Understanding of the operation behaviour of a Passive Autocatalytic Recombiner (PAR) for hydrogen mitigation in realistic containment conditions during a severe Light Water nuclear Reactor (LWR) accident

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• 作者：Fré ; dé ; ric Payot^a ; ^{frederic.payot@irsn.fr} ; Ernst-Arndt Reinecke^b ; ^{e.-a.reinecke@fz-juelich.de} ; Franck Morfin^c ; ^{franck.morfin@ircelyon.univ-lyon1.fr} ; Jean-Christophe Sabroux^d ; ^{jean-christophe.sabroux@irsn.fr} ; Nicolas Meynet^e ; ^{nicolas.meynet@irsn.fr} ; Ahmed Bentaib^e ; ^{ahmed.bentaib@irsn.fr} ; Philippe March^a ; ^{philippe.march@irsn.fr} ; Roland Zeyen^f ; ^{roland.zeyen@irsn.fr}
• 刊名：Nuclear Engineering and Design
• 出版年：2012
• 期刊代码：132_00295493
• 类别：et
• 出版时间：July, 2012
• 卷：248
• 期：Complete
• 页码：178-196
• 文件大小：3071 K

摘要

In the context of hydrogen risk mitigation in nuclear power plants (NPPs), experimental studies of a possible poisoning of Passive Autocatalytic Recombiners (PARs) by fission products (FPs) and aerosols released during a core meltdown accident were mainly conducted in the past with non-radioactive fission product surrogates (e.g., in the H2PAR facility at Cadarache, France). The decision was taken in 1997 to complete these studies by a test in the Ph茅bus facility, a research nuclear reactor also at Cadarache: it was a rare opportunity to expose catalyst samples to an atmosphere as representative as possible of a core meltdown accident, containing gaseous fission products and aerosols released during the degradation of an actual irradiated nuclear fuel bundle. Before testing in Ph茅bus during the FPT3 experiment, reference and qualification tests were performed in the H2PAR facility using the same samples 鈥?the so-called 鈥渃oupons鈥?鈥?and coupons holder to check that the apparatus was functional and correctly designed for avoiding to tamper with the thermal-hydraulics and chemical conditions in the Ph茅bus containment. The correct operation of catalysts was checked by measuring the surface temperature increase of the coupons due to the exothermic reaction between hydrogen and oxygen. After the Ph茅bus FPT3 test (November 2004), REKO-1 tests were initiated at J眉lich, Germany, to confirm the discrepancy in coupons temperature observed in Ph茅bus FPT3 and H2PAR PHEB-03 tests, and to study the operation behaviour of PARs. Besides, before REKO-1 tests, a first interpretation of H2PAR and Ph茅bus experiments was led to the conclusion that their difference during the operation was due to the different experimental conditions. Samples of catalysts (IRSN/IRCELYON coupon) similar to those used in Ph茅bus and H2PAR facilities were exposed in REKO-1 facility to an atmosphere similar to that of the Ph茅bus model containment. During the REKO-1 experiments, the temperatures of the coupon surface, together with the oxygen and hydrogen recombination kinetics, were measured as a function of the oxygen fraction in the feed. In these conditions, the inlet oxygen fraction was shown to be the main parameter affecting the recombination rate. The presence of steam was also taken into account during the IRSN/IRCELYON coupon operation in REKO-1. Finally, the PAR surface temperatures during the REKO-1 tests (both optical and thermocouple measurements) are compared with those obtained during the FPT3 and PHEB-03 tests. Then, the experimental observations (from the Ph茅bus FPT3, H2PAR PHEB03 and REKO-1 tests) were corroborated by numerical calculations using the SPARK code developed at IRSN for catalytic reactors and recombiners applications. Despite the loss of performance experienced by the coupons in the FPT3 test, as compared with the PHEB-03 test, this study does not challenge the qualification of PARs for risk mitigation in Pressurized Water Reactor (PWR) NPPs, and suggests that they could still be efficient in the rich burn conditions of partially inerted (oxygen depleted) Boiling Water Reactor (BWR) containments.