燃料多次通过堆芯模式下不确定性传播的方法研究

项目名称： 燃料多次通过堆芯模式下不确定性传播的方法研究

项目编号： No.11505102

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 郭炯

作者单位： 清华大学

项目金额： 23万元

中文摘要： 反应堆系统计算的不确定性分析是研究热点。核截面、堆芯物质组成等存在不确定性，带来增殖因子、安全裕量等的计算不确定性。常采用不确定性传播方法，在每个计算环节考虑自身的不确定性因素，并把不确定性结果传播到下一个计算环节，由此得到综合结果。这适合于燃料元件固定位置的常规反应堆。本课题参与国际上不确定性分析合作项目，发现不确定性分析还处于早期探索阶段。球床高温堆运行时燃料球多次通过堆芯，燃料空间位置的变化使得物理计算、热工计算、燃耗计算与球流运动耦合在一起，物理计算的不确定性、燃耗计算的不确定性，最终通过球流运动又返回到物理计算这个源头，形成闭环反馈，传播不下去了。这需要新的不确定性传播思路。计划采用从源头扰动黑箱模型的方法来定量分析高温堆的不确定性的大小，与燃料位置固定的分析结果作为对比，分析燃料多次通过情况下不确定性传播特性，探索新的方法框架。开发的方法、软件和成果预计都具有创新性。

中文关键词： 多次通过堆芯；不确定性传播；高温气冷堆；核截面；闭环

英文摘要： The uncertainty analysis is the research focus of the reactor system calculation.Uncertainty of nuclear cross section and reactor core material causes the calculation uncertainty of multiplication factor and safety allowance. Propagation method is often applied for the uncertainty analysis, In every calculation procedure, the method considers their own uncertainty, propagate the uncertainty results to the next procedure and then gets the synthetic results. This method is suitable for the conventional reactor whose fuel elements are in the fixed position. This research participated in the international cooperation project of uncertainty analysis.The uncertainty analysis is still in the early exploration stage. The spherical fuel elements multiple pass through the reactor core in the operation of the pebble bed high temperature reactor. The physical calculation, thermal calculation, burnup calculation are coupled together because of the change of the fuel elements position.The uncertainty of physical calculation and burnup calculation finally return to the physical calculation because of the fuel movement, forming a closed loop feedback. So the new idea is required to analyze the uncertainty in this propagation. This research plans to adopt the disturbance black-box model from source to quantitatively analyze the uncertainty of high temperature reactor and then compares the results with the results when the fuel position is fixed. This research plans to analyze the uncertainty propagation when the fuel elements pass through the reactor core several times and explore a new method framework.The development of method, software and the anticipated results are all innovative.

英文关键词： multiple pass through core;uncertainty propagation;HTGR;nuclear cross section;closed loop