Impacts of Burn-up Measurement Errors on Discharge Burn-up of PB-HTR

摘要

The burn-up measurement is an essential procedure for the multi-pass refueling strategy of pebble bed high temperature reactors (PB-HTRs). The fuel pebbles unloaded from the core bottom are determined either to be recycled to the core top or to be stored as spent fuels according to the results of comparison between the measured burn-up values and a pre-defined burn-up threshold. Due to the random feature of pebble flow within the core, the discharge burn-up of multi-pass fuels of PB-HTR has a statistical distribution. On the other hand, the burn-up measurement by using gamma spectroscopy presents measurement errors, including the random errors and the systematic errors, which will both impact the distribution of discharge burn-up. In this work, the impact of burn-up measurement errors on the actual distribution of discharge burn-up and further on the neutronics features of equilibrium core is investigated.