Probabilistic Risk Assessment of Bolted Dry Spent Fuel Storage Cask

2004 ◽  
Author(s):  
Jeffrey T. Mitman ◽  
Ken Canavan
Keyword(s):  
Risk Assessment ◽  
Life Cycle ◽  
Probabilistic Risk Assessment ◽  
First Year ◽  
Pressurized Water Reactor ◽  
Spent Fuel ◽  
Pressurized Water ◽  
Spent Fuel Storage ◽  
Fuel Storage ◽  
Probabilistic Risk

EPRI performed a Probabilistic Risk Assessment (PRA) of a dry spent fuel storage cask. The study was performed for a bolted cask at a “generic” pressurized water reactor site. A generic site was chosen so the widest variety of challenges could be considered. The study calculates the annual individual radiological risk and consequences associated with a single cask life cycle, where the life cycle is divided into three phases: loading, on-site transfer, and on-site storage. The project used standard methods of PRA with the following analysis tasks: initiating event (IE), data, human reliability, structural, thermal hydraulic, accident sequence, and consequence. The results shows that the risk is extremely low with no calculated early fatalities and a first year risk of latent cancer fatality of 3.5E−11 per year per cask. Subsequent year risk to the general public is even lower; with, again, no early fatalities and a cancer risk of 4.2E−12.

Development of a Thermal Analysis Model for a Nuclear Spent Fuel Storage Cask and Experimental Verification With Prototype Testing

1989 ◽  
Vol 111 (4) ◽  
pp. 647-651 ◽  
Author(s):  
J. Y. Hwang ◽  
L. E. Efferding
Keyword(s):  
Thermal Analysis ◽  
Storage Period ◽  
Department Of Energy ◽  
Pressurized Water Reactor ◽  
Spent Fuel ◽  
Analysis Model ◽  
Pressurized Water ◽  
Fuel Assemblies ◽  
Spent Fuel Storage ◽  
Fuel Storage

A thermal analysis evaluation is presented of a nuclear spent fuel dry storage cask designed by the Westinghouse Nuclear Components Division. The cask is designed to provide passive cooling of 24 Pressurized Water Reactor (PWR) spent fuel assemblies for a storage period of at least 20 years at a nuclear utility site (Independent Spent Fuel Storage Installation). A comparison is presented between analytical predictions and experimental results for a demonstration cask built by Westinghouse and tested under a joint program with the Department of Energy and Virginia Power Company. Demonstration testing with nuclear spent fuel assemblies was performed on a cask configuration designed to store 24 intact spent fuel assemblies or canisters containing fuel consolidated from 48 assemblies.

Recommendations for Conducting Probabilistic Risk Assessment of Spent Fuel Storage Facilities

2017 ◽  
Author(s):  
Sai Zhang ◽  
Jun Zhao ◽  
Jiejuan Tong ◽  
Zhixin Xu
Keyword(s):  
Nuclear Power ◽  
Reactor Core ◽  
Spent Fuel ◽  
Complementary Method ◽  
Fuel Assemblies ◽  
Spent Fuel Storage ◽  
Fuel Storage ◽  
Storage Units ◽  
Storage Facilities ◽  
Probabilistic Risk

Currently, the probabilistic risk assessments (PRA) for the nuclear power plant (NPP) sites are primarily focused on the reactor counterpart. However, evoked by the 2011 Fukushima Daiichi accident, it has been widely recognized that a complete site risk profile should not be confined to the reactor units, but should cover all the radiological sources in a site, e.g. spent fuel storage facilities. During the operation of the reactor units, the used fuel assemblies will be unloaded from the reactor core to the storage facilities in a continuous or periodical manner. Accident scenarios involving such facilities can occur with non-negligible frequencies and significant consequences, posing threat to public safety. Hence, the risk contributions from such scenarios should be carefully estimated and integrated into the safety goal evaluations. The spent fuel storage facilities can be categorized as two types: pool storage units and dry cask storage facilities. In the former type, spent fuel assemblies are stored in large pools inside or outside the reactor building, with the residual heat removed by natural or forced water circulation. The latter type, where air or inert gas circulation plays an important role, appear mostly as a complementary method, along with the pool storage units, to expand the plant’s storage capacity. For instance, at the Daiichi plant, there are several fuel pool units holding some fresh fuel and some used fuel, the latter awaiting for its transfer to the dry cask storage facilities on site. Note that, as well as in a joint manner, both storage facilities can be designed to serve the NPPs independently. As a fully developed method to identify potential risk in a logical and quantitative way, the framework of PRA can be generally applied to the spent fuel storage facilities with some special considerations. This paper is aimed at giving recommendations for the spent fuel storage facility PRAs, including (1) clarifying the analysis scope of risk from spent fuel storage facilities; (2) illustrating four key issues that determines such risk; (3) presenting three essential considerations when conducting PRAs to evaluate such risk. Also, this paper integrates the insights obtained from two representative case studies involving two NPP sites with different types of both fuel elements and storage facilities.

Safety Enhancement Study of CAP1400 Spent Fuel Storage Racks

2017 ◽  
Author(s):  
Xiaoming He ◽  
Ziqiang Zhu ◽  
Changlei Shao ◽  
Ran Huang
Keyword(s):  
Structural Safety ◽  
Spent Fuel ◽  
Pressurized Water ◽  
Neutron Absorber ◽  
Spent Fuel Storage ◽  
Fuel Storage ◽  
Criticality Analysis ◽  
Storage Racks ◽  
Safety Enhancement ◽  
Criticality Safety

Safety enhancement is essential to spent fuel storage racks of nuclear power plant after Fukushima accident. Criticality safety, cooling safety and structural safety enhancement for CAP1400 (a larger advanced pressurized water reactor developed by China) spent fuel storage racks of are proposed and prominent results have been obtained. The criticality analysis results indicate that neutron absorber insert is efficient to increase criticality safety of storage rack. The CFD simulation and seismic analysis reveal that these storage racks can meet the cooling safety and structural integrity requirements. Both neutron absorber inserts and passive spent fuel pool cooling technology have good application prospect.

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