The pebble bed high-temperature gas-cooled reactor(PB-HTGR)is characterized by continuous online refueling.The fuel ball flows slowly in the core of the reactor.The VSOP code,which is widely used in engineering design,employs an approximate and average refueling method to simulate the process,tending to diminish the randomness of the pebble flow of PBR to some extent.In this paper,a new approach of random refueling based on VSOP code is proposed,and it improves the core refueling model and focuses on the impact of the average merging effect of discharging fuel.The results show that the random refueling approach can provide a more refined discharge fuel burnup probability distribution,and the average merging effect of discharging fuel tends to the broadening and overlapping of burnup peaks.
Pebble bed high-temperature gas-cooled reactorVSOPRandom refuelingAverage merging effect of discharging fuelDischarge fuel burnup probability distribution