Magnetic Pulse Welding of D9 Steel Tube to SS316LN End Plug

The integrity of the fuel clad plays a pivotal role in the performance and safety of a nuclear reactor. The end plug of a fuel pin is conventionally joined to the clad tube using fusion welding techniques in fast breeder fuel fabrication routes. In the present study, joints between the D9 clad tubes and end plugs of SS 316LN were successfully developed using magnetic pulse welding (MPW). For this purpose, a 70 kJ,25 kV MPW machine, tool coil, field shaper and fixtures were developed. Process parameters were optimised by trial and error to give optimum results. The joints were qualified using several destructive and non-destructive welding methods. The leak rate of the joints was found to be 1.5 × 10 –10 Pa.m 3 /s, and the microstructure of the joint interface showed a wavy morphology typical of sound MPW joints. X-ray computer tomography of the MPW joints showed uniformity in the joints. The quality of the joints remained unaltered even after the internal hydraulic pressure burst test. Therefore, the present work demonstrates the capability of MPW, a solid-state joining technique, to serve as an alternate method for joining the end plugs to the clad tubes in the fuel fabrication of a fast breeder reactor.