134Cs与137Cs放射性活度比在破损燃料组件定位的应用研究

Theoretical research on location of fuel assemblies failure using the activity ratio of 134Cs and 137Cs

对破损燃料组件快速准确的定位,不仅可以为堆芯紧急换料提供宝贵时间,同时也缩短了大修的关键路径。本文对燃料组件中^134Cs与^137Cs放射性活度比与燃耗的关系进行了研究,并通过ORIGEN软件对计算得到的理论模型进行修正。研究发现:^134Cs与^137Cs放射性活度比随燃耗的增加而增大,随燃料组件富集度的增大而减小;通过修正后的^134Cs/^137Cs活度比与燃耗的关系可以确定压水堆核电厂不同燃料富集度下破损燃料组件的燃耗,进而实现对破损燃料组件准确的定位。

[Background]It is very important to locate ruptured fuel assemblies rapidly and accurately not only for emergency core refueling,but also for shortening critical path of overhaul.[Purpose]This study aims at location of fuel assemblies failure using the activity ratio of ^134Cs and ^137Cs.[Methods]The relationship between the ratio of ^134Cs to ^137Cs activity and fuel consumption in the fuel assembly was theoretically calculated,and the theoretical model was modified by ORIGEN software.[Results&Conclusions]It is found that the activity ratio of ^134Cs to ^137Cs increases with the increase of the burn-up,and decreases with the increase of fuel assembly enrichment.With the improved ^134Cs to ^137Cs activity ratio and burnup model,the burnup of damaged fuel assemblies at different enrichment levels in pressurized water reactor(PWR)nuclear power plants can be determined,and then the damaged fuel assemblies can be quickly located.