Towards identification of the suitable core locations for manufactured qualification of Candu fuel

This work is carried out in cooperation with atomic energy of canada limited (AECL) in the framework of developing local capabilities in the field of fuel engineering and performance analysis. This paper belongs to achievements in the analysis and evaluation of Candu fuel performance. The Candu - 6 fuel defect database are presented and analyzed. The relevant characteristics of each fuel defect mechanism are discussed. Major contribution to fuel defects are attributed primarily to manufacturing flaws. These flaws include: (a) fuel elements that have porous end caps, (b) elements with incomplete closure welds, or (c) elements containing hydrogenous material that introduced during fabrication processes. Taking one of Candu-6 nuclear reactors as a reference, the operating conditions at the start of operation and after 6 year operation are used in assessing the parameters that may promote flaws deterioration. The distribution of manufacturing defects throughout the core in axial and radial directions have shown that some locations are more likely to promote deterioration. These locations are suggested as convenient ones to test and define the quality of new fuel bundles. On the other hand, fuel bundles; predicted to have manufacturing flaws; may be restricted to be loaded in these sites to protect the bundles from accelerated degradation. 6 fig