No abstract

The Fukushima nuclear disaster has raised the focus on the reliability and risk evaluation of the spent fuel pool (SFP), especially the fire risk. From a safety point of view, the low decay heat of the spent fuel assemblies and large water inventory may make the accident progress very slow, but a large number of fuel assemblies stored inside the pool and without containment above the SFP building might bring greater risk. For pressurized water reactor HPR1000 nuclear power plant, the reliability and risk of spent fuel pool under internal fire is assessed. The fire probabilistic safety analysis method is used to assess the reliability and risk of spent fuel pool under internal fire. Through quantitative analysis, we can know more about which aspects play a leading role in the internal fire risk contribution.

The Fukushima nuclear disaster has raised the importance on the reliability and risk research of the spent fuel pool (SFP), including the risk of internal events, fire, external hazards and so on. From a safety point of view, the low decay heat of the spent fuel assemblies and large water inventory in the SFP has made the accident progress goes very slow, but a large number of fuel assemblies are stored inside the spent fuel pool and without containment above the SFP building, it still has an unignored risk to the safety of the nuclear power plant. In this paper, a standardized approach for performing a holistic and comprehensive evaluation approach of the SFP risk based on the probabilistic safety analysis (PSA) method has been developed, including the Level 1 SFP PSA and Level 2 SFP PSA and external hazard PSA. The research scope of SFP PSA covers internal events, internal flooding, internal fires, external hazards and new risk source-fuel route risk is also included. The research will provide the risk insight of Spent Fuel Pool operation, and can help to make recommendation for the prevention and mitigation of SFP accidents which will be applicable for the SFP configuration risk management.

No abstract

Damage to fuel assemblies and the release of radioactive substance may occur during fuel lifting and storage in nuclear power plant. For the purpose of quantitatively evaluate internal events, internal and external hazards induced risk of spent fuel pool and related fuel lifting facilities, to identify weaknesses of the fuel route design and provide corresponding risk insights, the methodology of fuel route probabilistic safety assessment (PSA) is systematically summarized in this study, and based on the design characteristics of a specific pressurized water reactor nuclear power plant, fuel damage frequencies and radioactive substance release frequencies in the fuel route are assessed, some possible further safety improvements for the fuel route are identified. The results of analysis case show that the fuel building ventilation system failure has the largest contribution to the overall fuel thermal damage frequency, while the spent fuel crane failure has the largest contribution to the overall fuel mechanical damage frequency. The drop of the spent fuel cask full of spent fuels in loading pit has a prominent contribution to the risk of radioactive substances release due to the mechanical damage. The safety risk in the fuel route can be effectively reduced by the diversified design of local cooling unit fans in fuel building ventilation system and type modification of the spent fuel pool crane.