Understanding and Pathways to Avoid Major Fuel Failures and Radionuclide Releases in Fluoride Salt–Cooled High-Temperature Reactor Severe Accidents
Understanding and Pathways to Avoid Major Fuel Failures and Radionuclide Releases in Fluoride Salt–Cooled High-Temperature Reactor Severe Accidents
复制标题
氟化盐冷却高温反应堆严重事故的认识和避免重大燃料故障和放射性核素释放的途径
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
R. Ballinger
中科院分区：
文献类型：
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作者：
C. Forsberg;J. Stempien;M. J. Minck;R. Ballinger
摘要氟化物盐冷高温堆是一种新型的动力堆，它在600°C ~ 700°C之间向动力循环输送热量。FHR使用高温气冷堆（HTGR）石墨基包覆颗粒燃料，失效温度约为1650°C。FHR冷却剂是熔点高于350°C、沸点高于1400°C的清洁氟化物盐。这种组合可以使大型FHR的设计不会有显著的燃料故障，因此即使在包括所有冷却系统、容器和安全壳系统故障的超设计基准事故（BDBA）中也不会有放射性核素释放到环境中。第一次努力已经进行，以了解FHR BDBA和开发FHR BDBA系统，以防止重大燃料故障，如果事故发生在一个大型FHR。四个设计特征将BDBA燃油温度限制在低于燃油故障温度。首先，在BDBA中，存在大的温度下降以将衰变热从燃料传递到环境。其次，正常运行温度和燃料故障温度之间的巨大温差允许在事故中使用升高的温度来降低绝缘系统和其他屏障，从而阻止事故中衰变热从反应堆堆芯有效传递到环境。第三，反应堆容器周围的筒仓含有一种BDBA盐，在事故中会加热、熔化并部分淹没筒仓，以改善从燃料到环境的热传递。第四，燃料和冷却剂在高温下保留裂变产物和锕系元素。
Abstract Fluoride salt–cooled High-temperature Reactors (FHRs) are a new type of power reactor that delivers heat to the power cycle between 600°C and 700°C. The FHR uses High-Temperature Gas-cooled Reactor (HTGR) graphite-matrix coated-particle fuel with failure temperatures of ~1650°C. The FHR coolants are clean fluoride salts that have melting points above 350°C and boiling points above 1400°C. This combination may enable the design of a large FHR that will not have significant fuel failure and thus radionuclide releases to the environment even in a beyond-design-basis accident (BDBA) that include failure of all cooling systems, the vessel, and containment systems. A first effort has been undertaken to understand FHR BDBAs and develop an FHR BDBA system to prevent major fuel failure if an accident occurs in a large FHR. Four design features limit BDBA fuel temperatures to lower than fuel failure temperatures. First, there is a large temperature drop to transfer decay heat from the fuel to the environment in a BDBA. Second, the large temperature difference between normal operating temperatures and fuel failure temperatures allows the use of increasing temperatures in an accident to degrade the insulation system and other barriers that prevent efficient transfer of decay heat from the reactor core to the environment in an accident. Third, the silo around the reactor vessel contains a BDBA salt that in an accident heats up, melts, and partly floods the silo to improve heat transfer from fuel to the environment. Fourth, the fuel and coolant retain fission products and actinides at high temperatures.