Document: NRC Regulatory Guide
Document ID: 2704425a-c58a-45c4-93ab-8761721c3e7a
Document Type: regulatory_guide
Title: Evaluation of Reactor Pressure Vessels with Charpy Upper-Shelf Energy Less Than 50 Ft-Lb
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740038.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.161
CFR Part: 
CFR Title: 

Content:
te total depth not to exceed 1.0 inch (2.54 cm) and with an aspect ratio of 6-to- I surface length to flaw depth. A smaller maximum flaw depth may be used on an individual-cas basis if justified. For these evaluations, two criteria must be satisfied. 11.1 The crack driving force must be shown to be less than the material toughness as given by Equation 3: aWpped < Jo.1 (3) 1.161-3 1, The material's yield stress (ksi). v Poisson's ratio (dimensionless), specified as 0.3. C. REGULATORY POSITION 1. ACCEPTANCE CRITERIA J~vpied < J0.1 where J., is the J-integral value calculated for the postu lWted flaw in the beltline region of the reactor vessel under the governing Service Level C condition, with a safety factor of 1.0 on the applied loading. J01 is the J-integral characteristic of the material resistance to ductile tearing (JQ..), as denoted by a J-R curve test, at a crack extension of 0.l inch. 1.,2 The flaw must also be stable under ductile crack growth as given by Equation 4: 8a aa (4) (with load held constant) at i'amp~~ = Jtmlt,1 where Jo is calculated for the postulated flaw under the governing Service Level C condition, with a safety factor of 1.0 on the applied loading. The material's J-integral fracture resistance hould represent a conservative estimate of the data for the vessel material under evaluation (i.e., mean - 2 standard deviations). The J-integral resistance versus crack growth, J-R curve, is defined in Regulatory Position 3 of this guide. Determination of the appropriate service level condi tions is discussed in Regulatory Position 4 of this guide. 1.3 Level D Condition When the Charpy upper-shelf energy of the base metal is less than 50 ft-lb, postulate both axial and circumferential interior flaws and use the toughness properties for the corre spending orientation. When the Charpy upper-shelf energy of any weld material is less than 50 ft-lb, postulate an interior semi-elliptic surface flaw with the major axis oriented along the weld of concern