基于不确定性与敏感性分析的FA300燃料棒燃耗限值研究

Research on FA300 Fuel Rod Burnup Limit Based on Uncertainty and Sensitivity Analysis

燃耗限值对于燃料棒的安全使用和设计改进均有重要意义,而FA300燃料棒的燃耗限值尚未有系统研究。不确定性与敏感性分析方法是燃耗限值研究的基础,工程上常用的极值分析法、蒙特卡罗法等均难以全面反映燃料棒性能分析中的不确定性与敏感性。本工作采用基于人工神经网络的响应面方法,对相应数学模型进行显式重构,在响应面上进行抽样统计获得不确定性信息;而对于特定形式的人工神经网络,通过简单的代数运算获得敏感性信息。基于这一方法的研究表明,FA300燃料棒的极限准则为包壳腐蚀及包壳应变。结合秦山一期加深燃耗组件随堆考验的检测结果,以及国际上相关使用经验,从燃料性能分析的角度给出FA300燃料棒的燃耗限值为55 000MW·d/tU。

Burnup limit is important for the safe use and design improvement of fuel rod . Burnup limit of FA300 fuel rod was not studied before . Uncertainty and sensitivity analysis was the basis of burnup limit research . Current methods such as bounding method ,Monte Carlo method ,etc .are hard to represent the information of uncertainty and sensitivity in analyzing fuel rod characteristics . With ANN （artificial neural network ） based response surface method , mathematic model was reconstructed in explicit form .Then uncertainty information was obtained by sampling on the response surface .As to some special form of ANN model ,sensitivity information was obtained with simple algebraic calculation . The results show that corrosion and strain of the cladding are the most limiting criteria for FA 300 fuel rod . Compared to the post irradiation examination data of lead assembly irradiated in Qinshan Phase-Ⅰ NPP and other related experience ,burnup limit of FA300 fuel rod is 55 000 MW？d/tU .