FINAL REPORT on Experimental Validation of Stratified Flow Phenomena, Graphite Oxidation, and Mitigation Strategies of Air Ingress Accidents

Chang H. Oh ; Eung S. Kim ; Hee C. NO ; Nam Z. Cho

关键词: ACCIDENTS;    AIR;    DEPRESSURIZATION;    FRACTURES;    GRAPHITE;    IMPLEMENTATION;    LOSS OF COOLANT;    MITIGATION;    OXIDATION;    REACTOR PHYSICS;    SAFETY MARGINS;    THERMAL HYDRAULICS;    VALIDATION;    VERIFICATION Air Ingress accidents;    INERI;    NGNP;   

DOI  :  10.2172/1023463
RP-ID  :  INL/EXT-10-20759
PID  :  OSTI ID: 1023463
Others  :  TRN: US1104581

学科分类：核能源与工程

美国|英语

来源: SciTech Connect

【 摘 要 】

The U.S. Department of Energy is performing research and development that focuses on key phenomena that are important during challenging scenarios that may occur in the Next Generation Nuclear Plant (NGNP)/Generation IV very high temperature reactor (VHTR). Phenomena Identification and Ranking studies to date have identified the air ingress event, following on the heels of a VHTR depressurization, as very important. Consequently, the development of advanced air ingress-related models and verification & validation are of very high priority for the NGNP Project. Following a loss of coolant and system depressurization incident, air ingress will occur through the break, leading to oxidation of the in-core graphite structure and fuel. This study indicates that depending on the location and the size of the pipe break, the air ingress phenomena are different. In an effort to estimate the proper safety margin, experimental data and tools, including accurate multidimensional thermal-hydraulic and reactor physics models, a burn-off model, and a fracture model are required. It will also require effective strategies to mitigate the effects of oxidation, eventually. This 3-year project (FY 2008???FY 2010) is focused on various issues related to the VHTR air-ingress accident, including (a) analytical and experimental study of air ingress caused by density-driven, stratified, countercurrent flow, (b) advanced graphite oxidation experiments, (c) experimental study of burn-off in the core bottom structures, (d) structural tests of the oxidized core bottom structures, (e) implementation of advanced models developed during the previous tasks into the GAMMA code, (f) full air ingress and oxidation mitigation analyses, (g) development of core neutronic models, (h) coupling of the core neutronic and thermal hydraulic models, and (i) verification and validation of the coupled models.