association Interatomin- strument were also in attendance. Scientific and technical collaboration between COMECON member nations in the field of nuclear instrumentation were discussed. The specialists discussed the design of a thesaurus suggested by the German Democratic Republic delegation for organization of centralized coverage and searches of the worldwide patent literature on the class of nuclear instruments, and decided to request that PKIAE SEV recommend this design for use in COMECON member nations over a three-year period with subsequent refinements and supplements. The work group heard a report by Soviet specialists on the general concept of setting up systems of modules and instruments based on integrated circuitry, and suggested that a detailed concept be worked out with subsequent preparations of recommendation on standardization. A broad exchange of information on the status of developments and production of nuclear physics equipment based on integrated circuitry in the COMECON member nations was arranged. A project submitted by the Polish delegation incorporating plants for preparing and holding a symposium on the topic "Development of integrated-circuit nuclear equipment," was discussed and approved (scheduled for April 1973, in Poland). 181 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 The specialists discussed topics related to the work plan on the topic "Development of instruments and equipment for scramming and control systems, dosimetric monitoring and radiometric monitoring of VVER reactors," and accepted an informational report by the Polish delegation on the status of preparations for the conference on "Monitoring and control of nuclear reactors and nuclear power stations" (to be held in October 1973, in Poland). A report prepared by the Hungarian delegation on the progress of work on the topic "Development of procedures and instruments for nuclear medicine," was discussed and approved. A program for the forthcoming April 1973 coordination conference on nuclear medicine was prepared and approved. The work group discussed 13 draft recommendations on standardization on basic parameters, techni- cal specifications, and techniques for testing various nuclear instrumentation products, and adopted ap- propriate resolutions. Proposals for the 1973 work plan and a draft resolution for PlgAE SEV on nuclear instrumentation were agreed upon. A seminar on exchange of experience accumulated to date on the building and acceptance of power plants incorporating fast reactors, specifically"the BOR-60 reactor, was held October 25-28, 1972 at Dimitrovgrad (USSR), following the PK1AE SEV guidelines. The seminar attracted about 70 specialists from East Germany, Poland, Rumania, the USSR, and Czechoslovakia. Nineteen reports were heard and discussed, with Soviet specialists presenting results of scientific-research based on the BOR-60 reactor power plant. The participants of the seminar visited the BOR-60 power plant and were familiarized with its per- formance and history. The seminar contributed to the further development of collaboration between COMECON member na- tions in the field of scientific-research and design and development work concerned with high-output fast power reactors. 182 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 NEWS THE ALL-UNION CONFERENCE ON THE USE OF RADIATION TECHNIQUES IN AGRICULTURE D. A. Kaushanskii The All-Union Conference on the Use of Radiation Techniques in Agriculture was held at Kishinev, October 2-5, 1972. Scientists and agricultural workers participated in the work of the Conference. About 25 reports were presented in plenary meeting. The Conference dealt with: general problems of agricul- tural radiobiology; irradiation of seeds before planting; radiation genetics and selection; isotopes and radiation in plant protection; isotopes and radiation in plant physiology; and the use of radiation in the storage and technological processing of agricultural products. The Conference was opened by G. Ya. Rud', Corresponding Member of the Academy of Sciences of the Moldavian SSR, who observed that the Conference was being held at a time when the use of radiation techniques in the fields of Moldavia was becoming a significant reality, and the results of many years of research by radiobiologists were being corroborated in practice. In his welcoming speech, I. N. Berezhnoi, Agriculture Minister of the Moldavian SSR, discussed the results of the use of Kolos industrial mobile gamma units in the Republic over a five-year period, as well as some results of the irradiation of seeds before planting, including corn, sunflowers, and sugar beets, which are crops of great importance to the Republic. The Ministry of Agriculture of the Moldavian SSR is studying the problems involved in further incorporating into agricultural practice the method of pre- planting irradiation of seeds by means of Kolos units. It was noteworthy that the preplanting irradiation of corn, a crop which occupies approximately 380,000 ha of the Republic, with an average yield of 3,800 kg /ha (weighted average for 1968-1971), made possible an additional output of about 150,000 tons. This is done by using 15 to 20 Kolos units, costing approximately 1 million rubles. The economic benefit of this measure is about nine times as high as the cost price of the Kolos units. A. M. Kuzin, N. F. Batygin, K. I. Sukach, N. M. Berezina, and D. A. Kaushanskii spoke in plenary meeting; they discussed the trends and levels of present-day theoretical investigation and also gave an es- timate of the results achieved by production testing of the method of preplanting irradiation and of the radia- tion technology developed for this purpose. Reports on the use of atomic energy in various branches of agricultural science and in production were presented by V. N. Lysikov (radiation mutagenesis in agri- cultural plants), S. V. Andreev (the struggle against agricultural plant pests), and others. A. M. Kuzin gave a general discussion of the theoretical prerequisites and experimental studies on the effects of ionizing radiation and pointed out the role of free radicals and changes in the permeability of biological membranes in the acceleration of metabolism, and the role of other factors in the develop- ment of the theoretical foundations of preplanting irradiation. In addition, he spoke of a possible sequence of processes taking place in the preplanting irradiation of seeds which will ensure their more rapid germi- nation development, and tillering, earlier blooming, and increased yields. Advances in radiobiology and their practical utilization in agriculture were discussed by N. F. Batygin (Agrophysical Institute, Leningrad). He noted that radiation can be used successfully as part of a general system of agricultural measures designed to increase yields, and he pointed out the need for broader in- vestigations into the theoretical foundations of mutagenesis and radioselection, as well as the use of radiation protectors and radiation sensitizers in plant protection. The results of extensive production tests and the incorporation of preplanting irradiation and Kolos gamma units into Moldavian agriculture were discussed by K. I. Sukach (Kishinev Agricultural Institute). Kolos mobile gamma units, industrially produced and having a capacity of about 1 ton/h, made it possible in 1968-1972 to conduct tests of this new agricultural Translated from Atomnaya Energiya, Vol. 34, No. 2, pp. 139-140, February, 1973. 0 1973 Consultants tiureau, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article cannot be reproduced for any purpose whatsoever without permission of the publisher. A copy of this article is available from the publisher for $15.00. - - 183 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 method. It is sufficient to point out that the weighted-average increase in the corn harvest for the 1968- 1971 period was 400 kg/ha (or 12%). In 1972, when over 50,000 ha were planted, 550 tons of seed were irradiated during the spring planting season in 12 different areas of the Republic. The report pointed out that, in the light of planting norms and of the price of commercial seed corn, operation of the Kolos unit for 1 h will bring a farm more than 1,000 rubles of profit, and by the end of the first season the unit will have paid for itself. There are five Kolos units operating in Moldavia today. The conclusion of the report indicated the prospects for further incorporating this method into Moldavian agriculture starting in 1973, using, as examples, corn, sunflowers, and sugar beets. The level of present investigations on the preplanting irradiation of seeds was discussed by N. M. Berezina (Institute of Biophysics of the Academy of Sciences of the USSR). In her survey of Soviet and foreign studies, she spoke of the role of various factors influencing the reproducibility of the stimulation effect and noted that the existence of a radiation technique that ensures uniform irradiation conditions (dose rate, temperature, degree of nonuniformity of irradiation), together with the modifying factors that have been studied and a number of environmental factors, determines the reproducibility of the results. She pointed out that the preplanting irradiation of seeds, as an agricultural method which does not preclude the utilization of a whole complex of agrotechnical measures, may be regarded as an additional reserve tech- nique for increasing the output of agricultural crops. The data obtained by Soviet researchers are now being confirmed by foreign authors. In a report by D. A. Kaushanskii (Moscow) entitled "The development of a new radiation technique for agricultural production," it was stated that, at the initiative of the State Committee on the Utilization of Atomic Energy, a number of gamma irradiating units (1VERKh-y-100, RKh-y-30, Issledovatel' units, RKhM-y-20 multichamber units, and others) had gone into industrial production and were being delivered to organizations by the All-Union Isotope Society. The author discussed in detail the problems involved in establishing a complex of industrially produced mobile gamma units for the preplanting irradiation of seeds (Kolos, Universal, Kolos-5, and Stimulyator). The resulting complex will make it posSible in the near future not only to carry out extensive production tests of this new agricultural technique over large areas, under various soil and climate conditions, for different kinds of seeds (both loose-grained and non-loose- grained) at seeding norms of 0.1-300 kg/ha, but also to begin immediately to incorporate it into agricul- ture. The report also gave data on the Genetik experimental?industrial gamma unit, designed for sexually sterilizing insect pests at various stages of their development under the conditions prevailing in biofactories, and on the Dezinsektor mobile gamma unit. The possibilities of using the Sterilizator unit (volume 60 liters, dose rate 1.6-1.7 Mrad/h) in agricultural production (for increasing the storage life of fruits and berries and for the sterilization of feed, hides, wool, etc.) were considered. The report discussed some characteristics of the developments of radiation technology in the USSR and elsewhere and noted that today the scientific groundwork is being laid for the establishment of a new field of' agricultural machine design ? the design of agricultural radiation machinery. A report on the results of the use of Kolos units in 1970-1972 in the Pavlodar region of the Kazakh SSR was delivered by Yu. A. Martemlyanov. He noted that under the conditions of the Pavlodar region, preplanting irradiation of seeds makes it possible to increase wheat yields by 10%, buckwheat by 16-17%, millet by 15%, sunflowers by 15-20%, and corn silage by 10-12%. In 1971 the profit resulting from the use of a single Kolos unit was 84,000 rubles, and it was expected that the use of two units in 1972 would bring a profit of about 200,000 to 250,000 rubles. The Pavlodar region is the site of the country's first radiation- technology station (RTS), designed to provide the collective farms and state farms of the region with radia- tion-technique services. A number of reports were devoted to the results of seed irradiation in the Kirgiz SSR (A. S. Sultanbaev, L. A. Sergeeva), the Belorussian SSR (Yu. M. Vaninskaya), the Latvian SSR (A. T. Miller), the Leningrad region, and other areas of the country. The use of atomic energy in various fields of agriculture was discussed in survey reports in the section headed by D. M. Grodzinskii (general problems of agricultural radiobiology), A. T. Miller (pre- planting irradiation of seeds), V. G. Semin (radiation and genetics selection), V. V. Rachinskii (radiation methods, instruments, and irradiation technology), A. A. Nichiporovich (isotopes and irradiation in plant physiology), and others. The participants in the Conference familiarized themselves with the new radiation technology used at the M. V. Frunze Agricultural Institute of Kishinev (industrially produced Kolos LMB-y-IM , and GUBE- 4000 units) and also visited the Moldavian Institute of Irrigated Agriculture. 184 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 FIFTH ALL-UNION CONFERENCE ON THE PHYSICS OF ELECTRON AND ATOM COLLISIONS V. B. Leonas The regularly scheduled All-Union conference on the physics of electron and atom collisions was held at Uzhgorod, September 19-23, 1972. A numerous group of scientists from the socialist countries took part in the deliberations of the conference. The conference paid homage to the memory of the recently deceased Professor N. V. Fedorenko, with whose name is indissolubly linked the founding of the Soviet school of the physics of electron and atom collisions, today generally acknowledged as one of the prominent trends in physics research. The conference surveyed progress achieved in this vigorously developing branch of plasma physics over the period elasped since the fourth conference (Riga, 1970). Until comparatively recently, the efforts of research scientists have been focused on the study of effects accompanying collisions of high-energy particles (1 keV), which has been associated with the problem of radiation effects and problems involving materialization of the first stages in thermonuclear research programs. In recent years, with the progressive conquest and study of outer space, the avail- ability and applications of high-power gas lasers, magnetohydrodynamics as a full-fledged low-power source, advances in chemical technology, and so forth, there has also been a concomitant and impres- sive expansion of research in the field of low-energy collisions. A total of 281 papers were presented at the conference.* The conference deliberations took place in plenary sessions and at panel sessions. Review papers delivered at the plenary sessions provided an overview of the general state of research in the physics of particle collisions. Reports by E. E. Nikitin surveyed opportunities associated with inter- pretations of measurements of differential cross sections for elastic scattering, and inelastic scattering. Decoding the specific structure of the experimental dependence arrived at makes it possible to restore, quite precisely, the variation of the term-potentials of the interactions (by analogy with molecular spectroscopy, this led to the apparance of the term "collisional spectroscopy"). Some particularly intriguing possibilities have been opened up by analysis of data on inelastic scattering due to what has been termed intersection or crossing of terms. The theory of atomic collisions has long had at its disposal a mathematical tool-kit adequate for quantitative descriptions of such scattering, but this apparatus has not been put to practical use because of the lack of a reliable experiment. The development of experimental techniques has now rendered possible a comparison of theoretical predictions and measurements in this area, and has made it possible to determine quantitatively parameters Which are crucial for the inelastic scattering process. This in turn makes it possible to establish the overall regularities and patterns in inelastic transitions. The problem of how to exert control over a real chemical process (over its rate and direction) under conditions where the process is being intensified by a powerful activating agent (radiation or laser) is closely associated with our level of knowledge on the mechanism underlying the process, and on laws governing some distinct stages of the process. Until recently, all of our concepts of elementary reactions in gases has been based on comparisons of macroscopic reaction rates measured empirically and those calculated on the basis of a specific model. The inevitable statistical averaging of the effects of distinct collisions in counts of the observable macroscopic yield of reaction products generally tends to blur out the distinctions between models. This state of affairs is unsatisfactory, even from the standpoint of the prospective utiliza- tion of chemical processes in the generation of laser emission. In that sense, we see some unique *Abstracts of the papers presented have been published under separate cover. Translated from Atorrinaya Energiya, Vol. 34, No. 2, pp. 140-141, February, 1973. o 1973 Consultants figreau, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article cannot be reproduced for any purpose whatsoever without permission of the publisher. A copy of this article is available from the publisher for $15.00. 185 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 possibilities and opportunities being opened up by research on chemical reactions with the aid of the method of colliding beams. Highly detailed information on the probability, dynamics, and energetics of the elemen- tary collision process involving chemical transformation of partners has been obtained successfully in that research. The applied value of such research is quite evident, and the investigations are of inestimable value in terms of the development of a reliable theory to account for the elementary processes. The results of beam investigations of elementary atomic ? molecular processes typical of collisions in a low-temperature plasma was the subject of a report submitted by V. I. Gol'danskii, V. B. Leonas, and L. Yu. Rusin. In a manner similar to the chemical processes, molecular transport processes, excitation of internal degrees of freedom of molecules in gases, and such had been studied previously only on a macroscopic level. Successful elaboration of a reliable theory accounting for elementary atomic?molec- ular processes, and possibilities of subsequent quantitative applications of the theory, must be related to the direct information that can be secured in beam experiments on the potentials of pair interaction, and on the probabilities of translational ?vibrational (and rotational) transitions. The new approach to the study of elementary atomic?molecular processes (elastic scattering, energy exchange, chemical transformations) does not entail simply replacement of some methods by other methods; the purpose is to secure such experimental information as to make it possible to greatly improve the "pre- dictability" of the theory called for by the demands of sophisticated industry of the current epoch. A paper presented by G. F. Drukarev was devoted to these "second-generation" experimental problems. Even the most perfectly conceived and worked-out experiments cannot yield complete information on collisional processes, because of the averaging effect due to the spectrum of spin states and due to the orientations of the interacting particles; this effect cannot yet be completely eliminated. The second-generation experi- ments are being devised to surmount this hurdle, and the report discussed prospective ways of achieving "polarized" collisions. A paper by V. V. Titov demonstrated two aspects of research investigations on atomic collisions. On the one hand, the paper showed the possibility and fruitfulness of utilizing the concept of pair collisions in the problem dealing with the motion of a high-energy particles in a periodic structure of the atomic lattice type, and on the other hand, it was clearly demonstrated how the procedure of a purely physical experiment can become the basis of a new technological process for fabricating solid-state electronic de- vices with prespecified parameters. The research done at Uzhgorod on optical excitation cross sections in collisions involving electrons, ions, and atoms came through in some of the papers presented at the conference. A detailed study of excitation of inner and outer envelopes of atoms was covered by papers submitted by staff scientists of the A. F. Ioffe Physicotechnical Institute. A novel procedure for investigating the energy levels of highly excited negative ions was also devised and is now in use. There was considerable interest manifested in a report on a large-scale facility for investigating chemical reactions in intersecting beams that has been built at the institute of Chemical Physics of the Academy of Sciences of the USSR. Consequently, the conference was a demonstration of the qualitative and quantitative expansion of research in this area; the growth and high scientific level of the theoretical research were again put in evidence. Some shortcomings also came to light. Given the generally high stress put on theoretical re- search, there is unjustifiably scant attention being given to analysis of collisions of atoms and molecules at low energies. The data adduced on processes occurring at thermal energies are generally acquired on the basis of measurements of macroscopic properties, and are converted into cross sections of micro- scopic processes only with the observance of certain assumptions (some of which are quite open to ques- tion). The insufficient attention given to the development of beam experiments in the range of low energies was reflected in the discussion on techniques and equipment. The next All-Union conference on this topic is scheduled for 1975. 186 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 SOVIET ? SWEDISH SYMPOSIUM ON THE PHYSICS OF THERMAL AND FAST REACTORS I. D. Rakhitin The first Soviet -Swedish joint symposium on the physics of thermal reactors and fast reactors was held September 11-5, 1972, at Dubna. The renowned Swedish specialists I. Jung, B. Pershagen, E. Hel- lstrand, R. Persson, E. Tenerts, and others took part in the work of the symposium, and subsequently visited leading Soviet scientific research institutes. Over thirty papers were heard and discussed, including about twelve delivered by Soviet experts. The report by V. T. Rudenko describes the IBR fast pulsed reactor, and problems solved through the use and operation of that reactor at JINR. The study of the physical features of fast reactors with BFS physical assemblies was the subject of reports by Yu. A. Kazanskii and V. A. Dulin. Theoretical and ex- perimental aspects of the physics of thermal reactors were reflected in reports by I. N. Aborina, V. I. Naumov, and colleagues. Various topics in the calculations and design of fast reactors, working out requirements for nuclear physics data, compiling libraries of nuclear data and reactor programs, were addressed in remarks by R. I. Nikol'skii, S. M. Zaritskii, I. P. Markelov, and M. N. Zizin. Soviet reports on the most urgent topics in the mathematical theory of nuclear reactors, development of new methods for solving reactor equations, and the development of concepts in reactor theory, met with great interest (such reports were presented by V. V. Khromov, I. D. Rakitin, V. N. Artamkin, A. V. Voronkov, B. P. Kochurov, E. S. Tsapelkin, and N. I. Laletin). Swedish specialists delivered some informative reports. The head of the Reactor design division, E. Tenerts, presented an account of reactor physics re- search problems and developments in design and determination of the characteristics of thermal reactor cores. He reported that old-standing problems in reactor physics, such as the calculation of critical mass, for example, or calculations of neutron flux, of reactivity coefficients, of the reactivity balance and burnup, are now being solved with greater accuracy than actually required for reactor operation. Today's problems are a combination of heat transfer, hydraulics, neutron physics, reactor control, and economics. Reactor physics comprises a component part of reactor technology, and all the problems relating to it have to be studied simultaneously. General problems pertaining to the development of Sweden's nuclear power industry and requirements applicable to reactor physics are covered in a report by B. Pershagen. Until the mid-Sixties, attention had been centered on pressure vessel type heavy-water reactors. The first such reactor built at Agesta was started up in 1963. Its thermal power output level stood at about 80 MW. Construction of a straight-flow boiling heavy water reactor at Marviken, with a rating of 140 MW(e), was cut short in 1970 because of the competition by ordinary-water boiling-water reactors (BWR). Construction work was begun, in 1965, on the first full-scale water-cooled water-moderated boiling- water reactor, BWR type, rated 440 MW(e), at Oskarshamn. This reactor was started up in August 1971, and went on the line producing electric power in February 1972. The nuclear power developmental outlook in Sweden is reflected in the following figures: Translated from Atomnaya Energiya, Vol. 34, No. 2, pp. 141-143, February, 1973. 0 1975 Consultants Bureau, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article cannot be reproduced for any purpose whatsoever without permission of the publisher. A copy of this article is available from the publisher for $15.00. 187 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Year Power station output, Nuclear power station fractional MW (e) contribution to total national elec- tric power production, % 1975 2600 15 1980 8600 30 1985 16,500 50 1990 25,500 60 The construction of industrial fast breeders is scheduled for no earlier than the decade 1980-1990 in Sweden. The core of the Agesta heavy-water reactor was designed on the basis of a simple two-group proce- dure, with experimental verification using the ZEBRA exponential assembly. The calculations were found to agree closely with experiment. More rigorous design techniques were developed for the Marviken reactor. For example, a com- putational program for FLEF cells was compiled on the basis of a solution of the kinetic many-group equa- tion in integral form. Several many-group two-dimensional and three-dimensional programs based on a heterogeneous me- thod of the source ?sink type, and written in FORTRAN language, were devised to the aid the study of macrodistributions of neutron fields in heavy-water reactors. Extensive research on the physics of BWR and PWR type ordinary-water reactors is underway in Sweden. Computational techniques were verified both during the startup of the Oskarshamn-1 reactor and in the performance of the KRITZ high-temperature assembly (R. Persson). One of the outstanding results of these search efforts was the pinpointing of systematic discrepancies between the theoretically predicted and experimental values of the temperature coefficient of reactivity. At the present time, a program for aiding studies of lattices with fuel in the form of plutonium dioxide is being worked out. The plutonium fuel elements were obtained from USAEC. In the design techniques developed in Sweden, attention is centered on predictions of the characteris- tics of reactors while in operation, and optimization of fuel reloading, as well as on the study of the plutoni- um cycle in thermal reactors. The BUXY two-dimensional many-group program (M. Edenius), used in the preparation of macroscopic constants for diffusional calculations of power distribution fields in large power reactors by the POLCA program, based on a three-dimensional grid network one-group solution of the dif- fusion equation, is used on the widest scale for calculations of lattice parameters. This BUXY program incorporates thermohydraulic calculations of two-phase flow, and carries out iterations in terms of coolant density as a function of reactor output power, with xenon poisoning taken into consideration. Startup operations and beginnings of reactor operation yielded rich information, in the case of the Oskarshamn-1 reactor, useful in verifyingthe BUXY ? POLCA computational system, including data on reactivity, field distributions, and the effects of control rods. As E. Tenerts pointed out, the agreement between calculations and experiment was much better than expected. The study of fast reactor physics was begun in Sweden in 1964, with the startup of the FRO critical assembly at Studsvik (loading of 600 kg 20%-enriched uranium metal). A cycle of major experiments was staged with this fuel assembly (E. Hellstrand). In this way the effective cross sections of ten different isotopes in fission products in three different spectra of a fast reactor were determined, as well as the mean number of fast fission neutrons I, for U235 and Pu239. The calculated and empirical values agreed within the limits of error of the experiment. Finally, experiments were staged to aid investigation of reaction rates in different configurations of breeding blankets. Investigations of the Doppler effect and comparison of those data and,the theoretical data are dealt with in a report by H. Heggblum. The results of this comparison are fully satisfactory, if we bear in mind heterogeneous effects in experimental specimens, as well as the fine structure of the spectrum and the overlapping resonances. Extensive work on estimates and compilation of nuclear data, a very timely topic at this time, is being done in Sweden. 188 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 In the SPENG program, the neutron spectrum is computed in 2000 energy groups, for a finite homo- geneous mixture, and effective cross sections and group constants are worked out for any group decomposi- tion whatever. For those groups where resonance self-shielding and overlapping resonances are essential, the averaged cross sections are computed according to the DORIX program as a function of the temperature and a function of the effective potential cross section. The report by H. Heggblum presents a method for determining estimated neutron data with simultaneous consideration of a large number (51) of macroscopic characteristics obtained in work on fast reactors (31 critical assemblies). It is interesting to note that the fission cross section of U235 and the capture cross section of U238 are much lower than the data available in the famous ENDF/B-11 library, in the range of energies of greatest importance for fast reactors. Starting 1966, design projects have been underway in Sweden on three distinct types of fast breeders rated at 1000 MW(e), with sodium, gas, and steam as coolants, and with attention focused on sodium- cooled fast reactors. It is proposed that the initial construction work on an industrial fast breeder get under way not earlier than the 1980's. Work on the development of computational techniques and programs for fast reactors was reported by K. Jirlov. The basic purpose of the system of programs is to determine the appropriate geometry and composition of the core, as well as the effective fuel cycle for conditions where the percentage burnup and the specific output power in the core and in the breeding blanket will not surpass reasonable limits. In conclusion, we may note that the meeting between the Soviet and Swedish scientists was most fruitful. The understanding in effect calls for a return Swedish?Soviet symposium to be held in Sweden during 1973, to discuss engineering topics relating to nuclear reactor safety. 189 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 Declassified and Approved For Release 2013/09/15: CIA-RDP10-02196R000400010002-8 BRIEF COMMUNICATIONS The second CERN school on digital computer processing of experimental data was held September 10-24 in Austria. Attending the school session were young physicists and computing scientists from 19 European countries, including two from the USSR. The lectures delivered by scientists from CERN member nations encompassed a wide range of topics; translation procedure; the use of desktop computers in physics; system programming; use of large computing systems. Experimental physicists were most interested in the second round of lectures. These included a particularly interesting lecture course given by W. Zacharow (Britain) developing the general principles of the design and software of desktop computer systems for on-line processing of experimental data. An example of a well-conceived and organized system with on-line computing equipment is the CERN Omega-project, a general-purpose magnetic spectrometer capable of recording and analyzing the most widely varied processes in high-energy physics (R. Russell). An arrangement for investigations of nuclear reactions at intermediate energies (BOL) has been devised at the Amsterdam Nuclear Research Institute for research at the synchrocyclotron (J. Obersky). , The recording system operates with two PDP-8 computers, which are in turn hooked up to an EL-X8 ma- chine. One of the lectures was devoted to on-borad computers of satellites (M. A. Perrie, Netherlands). R. Kaiser (CERN) and J. Schraml (West Germany)demonsfratedthe possibilities of utilizing com- puters in the control of accelerators and radio telescopes. One round of lectures (F. James, G. Wind, CERN) was devoted to general topics in the mathematical processing of large blocks of information. In particular, G. Wind presented an intriguing method of geometrical restoration of tracks in the presence of large statistics, such that machine memory capacity could be greatly conserved by utilizing precomputed coefficients. On the whole, the materials presented at the CERN school on computer processing of experimental physics data were of great interest. In line with the terms of an agreement of collaboration in the field of peaceful uses of atomic energy, contracted between the GKAE SSSR and the Canadian state agency Atomic Energy of Canada, a delegation of Canadian specialists on nuclear reactor coolants, headed by P. J. Dean, visited the Soviet Union September 18-28, 1972. The delegation members vistited the I. V. Kurchatov Institute of Atomic Energy, the G. M. Krzhizh- anovskii Power Institute, the Power Physics Institute at Obninsk, the Thermal Physics Institute of the Siberian Division of the Academy of Sciences of the USSR, the Moscow Power Institute, and also the V. I. Lenin Atomic Reactor Scientific Research Institute [NIIAR] in Dimitrovgrad. The interest of the delegation was focused on the following topics: heat removal when using boiling water as reactor coolant; chemistry of the water coolant, i.e., how the required composition and the necessary quantity of salts can be sustained in the coolant, as well as the required amounts of oxygen and hydrogen; corrosion of the surfaces of loops and entrainment of corrosion productions in the loop stream; activation of corrosion products and deposition of corrosion products on the loop surfaces; the radiation environment and repair and maintenance of process equipment. Soviet scientists and specialists delivered reports on these topics. For their part, the Canadian specialists gave accounts of work in progress in Canada on the investigation of burnout and postburnout phenomena and conditions, and also on the use of organic coolants in reactors. Translated from Atomnaya Energiya, Vol.34, No. 2, pp. 143-144, February, 1973. 0 1973 Consultants Bureau, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article