摘要：The various post irradiation examinations were carried out at Pakistan Institute of Nuclear Science and Technology (PINSTECH) for the first time in 1991 -93 on a fuel bundle which was fabricated in Pakistan and was irradiated at Karachi Nuclear Power Plant (KANUPP) up to a maximum burn-up of 6947 MWD/TeU. This bundle had its end plates in damaged condition. Attempts were made to determine the cause of their damage during microstructural study of the material. Therefore metallographic examinations were carried out in great detail. The measurements of oxide layer thickness and hydride concentrations were main areas of study. The study revealed the hydridation and severe oxidation effect on the end plate material. There was found to be an increase in the concentration of radial hydrides which might have resulted in the embrittlement of material and thus caused the failure of end plates.
