DEVELOPMENT OF A LOCA ANALYSIS CODE FOR THE SUPERCRITICAL-PRESSURE LIGHT-WATER COOLED REACTORS

The supercritical-pressure light water cooled reactors aim at cost red uction by system simplification and higher thermal efficiency, and hav e flexibility for the fuel cycle due to technical feasibility for vari ous neutron spectrum reactors. Since loss-of-coolant accident (LOCA) b ehavior at supercritical pressure conditions cannot be analyzed with t he existing codes for the current light water reactors, a LOCA analysi s code for the supercritical-pressure light water cooled reactor is de veloped in this study. This code, which is named SCRELA, is composed o f two parts: the blowdown and reflood analysis modules. The blowdown a nalysis module is designed based on the homogeneous equilibrium model. The reflood analysis module is modeled by the thermal equilibrium rel ative velocity model. SCRELA is validated by the REFLA-TRAC code, whic h is developed in the Japan Atomic Energy Research Institute based on TRAC-PF1. A large break LOCA of the thermal neutron spectrum reactor ( SCLWR) is analyzed by SCRELA. The result shows that the peak clad temp erature (PCT) is nearly 980 degrees C about 60 s after the break and t he PCT position is quenched at 170s This means that PCT is sufficientl y lower than the safety limit of 1260 degrees C. In conclusion, the de veloped code shows the safety of SCLWR under the large break LOCA, and is expected to be applied to LOCA analysis of other types of the supe rcritical-pressure light water cooled reactors. (C) 1998 Elsevier Scie nce Ltd. All rights reserved.