新型吸收剂与局部慢化剂相结合的快堆控制棒设计研究  

Innovative Control Rods for Fast Reactors with New Absorbers and Local Moderators

作　　者：郭辉 顾汉洋[1] 冯快源 于超 GUO Hui;GU Hanyang;FENG Kuaiyuan;YU Chao(School of Nuclear Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;China Nuclear Power Research Institute,Shenzhen of Guangdong Prov.518026,China)

机构地区：[1]上海交通大学核科学与工程学院,上海200240 [2]中广核研究院有限公司,广东深圳518026

出　　处：《核科学与工程》2022年第1期44-52,共9页Nuclear Science and Engineering

基　　金：上海市扬帆计划(20YF1420700),上海交通大学优秀青年教师启动项目。

摘　　要：新一代快堆对其控制棒的安全性、使用寿命和经济性提出了更高的要求。传统快堆控制棒以碳化硼(B_(4)C)为吸收剂,但B_(4)C的气体释放、吸收力损失、高温包壳碳化失效及辐照膨胀限制了其安全使用寿命。本文利用能有效处理控制棒空间自屏蔽现象的确定论计算方法,设计并分析了基于替代吸收剂与局部慢化剂的快堆新型控制棒。本文从中子吸收能力、安全特性及废物处理等方面考察了硼化物、氢化物、稀土金属氧化物及金属四大类多种吸收剂。结果表明在不同吸收力区间,都有相应新型吸收剂可替代传统B_(4)C。大型快堆控制棒所需吸收力较低,可利用稀土金属氧化物作为长寿期吸收材料;中型快堆可考虑使用导热性优异的TiB_(2)或中子特性良好的HfH_(1.62);小型模块化快堆可考虑使用HfB_(2)作为超长寿期吸收剂。本文还介绍了吸收剂与慢化剂相结合的新型控制棒,结果表明局部慢化剂可加强控制棒吸收能力或节约吸收剂使用。本文结果将为快堆新型控制棒的研发提供重要参考。The control rod in sodium fast reactors is a cluster of open pins with boron carbide(B_(4)C)as the absorber.The enrichment of 10B can be adjusted to satisfy different requirements on the reactivity control.However,irradiation effects such as gas release,heat production,and pellet swelling limit the safety performance and service time of conventional control rods.The spatial self-shielding effect and its variation is the decisive factor in the modeling of control rods in fast reactors.This paper uses an improved deterministic calculation scheme to improve and assess control rod designs in next-generation fast reactors.Various alternative absorbers are assessed according to their neutronic performance,safety performance,and waste management.The results show that there are alternative choices to conventional absorber at different absorption levels.The large fast reactors,such as commercial reactors,usually exhibit reduced reactivity loss and require long operating life of control rods.In this case,Eu_(2)O_(3) would be very suitable thanks to their small worth loss under irradiation.In medium-size fast reactors,TiB_(2) can be considered for its high thermal conductivity.HfH_(1.62) proves excellent neutronic performance,while its hydrogen desorption issues should be further verified.In small modular fast reactors,HfB_(2) can be used with an extra-long operating lifetime because of its high melting point and limited swelling under irradiation.The combination of absorbers and moderators is also considered in this work.The use of moderators may save investment by reducing the use of absorber and increase the reactivity worth of the control rod.The moderator is able to homogenize the capture reaction spatial distribution and hence reduces the absorption peak.

关 键 词：快堆 控制棒 吸收剂 慢化剂 

分 类 号：TL371[核科学技术—核技术及应用]