CORVIS. Investigation of light water reactor lower head failure modes Original Research Article

The project CORVIS (Corium Reactor Vessel Interaction Studies) is a research programme for the experimental and analytical investigation of a possible failure of the pressure vessel of a light water reactor during an assumed core melt accident. The applied methods of the experimental technique, the metallurgical investigations and the computational analysis are described. Two recent melting experiments are presented in detail. The first experiment was carried out on a steel plate 100 mm thick representing a pressure vessel lower head without penetrations. The second experiment was performed on a steel plate of the same thickness but representing a boiling water reactor lower head carrying a tube penetration in the form of a drain line. Reported are the phenomenology of these experiments, the results of the metallurgical post-test examinations and the computational reconstruction of the observed heat transfer and ablation phenomena in a stagnant and in a turbulent melt. Further, the results of three earlier tests, on a smaller scale, are presented.