Ontario Hydro High Burnup Power Reactor Fuel Performance

Abstract

Ontario Hydro has irradiated more than 100 37-element fuel bundles to greater than 400 MWhlkgU. Only a small number of bundles have reached burnups in excess of 600 MWh/kgU. In this case, the sample is too small to form a statistical data base. The performance assessment must then rely on detailed hot-cell examination results to provide a fundamental understanding of the significant parameters. A significant performance deterioration was found on Bruce bundles with burnups over 600 MWhlkgU. Most of the outer elements were defective, fission gas release was up to 28%, and diameter strains up to 2% were measured. This paper summarizes Ontario Hydro's high burnup data base and presents hot-cell examination highlights of fuel irradiated up to 800 MWh/kgU.