Cover plate welding sequence and shape rationality simulation analysis on wall cracks of stainless steel spent fuel pool

摘要

The wall of spent fuel pools is prone to pitting or electrochemical corrosion owing to a long-term service in acidic media, where a penetrating cracking may occur in severe cases. Moreover, totally replacing the spent fuel pool causes huge economic losses. Thus, cover plate welding is used to repair the cracked region of spent fuel pools using the 'fitness for service' principle. The finite element method is used to simulate and analyse the temperature and stress fields during the repair process of cover plate welding to guarantee that the repair process does not cause new dangerous effects on the cracked region. In this study, we used self-fusion gas tungsten arc welding (GTAW) to cover defects with square and circular patch plates. The modified double-ellipsoid heat source model is derived for cure welding. The effects of two patch plate shapes and different welding sequences on the temperature and stress fields during the welding process were compared using numerical analyses. Finally, a reasonable patch board shape and welding sequence were determined.