热工-化学-物理耦合的压水堆CIPS风险分析方法及应用  

A Thermal-chemical-physical Coupling Methodology for PWR CIPS Risk Assessment and Its Application

作　　者：周洲 胡友森 蒙舒祺 ZHOU Zhou;HU Yousen;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983-988,共6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：压水堆(Pressurized Water Reactor,PWR)一回路金属材料的腐蚀产物随着冷却剂流经堆芯,在燃料包壳表面沉积后形成污垢(Chalk Rivers Unidentified Deposits,CRUD)。硼酸作为控制反应性的添加剂,可能在过冷沸腾(Subcooled Nucleate Boiling,SNB)区域的污垢内析出,造成燃料组件轴向局部区域功率发生变化,增大反应堆发生垢致轴向功率偏移(Crud Induced Power Shift,CIPS)的风险。目前广泛采用硼析出量作为CIPS风险的判断依据,此方法可初步估计CIPS风险等级,但无法精确计算出燃料组件轴向功率偏移(Axial Offset,AO)程度。本文基于CRUD沉积和硼析出过程中的热工-化学机理,开发了模拟硼析出的分析模型,并结合物理计算程序对某压水堆的AO进行了计算。研究结果表明,热工-化学-物理耦合的分析方法能够识别出CIPS风险最大的燃料组件,并提供CRUD对该组件AO影响的量化计算结果,提升了预测压水堆CIPS风险的准确性。Corrosion products of metal materials in the primary circuit of PWR(Pressurized Water Reactor)flow through the core with coolant,and form CRUD(Chalk Rivers Unidentified Deposits)after deposition on the surface of fuel cladding.The boric acid,as an additive to control reactivity,may precipitate inside CRUD in SNB(Subcooled Nucleate Boiling)regions,which may cause the power change in the axial local area of fuel assembly and increase the risk of CIPS(Crud Induced Power Shift).At present,boron precipitation amount is widely used as the criteria for judging CIPS risk.This method can preliminarily estimate CIPS risk level,but unable to accurately calculate AO(Axial Offset)degree of the fuel assembly.Based on the thermodynamic-chemical mechanism of CRUD deposition and boron precipitation process,an analytical model for simulating boron precipitation is developed,and the AO of a PWR is calculated with a physical calculation program.The research results show that the thermal-chemical-physical coupling analysis methodology can identify the fuel assembly with the greatest CIPS risk,and provide quantitative results of the influence of CRUD on the AO of the fuel assembly,which improves the accuracy of predicting CIPS risk of PWR.

关 键 词：压水堆 污垢 过冷沸腾 硼析出 垢致轴向功率偏移 

分 类 号：TL383[核科学技术—核技术及应用]