Planning of the ATWS Simulation Tests by using Experimental Fast Reactor JOYO

Oyama, Kazuhiro; Kuroha, Takaya*; Takamatsu, Misao ; Sekine, Takashi 

A study of passive safety test using JOYO has been carried out to demonstrate the inherent safety of sodium cooled fast reactors. In this study, emphasis was placed on the improvement of the accuracy of plant kinetics calculations. The Mimir-N2 analysis code, developed to analyze JOYO plant kinetics, was selected as the standard code for predicting plant behavior during transients.Mimir-N2 was previously modified for MK-III core in 2001, 2002. Then, it implemented MK-III performance testing estimate analysis. The MK-III performance test included manual reactor shutdown test and loss of power supply test etc. as transient tests. In order to further improve the accuracy of the calculation, the Mimir-N2 heat transport system models of the reactor vessel upper plenum, the hot leg of secondary heat transport system and the dump heat exchanger were modified based on the results of the MK-III performance test in 2003.In this year, it stores up to get the prospect to have paid to the implementation of the UTOP, the ULOF test which is planned as the passive safety test, it evaluated about the plant structure and UTOP, the ULOF analysis for the parameter of which was the investing reactivity and so on by the Mimir-N2 analysis code. As a result, we could work out the testing condition which has prospect.