The accident was caused by the Great East Japan earthquake and Tsunami at TEPCO's Fukushima Daiichi Nuclear power plants. In order to evaluate the plant status after the accident of Fukushima Daiichi Nuclear Power Plants, the simulation has been investigated by the SAMPSON severe accident code. In this paper, the status of Fukushima Daiichi Nuclear Power Plant unit 1 analyzed by the SAMPSON code is shown. At unit 1, water injection by isolation condenser was terminated at 0.8 hour after scram. After termination, water level inside reactor pressure vessel was decreased by evaporation of water because of the decay heat of fuel rod and etc. The gradual decrease in pressure of reactor pressure vessel by the beak of pipe for source range monitor and the leak of the gasket of safety relief valve was assumed in this simulation. After melting core structure, because the model of the behavior of debris has been improved, a status of the debris was influenced. The debris was retained on the core plate until melting core plate as conventional model, but the model was improved based on results of XR2-1 experiment so that the debris felled to lower plenum by considering a other process of the fall of the debris. After falling debris, by the model of reactor pressure vessel failure improved, the behavior of debris falling from reactor pressure vessel was influenced. The improved model was considered not only the failure of reactor pressure wall but melting of instrument pipe penetrated to the inside of reactor pressure vessel. Applying these improved models, the results of the simulation after operating sea water injection was shown.
Accident analysis of Fukushima Daiichi nuclear power plant unit 1 by the sampson severeaccidentcode
Pellegrini M.;
2015-01-01
Abstract
The accident was caused by the Great East Japan earthquake and Tsunami at TEPCO's Fukushima Daiichi Nuclear power plants. In order to evaluate the plant status after the accident of Fukushima Daiichi Nuclear Power Plants, the simulation has been investigated by the SAMPSON severe accident code. In this paper, the status of Fukushima Daiichi Nuclear Power Plant unit 1 analyzed by the SAMPSON code is shown. At unit 1, water injection by isolation condenser was terminated at 0.8 hour after scram. After termination, water level inside reactor pressure vessel was decreased by evaporation of water because of the decay heat of fuel rod and etc. The gradual decrease in pressure of reactor pressure vessel by the beak of pipe for source range monitor and the leak of the gasket of safety relief valve was assumed in this simulation. After melting core structure, because the model of the behavior of debris has been improved, a status of the debris was influenced. The debris was retained on the core plate until melting core plate as conventional model, but the model was improved based on results of XR2-1 experiment so that the debris felled to lower plenum by considering a other process of the fall of the debris. After falling debris, by the model of reactor pressure vessel failure improved, the behavior of debris falling from reactor pressure vessel was influenced. The improved model was considered not only the failure of reactor pressure wall but melting of instrument pipe penetrated to the inside of reactor pressure vessel. Applying these improved models, the results of the simulation after operating sea water injection was shown.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
