“Use of Mechanical Stress Improvement for Weldments with Cracks” J. S. Porowski, W. J. O’Donnell, M. L. Badlani, and E. J. Hampton, Proceedings, SMIRT Post Conference Seminar No. 2, “Assuring Structural Integrity of Steel Reactor Pressure Boundary Components,” Taipei, R. O. C., August 26-28, 1991.
The Mechanical Stress Improvement Process (MSIP) has been applied to protect weldments of boiling Water Reactor piping systems since 1986. More than 60 weldments in 20 plants including 186 nozzle and safe-end weldments are protected to date. MSIP is a proven technology recognized by the NRC in NUREG 0313 as a stress improvement method. The frequency of UT examination for stress improved weldments can be significantly reduced compared to the inspections required for as-welded joints. The use of MSIP to arrest small depth cracks detected in their early stages should provide an attractive alternative to pipe replacement or costly repairs.