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:
h and for the temperature history, in Figure A-I, at a crack depth of (0.25t'-O.1) inch A study ofFigure A-2 shows an interesting trend that the crack initiation is predicted to take place at about 45 minutes into the transient (with crack-tip temperature of 500F¶) where the applied-J value (-- 445 in.-lb/i. 2) is less than the peak steady-state value and is just equal to the material's J-R curve at CVN value of 40 ft-lb. Thus, the more detailed analysis results in a lower CVN value that satisfies the acceptance criteria. In order to satisfy Equation 2, with a safety factor of 1.25 on accumulation pressure, Figure A-3 shows that CVN value should be greater than or equal to 41 ft-lb. This is significantly lower than the 47 fi-lb value obtained by using the steady-state applied J-integral approach for analyzing transients with constant cooldown rates. 'F.A Simoaen gt at, VISA-HI - A Computer Code for Preddting the Probabfity oafReacdr Presmer Vene F&Rlhe, USNRC. NUREOICR-4436, March 1926. A-1 Example 2 (Levels C and D Loading, PWR Vessel) The problem statement was presented in a meeting of the ASME Section XI Working Groups on Flaw Evaluation and Operating Plant Criteria (in Louisville, Kentucky, on December 1, 1992), where results of the analyses were compared by the participants. The vessel geometry and material properties are: PWR vessel internal radius, R4 - 90.0 inch; A-533B plate material thickness, t = tsu - 9.0 inch; Cladding thickness, tI, = 0, Rf& = 10 Copper, Cu = 0.35wt%; Nickel, Ni = 0.3 wt%; Initial RTm. = 0.01F Pre-irradiated CVN, - 108 R-lb (L-T orientation) Surface fluence, •t = 3.0E19 n/cm2 Flaw orientation = Axial, in plate material; Flaw aspect ratio 6 to I Fluid temperature at vessel surface, T(tm) - [550 - 25011 - exmg- 0.1 tm)W]'F with time, tin, in minutes. Heat transfer coefE = 320 BTU/br-t-OF; Thermal diffusivity = 0.98 in.2/min Elastic modulus, E = 28E3 ksi; Poisson's ratio, v =0.3; a f S&IE-6 inlm.-0F Yield stress, oy = 80 ksi; Flow