Abstract Passive autocatalytic recombiners (PARs) have become one of the primary measures to mitigate the hydrogen risk for severe accidents in current and advanced water-cooled nuclear power plants (NPPs). The pgm (platinum group metals) coating of the catalyst inside the PAR is capable to oxidize hydrogen into water vapor as well as to convert carbon monoxide into carbon dioxide. The optimal efficiency of conversion requires a significant surplus of oxygen compared to the stoichiometric oxidization. A test series under containment typical boundary conditions was performed in the THAI facility (Thermal-hydraulics, Hydrogen, Aerosols and Iodine) to investigate the PAR performance under the presence of carbon monoxide. Ratios of injection mass flow rates of hydrogen and carbon monoxide into the test facility are investigated between 4:1 and 7:1, based on hypothetical release of CO by the molten core concrete interaction (MCCI). The findings are related to database on PAR performance carried out in previous OECD/NEA projects, THAI (2007–2009), THAI-2 (2011–2014), and THAI-3 (2016–2019). Special emphasis is placed on the investigation of the PAR under conditions of oxygen starvation, taking also into account a potential PAR poisoning by carbon monoxide, and under potential PAR induced ignitions at elevated hydrogen and carbon monoxide concentrations.

中文翻译：

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在 THAI 设施的典型安全壳条件下，测量一氧化碳对被动自催化复合器性能的影响

摘要 被动自催化复合器（PARs）已成为减轻当前和先进水冷核电站（NPPs）严重事故氢气风险的主要措施之一。PAR 内催化剂的 pgm（铂族金属）涂层能够将氢气氧化成水蒸气，并将一氧化碳转化为二氧化碳。与化学计量氧化相比，最佳转化效率需要大量过剩的氧气。在 THAI 设施（热液压、氢气、气雾剂和碘）中，在安全壳典型边界条件下进行了一系列测试，以研究一氧化碳存在下的 PAR 性能。在 4:1 和 7:1 之间研究氢气和一氧化碳注入测试设施的质量流量比，基于熔融核心混凝土相互作用 (MCCI) 的假设释放 CO。调查结果与之前经合组织 / NEA 项目 THAI（2007-2009）、THAI-2（2011-2014）和 THAI-3（2016-2019）中执行的 PAR 性能数据库有关。特别强调在缺氧条件下对 PAR 的研究，还考虑到一氧化碳可能导致 PAR 中毒，以及在氢气和一氧化碳浓度升高时潜在的 PAR 诱发点火。