Analysis of hydrogen and dust explosion after vacuum vessel rupture: Preliminary safety analysis of Korean fusion demonstration reactor using MELCOR
Analysis of hydrogen and dust explosion after vacuum vessel rupture: Preliminary safety analysis of Korean fusion demonstration reactor using MELCOR
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DOI：
10.1002/er.3793
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发表时间：
2018-01
影响因子：
4.6
通讯作者：
S. Moon;S. Lim;I. Bang
中科院分区：
文献类型：
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作者：
S. Moon;S. Lim;I. Bang
氢爆炸是核聚变和裂变反应堆中最危险的事故现象之一。在典型的聚变反应堆中，氚和氘是用于聚变反应的燃料元素，并且它们在正常操作条件下以冷凝状态存在于低温泵周围。在事故情况下，提高传热系统的温度会使真空容器中大量的氚发生迁移。然后，冷却剂可以与真空容器内产生氢气的高温结构反应。此外，空气进入等离子体终止了在第一壁面向等离子体的表面上产生活化粉尘的聚变反应。通过这一系列过程，活化的氚和尘埃气溶胶可以在真空容器中爆炸，破坏安全壳建筑物的完整性，使其成为一种源项，通过各种系统体积泄漏到环境中。本文对韩国聚变示范堆设想设计的氢气和粉尘爆炸事故进行了初步的安全分析。采用MELCOR系统分析程序对事故进行了模拟和参数分析，以研究对事故规模和安全系统（如加热、通风和空调隔离系统和压力抑制系统）的影响。估算了各控制体积气溶胶的分布及其释放途径，并将最终释放到环境中的气溶胶与ITER的释放准则进行了比较。利用ITER正常运行工况对示范堆气溶胶的可动量进行了保守估算。
Hydrogen explosion is one of the most dangerous accident phenomena in both nuclear fusion and fission reactor. In the typical fusion reactor, tritium and deuterium are fuel elements for fusion reaction, and they exist in condensed state around the cryo‐pump in the normal operation condition. In the accident situation, increasing heat transfer system temperature can mobilize lots of tritium in the vacuum vessel. And then, coolant can react with high‐temperature structures generating hydrogen gas inside vacuum vessel. In addition, air ingress into plasma terminates fusion reaction producing activated dust on the first wall plasma facing surfaces. Through these series of process, mobilized tritium and dust aerosol can explode in the vacuum vessel and damage the containment building integrity, making a sort of source term leakage to environment through various system volumes. In this paper, preliminary safety analysis for hydrogen and dust explosion accident for assumed design of Korean fusion demonstration reactor is conducted. An MELCOR system analysis code is used to simulate this accident and parametric analysis to investigate effect on the accident scale and safety systems like detritiation system such as heating, ventilation, and air conditioning isolation system and pressure suppression system. As a result, aerosol distribution of each control volume and its release route are estimated, and final aerosol release to the environment is compared with release guideline for ITER. The amount of mobilized aerosol in demonstration reactor is evaluated conservatively using ITER normal operation condition.