VESTA Test Facility for Severe Accident Researches at KAERI

摘要

VESTA (Verification of Ex-vessel corium STAbilization) test facility constructed at KAERI in 2010 is used to perform various corium melt experiments. Since 2010, several tests have been performed for the verification of an ex-vessel core catcher design for the EU-APR1400. Jet impingement tests were performed to investigate the ablation characteristics of the sacrificial material by ZrO_2 melt. ZrO_2 melt of 65 to 70kg was discharged on the sacrificial material through a well-designed nozzle and the ablation depths were measured. Interaction tests between metallic melt and sacrificial material were performed to investigate the interaction kinetics of the sacrificial material. Two types of melt were used; one is the metallic corium melt with Fe 46%, U 31%, Zr 16%, and Cr 7% and the other is stainless steel (SUS304) melt. Metallic melt of 1.5 to 2.0kg was delivered to the sacrificial material, and the ablation depths were measured. In addition, penetration tube failure tests were also performed for the APR1400 equipped with 61 in-core-instrumentation penetration nozzles and extended tubes at the reactor lower vessel. ZrO_2 melt was generated in a melting crucible and delivered down into an interaction crucible where the test specimen is installed. Sustained heat was supplied to the interaction crucible by an induction heater after the delivery of the melt from the melting crucible. Temperature distributions of the reactor bottom head and in-core-instrumentation penetration were measured by a series of thermocouples embedded along the specimen to evaluate the tube ejection mechanism. It is noted that the VESTA test facility has been used for various severe accident researches with corium and simulant melts at KAERI.