The Pressurized Heavy Water Reactors (PHWR) in India use nuclear fuel bundles consisting of 19 fuel elements. In a failed fuel bundle from Kakrapar Atomic Power Station (KAPS-II), two outer fuel elements were observed to have cracked near the end cap weld. Neutron radiography indicated loss of fuel from the first pellet and presence of zirconium hydride blister in the clad. Ultrasonic and eddy current testing of the clad inside the hot cells confirmed the presence of multiple fine axial cracks up to mid length of the fuel pin. The end plug weld was inspected by ultrasonic testing to detect lack of fusion defects. It was found that the weld had lack of fusion and corresponding a through the wall material defect in the end plug body. The tight material defects from the fabrication stage opened up permeating coolant inside the fuel pin during reactor operation and subsequent clad failure due to hoop stress. The hydrogen produced from the coolant oxidation reaction at the entry site, travelled to the other end of the fuel pin and hydrided the inner ring as well as end plug weld region. Hydride blister formed in the weld region had also cracked partially. Both end plugs of the failed fuel pin had linear fabrication defects in the same axial orientation. This paper presents the investigation of clad failure using multiple NDT techniques.