Improvement of few-group cross-section generation in fast reactor analysis system SARAX

摘要

For better accuracy, the few-group cross-section generation module, named TULIP, in the SARAX code system was further improved. In the new TULIP, the pure deterministic method was used for the spectrum calculation and self-shielding treatment. The improvements contained two parts. One was the method for resonance treatments in the unresolved resonance region. The probability table method was adopted and the self-shielding factors for different reaction types were distinguished. The background cross-section interpolation points of major actinides were refined for the Bondarenko interpolation. These techniques significantly improved the accuracy of self-shielded cross-sections and contributed to better Doppler constant calculation. The other improvement was the method of Energy collapsing SuPer-Homogenization technique for the group condensation. It preserved the reaction rates conservation in the multigroup-fewgroup equivalence and improved the accuracy in the strong heterogeneous problems. Several numerical and experimental benchmarks have been done to test the improvements. The results showed that the accuracy of homogenized cross-sections, k-infinity and Doppler constant in subassembly calculation was significantly improved, also for the k-effective, power distribution and reaction rate distribution in the core calculation. (C) 2019 Elsevier Ltd. All rights reserved.