Calculation of Radiation Dose Rates in a Water Layer in Contact with Used CANDU UO₂ Fuel

Alpha, beta, and gamma dose rates in water, in contact with the reference used fuel in the Canadian Nuclear Fuel Waste Management Program (i.e., Bruce A CANDU fuel, burnup 685 GJ/kg U), are calculated as a function of cooling time. Procedures to calculate the dose rates for used CANDU fuels of different burnups from results obtained for the reference fuel are described. These procedures can be adapted to estimate dose rates for fuels other than CANDU fuel. The dose rate information is needed to compare the results of leaching and corrosion experiments, conducted by different groups, with used fuels of different burnups and/or cooling times and to predict the effects of radiolysis of groundwater on used fuel oxidation and dissolution in a disposal vault.