Development of a standard data base for FBR core nuclear design; Analysis of JUPITER-I Experiments by the latest method

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A series of critical experiments for conventional two-zone homogeneous cores of 6 to 8 MWe-class LMFBR, JUPITER phase-I, were analyzed and evaluated using the latest analytical method, which had been established from the preceding numerous studies on fast reactor physics. The present work is a part of efforts to develop a standard data base for LMFBR core nuclear design at PNC. The analytical method and results are summarized as follows: (1)Analytical method (a)Nuclear data : 70-group fast reactor constant set JFS-3-J2(1989 edition) based on the Japanese Evaluated Nudear Data Library, version 2 (JENDL-2). (b)Cell calculation : plate stretch model, cell heterogeneity treatment by Tone's method and transport cross-sections weighted with neutron current. (c)Base core calculation : 18-group, three-dimensiona1 XYZ diffusion theory and Benoist's anisotropic diffusion coefficients. (d)Correction calculation : three-dimensional transport effect, mesh size effect, cell asymmetric effect and all master model effect etc. (2)Analytical results (a)The C.E (calculation/experiment) values of criticality agree quite well among seven cores (ZPPR-910D/2) and do not depend on the core volume or the number of control rod positions (CRP). (b)The C/E values of control rod worths increase gradually from the core center to the core edge positions in each core (511%). Those of reaction rate distributions also indicate similar spatial variations (25%), which is considered to be consistent with the C/E tendency of control rod worths. (c)The reaction rate ratios of C28/F49 and F25/49 give quite stable C/E values of 1.06 and 1.03, respectively. (d)The C/E values of sodium void reactivities are overestimated by +25% at core center region. The C/E dependence on void region size, which was pointed out in the past analyses, is found in the ZPPR-9 core, but not in the ZPPR-10 series. (e)The C/E dependence of 4% on the radial positions were found in sample ...