POST TEST CALCULATIONS OF NOKO EXPERIMENTS WITHIN THE FRAMEWORK OF A EUROPEAN RESEARCH-PROGRAM

Within the framework of the ''European Boiling Water Reactor Research and Design Cluster Project'', six test series with an emergency conden ser test bundle were performed in 1996. Within the ''Physics and Therm ohydraulic Complementary Action'' to the Cluster Project the German Fo rschungszentrum Rossendorf and the French Commissariat a l'Energie Ato mique have calculated 9 tests and an additional blind test of NOKO bun dle experiments in 1997. These post test calculations were carried out using A THLET and CATHARE2 computer codes. The comparison of the expe rimental and computational results (e.g. for mass flows temperatures, capacities pressure drops) show an excellent agreement. Despite the go od prediction of global parameters, a variation of local parameters (e . g. film velocity void fraction, heat flux) can be observed. This can be explained by the significant effect of the tribe wall conduction i n controlling the hear transfer.