GENERATION OF 69-GROUP CROSS SECTION LIBRARY BASED ON JEF DATA FOR TRIGA REACTOR CALCULATIONS AND ITS VALIDATION BY ANALYZING THE BENCHMARK LATTICES OF THERMAL REACTORS

摘要

A new executable, identified as NJOY99.0 has been created to generate the 69-group cross-section library for the reactor lattice transport code WIMS. The new code incorporates modifications in the WIMSR module of NJOY to generate the 69-group library, which will be used for TRIGA reactor calculations. The basic evaluated nuclear data file JEF-2.2 was used to generate the 69-group cross-section library in WIMS format. The results for TRX-1, TRX-2, BAPL-1, BAPL-2, and BAPL-3 benchmarks obtained by using the generated 69-group cross-section library from JEF-2.2 were analyzed. The following integral parameters were considered for the validation of the 69-group library: finite medium effective multiplication factor (k_(eff)), Ratio of epithermal to thermal ~(238)U captures (p~(28)), Ratio of epithermal to thermal ~(235)U fission (8~(25)), Ratio of ~(238)U fission to~( 235)U fission (δ~(28)) and Ratio of ~(238)U captures to ~(235)U fissions (C~*). The TRX and BAPL benchmark lattices were modeled with optimized inputs, which were suggested in the final report of the WIMS Library Update Project (WLUP) Stage-I by Ravnik. The calculated results of the integral parameters of TRX and BAPL Benchmark Lattices obtained by using the new version of code WIMSD-5B were found to be in good agreement with the experimental values. Besides, The TRX and BAPL calculation results showed that JEF-2.2 is reliable for thermal reactor calculations and validated the 69-group library, which will be used for the neutronic calculation of the TRIGA Mark-II research reactor at AERE, Savar, Dhaka, Bangladesh.