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:
ve a comparison of the applied J-integral to the material's J-integral fracture resis tanc at a ductile flaw extension of 0.1 inch and a determina tion that this flaw would be stable under the applied loading. Procedures are detailed below for (1) calculating the applied J-integral for Service Levels A and B flaws and loading conditions and (2) determining that the slope of the material's J-integral resistance curve is greater than the slope of the applied J-integral versus crack depth curve at the equillritum point on the J-R curve where the two curves intersect, as illustrated in Figure 1. 2.1.1 Calculation of the Applied J-Integral The calculation of the applied J-integral consists of two steps: Step 1 is to calculate the effective flaw depth, which includes a plastic-zone correction, and Step 2 is to calculate the J-integral for small-scale yielding based on this effective flaw depth. Step I For an axial flaw with depth'a equal to (0.25t + 0. 1 in.), calculate the stress intensity factor from internal pressure, p, with a safety factor, SF, on pressure equal to 1.15, using Equation 6: K F=(s) p, [I + (Rl11] (7c)°3 F, (6) F, = 0.982 + 1.006(a/t)2 This equation for K,"" is applicable to 0.05 - a/t < 0.50, and it includes the effect of pressure acting on the flaw faces. 1.161-4 K 0) E 4) S -- Evaluation Point Crack Extension, Aa Figure 1. Comparison of the Slope of the Applied J-Integral and J-R Curve. 1.161-5 For a circumferential flaw with depth 'a equal to (0.25t + 0. 1 in.), calculate the stress intensity factor from internal pressure, p., with a safety factor, SF, on pressure equal to 1.15, using Equation 7: K4'- = ($F)p. [ I + (R,/(2t1)) ] ( a)°0'SF, 7 F2 = 0.885 + 0.233 (aft) + 0.345(a/t)62 This equation for Kip' is applicable to 0.05 :c a/t s 0.50, and it includes the effect of pressure acting on the flaw faces. For an axial or circumferential flaw with depth 'a' equal to (0.25t + 0.1 in.), the "steady-state" (time independent) sess intensity factor from