MCNP程序用热中子散射数据制作和检验

基于ENDF/B-Ⅶ.0评价库，以前已陆续研制了可供MCNP程序使用的连续截面库，以及多套多个温度、多组邦达连柯背景截面修正的多群参数库。本文采用NJOY程序以及ENDF/B-Ⅶ.0评价库热散射子库，完成了MCNP程序使用热中子散射数据库S(α，β)的制作和检验。比较了自制库与MCNP自带基于ENDF/B-Ⅵ版热散射数据库(sab2002)，对改进较明显的重要介质“轻水中氢”和“重水中氘”给出了分析说明。通过48个基准装置k_eff计算结果可看出，MCNP程序自带热中子散射库sab2002与自制库thb70计算的k_eff整体上偏差不大，k_eff平均偏差约65pcm。

Generating and Validation of Thermal Neutron Scattering Library for MCNP

A continuous neutron transport library for MCNP and several temperature-dependent multigroup cross section libraries with Bondarenko self-shielded factors based on ENDF/B-Ⅶ.0 were generated in former work. In the work the thermal S(α, β) tables for MCNP code were converted from the thermal neutron scattering sublibrary of ENDF/B-Ⅶ.0 using NJOY program. The available thermal S(α, β) library named sab2002 (from ENDF/B-Ⅵ) released with MCNP were investigated and compared with the self-produced library thb70, and some significant improvements of important medias, such as H in H₂O and D in D₂O, were presented. Forty-eight critical benchmark models were selected to calculate the k_eff using sab2002 and thb70, respectively. The results show that there is a not too much difference (65 pcm averagely) between the two libraries.