Abstract During a severe accident in a nuclear reactor, there are a number of phenomenological events that can present a challenge to containment integrity. These include the generation and combustion of hydrogen, energetic fuel-coolant interactions, thermal attack of fission product barriers, core-concrete interactions, direct containment heating, and gradual overpressurization. The advanced design of the NuScale small modular reactor (SMR) has resulted in the reduced likelihood and severity of severe accident challenges to containment. This paper discusses the features of the NuScale design that reduce the likelihood of occurrence of these severe accident phenomena and also discusses the ability of containment to survive in the unlikely event that they do occur. The impact of severe accident phenomena for the NuScale design is compared and contrasted against other advanced light water reactors (ALWRs), such as the AP1000 reactor and the Economic Simplified Boiling Water Reactor (ESBWR), as well as the existing fleet, using information from publicly available documents.

中文翻译：

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严重事故现象：NuScale SMR、其他先进 LWR 设计和运行 LWR 之间的比较

摘要 在核反应堆发生严重事故期间，会发生许多现象学事件，对安全壳完整性提出挑战。这些包括氢气的产生和燃烧、高能燃料-冷却剂相互作用、裂变产物屏障的热攻击、核心-混凝土相互作用、直接安全壳加热和逐渐超压。NuScale 小型模块化反应堆 (SMR) 的先进设计降低了安全壳严重事故挑战的可能性和严重性。本文讨论了 NuScale 设计的特点，这些特点降低了这些严重事故现象发生的可能性，还讨论了安全壳在它们确实发生的可能性不大的情况下生存的能力。