Interpretation of the CABRI-RAFT RB1 and RB2 tests through detailed date evaluation and PAPAS-2S code analysis

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The CABRI-RAFT RB1 and RB2 tests were aiming at a study on impact of fuel pin failure under an overpower condition leading to fuel melting. Using a special technique, combination of through-cladding failure and fuel melting was realized.In the RB1 rest, fuel ejection was prevented under a limited fuel melting condition. On the other hand, significant fuel melting was applied in the RB2 test so as to get the fuel ejection, thereby obtaining information on the fuel ejection behavior. Interpretation for these tests through the detailed experimental data evaluation and the PAPAS-2A code analysis is performed in this study. Through this study, it is indicated that molten fuel ejection can be prevented with the low smear density fuel as far as the fuel melting is not large for a slit-type cladding defect ct. Fuel ejection becomes possible in the case of significant fuel with a very thin solid fuel shell surronding the molten fuel cavity. However, the r