CNSC Expectations for Resolution of the Hydrogen Safety Issues

Abstract

The TMI and Chernobyl severe accidents of 1979 and 1986 demonstrated the containment crucial role in preventing radioactive releases and highlighted the hydrogen combustion safety challenges.The CNSC issued the containment regulatory document R-7 and initiated Generic Action Item GAI 88G02 to resolve the hydrogen challenges, following the R-7 approach.In the early 2000-s, the IAEA issued in response its NS-R-1 NPP design standard. Many countries followed suit. They established rules to protect the containment and installed passive autocatalytic recombiners (PAR) to reduce the hydrogen risk.In 2002, the CNSC started updating its documents based on the IAEA standards. Because the R-7 design basis rules could not be fully met by current NPP, the CNSC decided to use the new RD-337 NPP design document to address the hydrogen risk.In this paper, we describe the current CNSC expectations for reducing the hydrogen risk in new, operating and refurbished NPP over the full spectrum of accidents including severe accidents for adequate containment protection.