Impact Analysis on the Collective Dose Caused by Zirconium Oxide Peeling off from Fuel Cladding

Deposition of corrosion and activation products contributes to 90% of the occupational exposure of workers during the operation of pressurized water reactor nuclear power plant (including full power operation and refueling outage). Peeling off of zirconium oxide from fuel cladding is found during the outage of a power plant in China and will thus increase the collective dose. Impact on the collective dose is evaluated through: a) calculation of activated source term using ORIGEN according to the material composition, b) deduction of distribution in primary coolant based on the feedback from power plant with similar phenomenon, and c) calculation of the resulted dose rate. Result shows that peeling off of 15 g zirconium oxide could produce approximately 6%–15% increment to the collective dose.