摘要
乏燃料水池中存放乏燃料组件,依靠池水带走衰变热、屏蔽放射性,失去冷却是乏燃料水池最严重的事故工况之一。在池水逐渐蒸干和快速流失两种失冷方式下,基于可能的事故过程,研究芯块和池水温度升高、棒栅距失控、组件严重损毁、中子吸收体失效等各种假设情景对临界安全的影响,并对各种假设情景的可信度进行了评估。研究结果表明:水的丧失使系统的慢化能力大幅减弱,燃料温度升高引起的多普勒负反馈效应,都增加了系统的次临界安全裕量。即使在水池补水、重新淹没乏燃料的过程中,在可信的堆积模型下,系统也能够保证次临界安全。在不可信的中子吸收体硼钢损坏的情景下,得到非常保守的系统keff以及相应的缓解措施,仅供参考。基于目前的知识和工程经验,乏燃料水池失冷事故,在可信事故工况下,是可以保证次临界安全的。
The spent fuel storage pool accommodates spent fuel assemblies,and the coolant（pool water）removes the decay heat and acts as the shield against the radioactivity,therefore coolant loss is one of the most severe accidents.For two kinds of coolant loss,evaporating slowly and draining off rapidly,the relevant criticality safety is studied.The considered scenarios include temperature rises of pellets and coolant,loss of rod pitch control,gross assembly failure,neutron absorber failure,etc.And the credibility judgment of each scenario is carried out.The results show that coolant loss considerably decreases the slowing-down power,and that rise of pellet temperature and the relevant negative Doppler effect,both increase the subcritical margin.Even at the reflooding scenario,under the credible pile up model,the subcriticality can be ensured.Under the scenario that borated stainless steel disappears which is not credible,keffand the relevant mitigating measures which are considerably conservative,are listed in the paper only for reference.Based on current knowledge and engineering experience,the coolant loss of the spent fuel storage pool,under the credible accidental scenarios,is subcritical.
出处
《核科学与工程》
CAS
CSCD
北大核心
2016年第5期709-714,共6页
Nuclear Science and Engineering
关键词
乏燃料水池
失去冷却
临界安全
堆积模型
可信度评估
Spent fuel storage pool
Coolant loss
Criticality safety
Pile up model
Credibility judgment
