长期低功率运行对压水堆CIPS风险的影响研究  

Research of Extended Low Power Operation Impact on PWR CIPS Risk

作　　者：金德升 田雅婷 冯英杰 阮天鸣 蒙舒祺 JIN Desheng;TIAN Yating;FENG Yingjie;RUAN Tianming;MENG Shuqi(China Nuclear Power Technology Research Institute,Shenzhen of Guangdong Prov.518000,China)

机构地区：[1]中广核研究院有限公司,广东深圳518000

出　　处：《核科学与工程》2022年第5期1004-1008,共5页Nuclear Science and Engineering

基　　金：国家自然科学基金(U20B0211,针对堆芯氧化腐蚀产物材料-热工-中子行为的多物理耦合机理);国家自然科学基金(52171085,模拟压水堆一回路冷却剂中燃料包壳管表面污垢沉积行为与机理研究)。

摘　　要：长期低功率运行(Extended Low Power Operation,ELPO)在压水堆(Pressurized Water Reactor,PWR)中具有广泛的实践经验,随着国内核电装机容量增加,为满足电网负荷不断变化的需求,越来越多的核电机组需面对日负荷跟踪或ELPO。大部分在运机组通过调整硼浓度来实现ELPO运行,ELPO期间主流体硼浓度升高、堆芯功率降低,这些变化会影响硼在燃料表面污垢(Chalk Rivers Unidentified Deposit,CRUD)中的析出,改变垢致轴向功率偏移(Crud Induced Power Shift,CIPS)程度。本文揭示了CIPS的根本原因,并采用子通道程序和污垢分析程序评估了某百万千瓦级PWR采用ELPO模式后的CIPS风险。计算结果表明,将堆芯功率下降至75%,CIPS风险降低;继续将堆芯功率下降至50%,CIPS风险略有升高,但仍低于满功率运行工况。研究结果为评估ELPO对CIPS的影响提供了数据支撑,同时也为控制CIPS风险提供了新的思路。Extended Low Power Operation(ELPO)has extensive practical experience in PWR(Pressurized Water Reactor).With the increase of installed capacity of nuclear power in China,more and more nuclear power units need to face daily load tracking or ELPO to meet the demand of power grid load.Most in-service units realize ELPO operation by adjusting boron concentration.During ELPO,the boron concentration in bulk coolant increases while the core power decreases.These changes will affect the precipitation of boron in fuel CRUD(Chalk Rivers Unidentified Deposit)and change the degree of CIPS(Crud Induced Power Shift).This paper reveals the root cause of CIPS,and evaluates the CIPS risk of a PWR after adopting ELPO mode by using sub channel code and CRUD analysis procedure.The calculation results show that the risk of CIPS is reduced by reducing the core power to 75%;keep reducing the core power to 50%,the CIPS risk increases slightly,but it is still lower than the full power operation condition.The research results provide data support for evaluating the impact of ELPO on CIPS,and also provide a new solution for controlling PWR CIPS risk.

关 键 词：长期低功率运行 压水堆 污垢 垢致轴向功率偏移 

分 类 号：TL364[核科学技术—核技术及应用]