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:
stified on a case-by-case basi. Otherwise, the material's J-integral fracture resistance may be determined from Equation 17, developed in Reference 10: J4=(0) {C)(Aa) 0exp[C3 (Aap])C 4 \1 (17) 1.161-8 The coefficients in Equation 17 for each material type are discussed below. As noted earlier, the net-section thickness, B., of ASTM E 1152-87 (Ref. 9) compact-tension (CT) specimem to be considered is specified as I inch. In addition to the Charpy (CVN) models discussed in this guide, Refer ence 10 contains two other models, namely the Copper Fluence (Cu-ft) models and the pre-inradiation Charpy (CVN) models, which may be used to determine the mate rial's J-R curves. 3.1 Welds Made Using Linde 80 Flux For analyses addressing Service Levels A, B, and C, a conservative representation of the J-R curve is obtained by setting the margin factor, MF = 0.648. For analyses addressing Service Level D. set MF = 1.0. Cl = exp[-3.67 +1.45 ln(CVh) -0.00308T7 C2 = 0.077 + 0.116 InCl C0 = -0.0812 - 0.0092 lnCI C4 = -0.5 (18) (19) (20) (21) 3.2 Generic Reactor Pressure Vessel Welds For analyses addressing Service Levels A, B, and C, a conservative representation of the J-R curve is obtained by setting the margin faictor, M - 0.629. For analyses addressing Service Level D, set M - 1.0. C1 = exp[-4.12+1.49 ln(CYh)-0.00249T C2 = 0.077 + 0.116 InCl C3 = -0.0812 - 0.0092 InCI C4 = -0.5 (22) (23) (24) (25) 3.3 Reactor Pressure Vessel Base (Plate) Materials The elastic-plastic fracture toughness of plate materials may be relatively high or quite low, depnding on a variety of chemical, metallurgical, and thermo-mechanical processing variables. The statistical analyses reported in Reference 10 included only materials that exhibited a J-R curve with a significantly rising slope, ic., the higher toughness materials. However, test results reported in NUREG/CR-5265, "Size Effects on J-R Curves for A-302B Plate" (Ref. 15), clearly show J-R curves with very little, if any, increase in slope.