不同核评价数据库中Pb和Bi的截面对铅基快堆k_(eff)的影响

铅基快堆是GIF官方发布的第四代核能系统堆型之一,不同的核评价数据库中铅截面的较大差别会影响铅基快堆物理设计计算的准确性。本文利用国际上最新发布的核评价数据库JENDL-4.0、JEFF-3.2、ENDF/B-Ⅶ.0和BROND-3.1,制作了关键核素Pb、Bi的连续点截面,利用国际基准题评价手册中的PMF035和国际原子能机构发布的铅基快堆RBEC-M基准题以及cosRMC程序,对Pb和Bi的截面对系统有效增殖因数的影响进行了详细研究。对于PMF035带Pb反射层的临界基准题,上述所有核数据库的新版本较旧版本的计算偏差均有所减小,其中BROND的改善最为明显。对于RBEC-M基准题,使用ENDF/B-Ⅶ.0核数据库的计算结果与基准报告中结果符合较好;使用上述其他新版本数据库中截面数据替换计算结果表明,采用不同库中的Pb、Bi截面数据会使计算结果出现不同的偏差,其中,JENDL-4.0中Pb截面对计算结果的影响较Bi截面的影响大。

Effect of Pb and Bi Cross Section from Different Nuclear Evaluation Databases on keff of LFR

LFR is one of the advanced reactor concepts which were selected for generation-Ⅳreactors. The cross section data of Pb used for LFR calculation in different databases are quite different, which could have bad impact on the accuracy of the design. Continuous cross section data of the key nuclides Pb and Bi were produced according to the latest international nuclear evaluation database JENDL 4.0, JEFF 3.2, ENDF/B-Ⅶ.0 and BROND-3.1. The effects of Pb and Bi cross sections on the effective multiplication factor were studied by using cosRMC code, the PMF035 in the international benchmarking manual and RBEC-M benchmark published by the International Atomic Energy Agency (IAEA). For the PMF035 benchmark with Pb reflective layer, the calculation deviations are less than before by using all of above nuclear databases, and the improvement of BROND is the most obvious. For the RBEC-M benchmark, the calculation results using the ENDF/B-Ⅶ.0 database are in good agreement with the results of benchmark report. The calculation results using replacement data in the other new version databases show that data of Pb and Bi from different databases can lead to different deviations in the results. The influence of Pb cross section in JENDL-4.0 on the deviation of the results is larger than that of Bi cross section.