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:
thermal loading. As with the Service Level A and B criteria, for Service Level C it must be demonstrated that the applied J is less than the material's fracture resistance at a crack extension of 0.1 inch, and that the flaw must be stable under the applied loading. Procedures are described below for (1) determining the applied J-integral for Service Level C flaw and loading conditions and (2) determining that the slope of the material's J-integral fracture resistance, J-R curve, is greater than the slope of the applied J-integral versus crack depth curve. 2.2.1 Calculation of the Applied J-Integral The calculation of the applied J-integral consists of two steps: Step I 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 ) Postulate a series of flaws with depths ranging up to cladding thickness plus 0. 1 times the base metal wall thick ness, but not exceeding 1.0 inch (2.54 cm). The number of flaws and the specific flaw sizes to be postulated should be m icrient to determine the peak value of the applied J-integral over this size range. For each of these postulated flaws, the analysis flaw size 'a' should be the sum of the postulated flaw size plus 0. 1-inch ductile crack extension. For axial flaws, at each analysis flaw size, calculate the stress intensity factor arising from internal pressure, p., with a safety factor, SF, on internal pressure equal to 1.0, using Equation 11: K4',"'= (sF9p. [ I÷+(R/t ) ] ( 7raf5F, 11 F1 =0.982+1.006(alt'?; with 0.05<a/tr'0.5 For circumferential flaws, at each analysis flaw size calculate the stress intensity factor arising from internal pressure, p. with a safety factor, SF, on pressure equal to 1.0, "using Equation 12: K4p -=(S•)p,(. I +R/(2t)](a)O.SF2 (12) F2 = 0.885.0233(a/ft)+0.345(a/t)2 These equations for Kip'"w are valid for 0.05 s at' s 0.5, and include the effect of pressure acting