上钠腔设计对大型MOX燃料快堆冷却剂沸腾瞬态的影响研究  

Study on Influence of Upper Sodium Plenum Design on Coolant Boiling Transient in Large MOX Fuel Fast Reactor

作　　者：张熙司[1] 李新宇 霍兴凯 徐李[1] 刘一哲[1] 薛方元 ZHANG Xisi;LI Xinyu;HUO Xingkai;XU Li;LIU Yizhe;XUE Fangyuan(China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《原子能科学技术》2024年第9期1866-1875,共10页Atomic Energy Science and Technology

基　　金：中国原子能科学研究院“青年英才”培养基金(YC232505001406)。

摘　　要：钠空泡反应性效应是钠冷快堆核设计和安全分析的重要内容。本文基于多群节块扩散法,采用微扰理论对1000 MWe钠冷快堆具有上钠腔结构的MOX燃料堆芯的总钠空泡反应性、空间分布、物理分项进行计算。基于钠空泡反应性的计算结果,利用中国原子能科学研究院自主开发的钠冷快堆堆芯瞬态分析程序对1000 MWe钠冷快堆进行了无保护失流事故的瞬态分析,分别对具有上钠腔设计的堆芯和无上钠腔结构的堆芯安全性进行了评价。分析结果表明,上钠腔设计大大缓解了钠冷快堆冷却剂沸腾瞬态的事故后果,为钠冷快堆堆芯的安全设计提供了重要参考。Unprotected loss of flow accident is severe for sodium-cooled fast reactor in that it will cause the boiling of sodium and then cause severe accident.For large MOX fuel sodium-cooled fast reactors,the sodium void reactivity is positive,which can make the consequences of unprotected loss of flow accidents more severe.The design of the upper sodium plenum is an effective method for reducing sodium void reactivity in MOX fuel.The purpose of this paper is to evaluate the effect of upper sodium plenum design on the unprotected loss of flow accident in the large MOX fuel 1000 MWe sodiumcooled fast reactor.Based on multi-group nodule diffusion method and perturbation theory,the total sodium void reactivity,spatial distribution and physical components of MOX fuel core with upper sodium plenum in 1000 MWe sodium-cooled fast reactor were calculated.Based on the results of the calculation of sodium void reactivity,the transient analysis of the 1000 MWe sodium-cooled fast reactor core was carried out by using the transient analysis code CODA developed by China Institute of Atomic Energy.The assessment of the CODA code was carried out,by using the code to model experiments that simulate a loss of flow accident in a sodium-cooled fast reactor.Comparison of the predictions with experiment,confirm the ability of the CODA code to predict the principal sodium boiling phenomena.In order to better evaluate the reactivity effects,especially the sodium void reactivity,the CODA code adopted a model that considered the spatial distribution of reactivity feedback.The unprotected loss of flow transients with and without sodium plenum were evaluated respectively by CODA code.For the traditional core without upper sodium plenum,sodium void reactivity is strongly positive.In the case of an unprotected loss of flow accident,rapid generation of sodium vapor in the central part of the core leads to introduction of positive reactivity,rapid increase of power,and finally leads to fuel melting and relocation.For sodium-cooled fast reactor designs

关 键 词：钠冷快堆 钠空泡反应性 微扰理论 MOX燃料 无保护失流事故 冷却剂沸腾 

分 类 号：TL364.4[核科学技术—核技术及应用]