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:
aterial's J-integral fracture resistance at a ductile flaw growth of 0.10 in. (in.-lb/'in). KI& The mode I stress intensity factor caused by the radial thermal gradient through the cladding applied to the vessel inner surface, calculated with no plastic zone correction (ksi Ain.). KV The mode I stress intensity factor caused by the internal pressure, calculated with no plastic-zone correction (ksi 4tin.); K,.' and K.m are the axial and circumferential values, respectively. 4ý K,, calculated with a plastic-zone correction (ksi fin.). K1 The mode I stress intensity factor caused by the radial thermal gradient through the vessel wall, calculated with no plastio-zone corroection Y.; K. calculated with a plastio-zone correction (ksi 'in.). p Internal pressure (ksi). p. The maximum accumulation pressure as defined in the plant-specific Overpressure Protection Report, but not eceding 1.1 times the design pressure (ksi). 1• The inner radius of the vessel (in inches). SF The safety factor (dimensionless). t The wall thickness of the vessel's base metal (in inches). The sum of the vessel wall thickness, t, and the cladding thickness, t.L (in inches). tlL The thickness of the stainless steel cladding applied to the vessel inner surface (in inches). T Metal tWeraturp, at crack-tip, used in the analy sis ('F). 1.161-2 WF The margin factor = 2 standard deviations on test data (dimensionless). A reference material's flow stress, specified as 85 ksi in ASME Section XI, Appendix K (Ref. 8), on Charpy upper-shelf energy. of The following criteria are acceptable to the NRC staff for demonstrating that the margins of safety against ductile fracture are equivalent to those in Appendix 0 to Section III of the ASME Code. Licensees may follow this regulatory guide to determine the equivalent safety margins, or they may use any other methods, procedures, or selection of materials data and transients to demonstrate compliance with Appendix o to 10 CFR Part 50. If licensees choose to