熔盐冷却球床堆核数据不确定性对K_∞的影响  

Effect of Nuclear Data Uncertainty on K_∞ in Molten Salt Cooled Pebble Bed Reactor

作　　者：杨群[1] 邹杨[1] 于世和[1] 戴叶[1] 严睿[1] 余笑寒[1] 徐洪杰[1] 

机构地区：[1]中国科学院上海应用物理研究所,上海201800

出　　处：《原子能科学技术》2013年第B12期678-682,共5页Atomic Energy Science and Technology

摘　　要：熔盐冷却球床堆是当前国际上一种先进的研究堆型,其冷却剂及燃料元件材料均不同于发展较成熟的轻水堆,因此对核数据不确定性及由此引起的K∞不确定度进行评估十分必要。利用目前国际上常采用的敏感性和不确定性分析软件可实现上述目的。对单球模型分析结果表明,核数据不确定性引起的K∞不确定度约0.6%。7 Li(n,γ)反应截面不确定度约14.7%,对应的K∞不确定度最大;反应截面不确定性紧随其后的是燃料球石墨、包覆颗粒C及F等。由于235 U和238 U反应最敏感,因此对应的K∞不确定度仅次于7 Li。对于熔盐冷却球床堆,核数据精确性特别是7 Li(n,γ)反应截面需进一步提高。The molten salt cooled pebble bed reactor is one of the advanced reactors, and it is necessary to estimate the nuclear data uncertainty and consequent K∞ uncertainty because the coolant material and fuel element material are different from those of well developed light water reactors. This can be achieved by the most often used sensitivity and uncertainty analysis software. The results from single pebble model show that the K∞, uncertainty due to nuclear data is about 0.6%. The 7Li（n, y） cross section uncertainty is about 14.7% and K∞, uncertainty is the largest. The cross section uncertainty of graphite in pebble, C and F in coated fuel particle is just smaller. Because 235U and ^238U reaction is the most sensitive to K∞, the corresponding K∞ uncertainty is second only to 7 Li. Therefore, the accuracy of nuclear data needs to be improved in the molten salt cooled pebble bed reactor, especially for the 7Li（n, γ） cross section.

关 键 词：熔盐冷却球床堆 核数据 不确定度 敏感性 

分 类 号：TL329[核科学技术—核技术及应用]