The Induction Heating Stress Improvement (IHSI) technique is regarded as one of the most effec tive remedies for intergranular stress corrosion cracking (IGSCC) cocuring in the heat affected zone (HAZ) of susceptible stainless steel in some boiling water reactor piping systems. In this process, cooling water must flow at a velocity high enough to keep the inside surface of the pipe relatively cool, creating a high temperature gradient through the pipe wall. However, nuclear plant pipings, where

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... forced flowing during this process may be difficult, have been welded. This paper presents computer simulation analyses and experimental verifications of post-IHSI residual stress distribution of the welded portion of a nozzle with a thermal sleeve, where forced water cooling is difficult. From these analyses and experiments a new IHSI technique is developed. This technique consists of new heating method which has tempera ture grandient through both the pipe wall and longitudinal direction.