TOPAZ-Ⅱ空间堆特殊临界安全分析  

Special Criticality Safety Analysis for TOPAZ-ⅡSpace Reactor

作　　者：肖启冬 杨历军[1] 张鹏展 刘凯凯 刘洋[1] 刘东海[1] 吕征[1] XIAO Qidong;YANG Lijun;ZHANG Pengzhan;LIU Kaikai;LIU Yang;LIU Donghai;LYU Zheng(Department of Reactor Engineering Technology,China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院反应堆工程技术研究所,北京102413

出　　处：《原子能科学技术》2024年第12期2563-2569,共7页Atomic Energy Science and Technology

摘　　要：特殊临界安全事故是空间堆的设计基准事故,掉落的临界安全问题是发射之前需要详细论证的重要安全问题。当前国内外针对空间堆特殊临界安全问题的分析仅简单计算k_(eff),没有提出有效的分析论证方法。参照国际上通用的反应堆外易裂变材料的核临界安全分析方法,基于在与原型堆具有高度相似性的临界装置上获取的特殊临界安全实验数据,提出了一种合理的空间堆特殊临界安全分析方法。基于与TOPAZ-Ⅱ空间堆具有高度相似性的Narciss-M装置上获取的特殊临界安全实验数据,使用该方法对TOPAZ-Ⅱ空间堆的特殊临界安全问题进行了分析,结果表明该堆不满足临界安全要求;提出了TOPAZ-Ⅱ空间堆设计改进措施,并论证其可行性。The special criticality safety accidents refer to the unexpected supercriticality incidents that may occur when a space reactor falls to the Earth’s surface after a spacecraft launch abort or re-entry into the atmosphere,with the reactor core being water flooding and immersed in water or sand.The special criticality safety accident is the design basis accident of the space reactors,and the criticality safety issue of the space reactors falling to Earth is an important safety issue that needs to be demonstrated in detail before launch.At present,the analysis of special criticality safety problems at China and abroad only simply calculate k_(eff),and no effective analysis and demonstration methods has been proposed.With reference to the international nuclear criticality safety analysis method for fissionable materials outside reactors,a reasonable special criticality safety analysis method for space reactors is proposed on the basis of special criticality safety experimental datum obtained on a criticality assembly that has a high degree of similarity to the prototype reactors.This method calculated the k_(eff) of the space reactors under accident scenarios and superimposes the biasβand bias uncertaintyΔβderived from special criticality safety experimental datum.Based on the results of special criticality safety experiments conducted on the Narciss-M criticality assembly,combined with the possibilities of actual occurrences,it has been determined that the worst accident scenario faced by the TOPAZ-Ⅱspace reactor after falling on Earth is:The reactor core being water flooding,immersed in wet sand,and side reflector with control drum is off;The biasβ=0.00003 and bias uncertaintyΔβ=0.0041 also obtained.According to the special criticality safety analysis method proposed for space reactors,and the cold built-in reactivity of the TOPAZ-Ⅱspace reactor is 0.005Δk/k(i.e.,k_(eff)=1.005),the ks of the TOPAZ-Ⅱspace reactor in the worst accident scenario is calculated to be 1.02910±0.00008.After considering the

关 键 词：TOPAZ-Ⅱ空间堆 特殊临界安全 堆芯进水 水淹没 湿沙掩埋 

分 类 号：TL32[核科学技术—核技术及应用]