A STUDY ON IN-VESSEL SEVERE ACCIDENT PROGRESSION IN THE VVER-1000 REACTOR PRESSURE VESSEL
Main Article Content
Abstract
The present paper is concerned with the hypothetic in-vessel accident progression in the VVER-1000 Reactor Pressure Vessel (RPV). During the accident progression, there is likelihood that the core is degraded, melted down, core materials are relocated, and a melt pool is formed in the lower plenum of RPV. Without adequate cooling, the relocated corium is heated up, melted and attacks the vessel wall, causes its failure. Different Severe Accident Management (SAM) measures may be applicable for mitigation of accident consequences. In this study, the Station Blackout (SBO) accident is considered, in-vessel accident progression is analyzed. Simulation of melt pool heat transfer in the VVER-1000 lower head is performed for selected scenarios, the efficiency of potential SAM measures is evaluated. The Phase-change Effective Convectivity Model (PECM) which has been recently developed for melt pool formation heat transfer simulation is employed. It is shown that water injection into the reactor does not significantly delay the vessel failure, combination of water injection and reactor vessel external cooling operated several hours after the accident start may avoid the vessel failure.
Article Details
Keywords
accident progression, core materials, natural convection, heat transfer, effective convectivity model, vessel ablation, vessel failure, water injection, external cooling
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