Use of Mechanical Stress Improvement for Weldments with Cracks

“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.

Mechanical Stress Improvement Process; MSIP; piping systems; NUREG 0313; stress improvement method

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.


Company President, Bill, Sr. is active on the ASME Subcommittee on Design, and serves as a Contributing Member of the ASME (BPV III) Working Group on Fatigue Strength. He has also co-authored numerous papers on various engineering topics.

O’Donnell Consulting performs engineering design and analysis to ASME Code including B&PV Section VIII Division 1 and 2 – as well as the Power & Process Piping Codes. 

(412) 835-5007

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