钍增殖熔盐堆不同燃耗核数据不确定度分析

Analysis of Uncertainty of k_(eff) to Nuclear Data in Thorium Molten Salt Breeder Reactor with Burnup

本文利用开发的耦合模块,将SCALE程序中的TRITON和TSUNAMI-3D模块相结合,针对1GWth钍增殖熔盐堆开展不同燃耗时期核数据引起的k_(eff)不确定度分析。结果表明:随着燃耗的增加,核数据引起的keff不确定度由0.49%增大到0.55%。初始时刻对k_(eff)不确定度影响最大的反应截面是232 Th(n,γ)(约0.35%),其次是233 U(n,f)和7 Li(n,γ)。随着燃耗的增加,^(135)Xe(n,γ)、^(143)Nd(n,γ)对k_(eff)不确定度的影响逐渐显著。各反应灵敏度系数分析表明,^(232)Th(n,γ)、^(233)U(n,f)和~7Li(n,γ)截面数据对k_(eff)不确定度影响较大,需重点改进。上述关键反应在0.02~0.5eV敏感性较强,需重点关注。

Based on a 1 GWth thorium molten salt breeder reactor （TMSBR）, uncertainty of keff to nuclear data was analyzed using the TRITON and TSUNAMI-3D mod- ules of SCALE. The results show that uncertainty of keff to nuclear data increases from 0.49% to 0.55% with burnup time. At the beginning of life （BOL）, 232Th（n,γ） cross section is the largest contributor to the keff uncertainty, which is about 0.35%, followed by the contributions from 233U（n, γ） and 7Li（n,γ） cross sections. With the increase of burnup, the effects of 135 Xe（n, γ） and 143 Nd（n,γ） cross sections on the keff uncertainty become more increasingly significant. The analysis for sensitivity coefficient shows that the cross sections for 232Th（n,γ）, z33U（n,γ） and 7Li（n,γ） have more significant impacts on the keff uncertainty, especially at at the neutron energy range of 0. 02-0.5 eV, whichshould therefore be improved.