Safety implications of multiple passive safety valve failures in an i-SMR design

IF 3.2 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Progress in Nuclear Energy Pub Date : 2025-09-29 DOI:10.1016/j.pnucene.2025.106065

Chang Hyun Song , Sung Joong Kim

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引用次数: 0

Abstract

Small Modular Reactors (SMRs) are being developed as next-generation nuclear options in response to increasing global power demand driven by data centers, artificial intelligence, and industrial electrification. Korea's innovative SMR (i-SMR) is designed as an integral pressurized water reactor with a thermal output of 520 MWth, aiming to achieve a core damage frequency below 1.0E-09 per year. To meet these goals, the i-SMR adopts multiple Passive Safety Systems (PSSs), including the Passive Emergency Core Cooling System (PECCS), which ensures core cooling through depressurization and natural recirculation. While previous studies have validated the effectiveness of PSSs under nominal conditions, their performance under multiple passive valve failures remains underexplored. In particular, the emergency depressurization valves, and emergency recirculation valves are critical components that enable passive cooling. If one or more of these valves fail to function as designed, coolant may be lost rapidly or recirculation hindered, accelerating fuel exposure. In this study, a detailed MELCOR input model of the i-SMR was developed to analyze accident progression behavior under multiple passive valve failures, particularly focusing on PECCS-related valves. MELCOR simulation results revealed that partial valve failures can lead to faster core degradation than complete system failure scenarios. These findings highlight the critical need to incorporate design redundancy and diversity in passive valve components to ensure reliable accident mitigation capabilities in the i-SMR.

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i-SMR设计中多个被动安全阀失效的安全含义

为了应对数据中心、人工智能和工业电气化推动的全球电力需求不断增长，小型模块化反应堆（smr）正在被开发为下一代核选择。韩国的创新SMR （i-SMR）被设计为一个整体压水反应堆，热输出为520兆瓦，目标是将堆芯损坏频率降低到每年1.0E-09以下。为了实现这些目标，i-SMR采用了多个被动安全系统（pss），包括被动应急堆芯冷却系统（PECCS），该系统通过降压和自然再循环确保堆芯冷却。虽然之前的研究已经验证了pss在名义条件下的有效性，但它们在多次被动阀门故障下的性能仍未得到充分研究。特别是，紧急降压阀和紧急再循环阀是实现被动冷却的关键部件。如果这些阀门中的一个或多个不能按设计工作，冷却剂可能会迅速流失或再循环受阻，加速燃料暴露。在本研究中，开发了i-SMR的详细MELCOR输入模型，以分析多个被动阀门故障下的事故进展行为，特别是与peccs相关的阀门。MELCOR的模拟结果显示，与整个系统故障相比，部分阀门故障会导致更快的岩心退化。这些发现强调了在被动阀组件中整合设计冗余和多样性的关键需求，以确保i-SMR可靠的事故缓解能力。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Progress in Nuclear Energy 工程技术-核科学技术

CiteScore

5.30

自引率

14.80%

发文量

331

审稿时长

3.5 months

期刊介绍： Progress in Nuclear Energy is an international review journal covering all aspects of nuclear science and engineering. In keeping with the maturity of nuclear power, articles on safety, siting and environmental problems are encouraged, as are those associated with economics and fuel management. However, basic physics and engineering will remain an important aspect of the editorial policy. Articles published are either of a review nature or present new material in more depth. They are aimed at researchers and technically-oriented managers working in the nuclear energy field. Please note the following: 1) PNE seeks high quality research papers which are medium to long in length. Short research papers should be submitted to the journal Annals in Nuclear Energy. 2) PNE reserves the right to reject papers which are based solely on routine application of computer codes used to produce reactor designs or explain existing reactor phenomena. Such papers, although worthy, are best left as laboratory reports whereas Progress in Nuclear Energy seeks papers of originality, which are archival in nature, in the fields of mathematical and experimental nuclear technology, including fission, fusion (blanket physics, radiation damage), safety, materials aspects, economics, etc. 3) Review papers, which may occasionally be invited, are particularly sought by the journal in these fields.