Post-Irradiation Examination of the 37M Fuel Bundle at Chalk River Laboratories (AECL)

Abstract

The modified 37-element (37M) fuel bundle was designed by Ontario Power Generation (OPG) to improve Critical Heat Flux (CHF) performance in ageing pressure tubes. A modification of the conventional 37-element fuel bundle design, the 37M fuel bundle allows more coolant flow through the interior sub-channels by way of a smaller central element. A demonstration irradiation of several fuel bundles was completed in 2011 at OPG’s Darlington Nuclear Generating Station to confirm the suitability of the 37M fuel bundles for full core implementation. In support of the demonstration irradiation, one intact 37M fuel bundle and 14 loose fuel elements were examined in the Chalk River Laboratories Hot Cells. Inspection activities included: • Bundle and element visual examination • Bundle and element dimensional measurements • Verification of bundle and element integrity • Internal Gas Volume Measurements The inspection results were comparable to that of conventional 37-element CANDU® fuel previously examined in the hot cells. Fuel performance parameters of the 37M DI fuel bundle and 14 fuel elements were within the range observed for similarly operated conventional 37-element CANDU® fuel. Based on these Post Irradiation Examination (PIE) results, 37M fuel performed satisfactorily.