TESTING 3-D NODAL CODES SIMULATE-3/5 FOR REFUELINGSHUTDOWN MARGIN PREDICTIONS WITH CASMO-5M

摘要

Reactor shutdown refueling is a crucial task for BWR operations. In this paper, based on a realistic BWR core refueling sequence, the SIMULATE-3 and SIMULATE-5 shutdown margin (SDM) predictions are benchmarked against CASMO-5M results. The 2-D core in this exercise is established from the middle plane of a typical 748-bundle BWR core. There are thousands of fuel move steps from the end of previous cycle to the beginning of next cycle, most of which are so-called partially loaded core configurations where empty fuel locations are filled with water. During this process, eigenvalue predictions from CASMO-5M and SIMULATE-3/5 are compared for the all-rod-in (ARI) case and the ARI except the maximum-worth rod (ARI-M) case. Based on more advanced neutronic models, SIMULATE-5 shows sizable improvements in agreeing with the CASMO-5M reference solution over the SIMULATE-3 results for partially loaded cores.