Improvement of fuel-coolant interaction models for ex-vessel debris coolability evaluation

松本 俊慶; 川部 隆平; 杉山 智之; 丸山 結

no journal, , 

In severe accident at nuclear power stations, molten core materials can fall into the cavity/pedestal space of containment vessel (CV) after lower head failure. Molten core materials can erode the base mat concrete and generate combustible gases. The core coolability is a key issue for the integrity of CVs. Water injection into the CV is one of the accident management measures to mitigate the molten core concrete interaction (MCCI). Model improvements for the JASMINE code were conducted to improve the capability of the assessment of MCCI. The Rosin-Rammler distribution was implemented as the jet breakup particle diameter distribution. A crust formation model was also implemented to simulate molten core solidification in spreading on the floor. The improved models were applied to the analyses of the DEFOR-A and PULiMS tests conducted by the Royal Institute of Technology (KTH, Sweden) to investigate the jet breakup and melt spreading on the floor in water pool using core simulant materials.