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:
ssure Vessel Base (Plate) Materials ......................................... 9 4. TRANSIENT SELECTION ............................................................... I I 4.1 Plant-Specific Transients .......................................................... I 4.2 Bounding Transients .............................................................. 1 D. IM PLEM ENTATION ........................................................................... 11 REFERENCES ........................................................................................ 12 APPENDIX A: Examples ............................................................................. A-1 APPENDIX B: Computation of Stress Intensity Factors ...................................................... B-l REGULATORY ANALYSIS ............................................................................ R-l m.° A. INTRODUCTION > Appendix 0. Fracture Toughness Requirements" to 10 CFR Part 50, "Domestic .Licensing of Production and Utilization Facilities," requires, in part, that the reactor vessel betline materials ". . must have Charpy upper- shelfnergy of no less than 75 fl-lb (102J) initially and must maintain upp•r-shelf energy throughout the life of the vessel of no less than 50 ft-lb (68J), unless it is demotrated in a manner approved by the Director, Office of Nuclear Reactor Regula tion, that lower values of upper-shelf energy will provide margin of safety against fracture equivalent to those required by Appe.ndx 0 of the ASME Code."' Charpy uppcr-shelf energy is defined in ASTM E 185-79 (Ref. 1) and -82 WR 2), which are incorporated by reference in Appendix KL "Reactor Vessel Material Surveillance Program Require ments to 10 CFR Part 50. This guide describes general procedures acceptable to the NRC staff for demonstrating equivalence to the margins of safety in Appendix 0 of the ASME Code (Ref. 3). Several examples using these proc dures are presented in Appendix A to this guide and in more detail in