Article ID Journal Published Year Pages File Type
1728845 Annals of Nuclear Energy 2012 13 Pages PDF
Abstract

Some nuclear power plants in Korea were found to be leaking due to debris- and grid-to-rod fretting wear (GTRF)-induced fuel failures. Evaluation models for pellet-to-gap escape rates and gap-to-coolant release rates have been developed with the use of the primary coolant activity variations. It is found that the gap-to-coolant release rates for the debris fuel failure are different from those for the GTRF fuel failure. The gap-to-coolant release rate is controlled by both the primary defect and the secondary hydride-induced defect. The secondary hydride-induced through-cracks are more effective for the release of iodine and xenon than the primary defect. The fission product inventories in the gap and the gap-to-coolant release rates can be explained by the time-dependent defect progress, the water phase around the defects, the steam in the fuel gap, the pellet-to-clad contact, and the spacer grid springs/dimples contacting the defect.

► Coolant activities are found to be different for debris- and GTRF-induced fuel failure. ► Evaluation models for fission product inventory and escape and release rates are developed. ► Escape and release rates are generated using primary coolant activity variations. ► Release rates are dependent on primary defect and secondary defect progress with time. ► Secondary hydride-induced through crack is more effective than primary defect for debris.

Related Topics
Physical Sciences and Engineering Energy Energy Engineering and Power Technology
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