%A"Matausek, M V" %A"Bosevski, T [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Yugoslavia)]" %D1965 %I; %2 %J[] %K22 GENERAL STUDIES OF NUCLEAR REACTORS, CROSS SECTIONS, MULTIGROUP THEORY, NEUTRON FLUX, NEUTRON SPECTRA, P3-APPROXIMATION, REACTOR CELLS, SLOW NEUTRONS, SPHERICAL HARMONICS METHOD %PMedium: ED; Size: 21 pages %TThermal neutron group constants in monoatomic-gas approximation %XTo solve the problem of space-energy neutron distribution in an elementary reactor cell, a combination of the multigroup procedure and the P{sub 3} approximation of the spherical harmonics method was chosen. The calculation was divided into two independent parts: the first part was to provide multigroup constants which serve as input data for the second part - the determination of the slow neutron spectra. In the present report only the first part of the problem will be discussed. The velocity dependence of cross-sections and scattering function in thermal range was interpreted by the monoatomic-gas model. A digital computer program was developed for the evaluation of the group values for these quantities (author00. %0Miscellaneous %NINIS-RS-0085; IBK-374;TRN: RS06RA102013807 %1 %CSerbia %Rhttps://doi.org/ TRN: RS06RA102013807 INIS %GEnglish