Measurement of the residual stresses in a PWR Control Rod Drive Mechanism nozzle

Harry Coules*, David Smith

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

1 Citation (Scopus)
334 Downloads (Pure)

Abstract

Residual stress in the welds that attach Control Rod Drive Mechanism nozzles into the upper head of a PWR reactor vessel can influence the vessel's structural integrity and initiate Primary Water Stress Corrosion Cracking. PWSCC at Alloy 600 CRDM nozzles has caused primary coolant leakage in operating PWRs. We have used Deep Hole Drilling to characterise residual stresses in a PWR vessel head. Measurements of the internal cladding and nozzle attachment weld showed that although modest tensile stresses occur in the cladding, the attachment weld contains tensile residual stresses of yield magnitude. Despite the large dispersion of residual stress data for nozzle attachments of this type, all available data suggest that assuming a residual stress profile bounded by the weld material's yield stress would be conservative for assessment purposes.

Original languageEnglish
Pages (from-to)16-24
Number of pages9
JournalNuclear Engineering and Design
Volume333
Early online date24 Apr 2018
DOIs
Publication statusPublished - Jul 2018

Keywords

  • Residual stress
  • Deep Hole Drilling
  • Pressurized Water Reactor
  • Cladding
  • Control Rod Drive Mechanism

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