Document: NRC Regulatory Guide
Document ID: a2b67b51-f5fe-4c86-a879-f0e439601f7f
Document Type: regulatory_guide
Title: Format and Content of Report for Thermal Annealing of Reactor Pressure Vessels
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740052.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.162
CFR Part: 
CFR Title: 

Content:
values of reference temperature (RTNDT) and Charpy upper-shelf energy, respectively, at plant restart. 3.1.6.4 Sub-size Charpy Specimens. Sub-size Charpy specimens can provide very useful information concerning the toughness of the material and the re covery of irradiation embrittlement by annealing. Data from sub-size Charpy specimens is not uniquely corre lated to data from full-size Charpy specimens in an absolute sense, but quantities such as irradiation embrittlement shift and annealing recovery can be eva luated from sub-size specimen data. Although some work has been under way in the United States In this area using several sub-size Charpy specimen designs, there is no consensus in the U.S. technical community or the nuclear industry as to a preferred specimen de sign or an appropriate correlation method. 1.162-13 The assurance program should describe the over all test plan for the use of sub-size Charpy specimens, including test specimen design and test procedures. In addition, the assurance program should describe the method proposed for quantitative use of the sub-size Charpy specimen data in evaluating percent recovery, including any experimental demonstration validating the method. 3.2 Reembrittlement Trend Assurance Program As specified in the thermal annealing rule (10 CFR 50.66(b) (3) (ii) (B)), the reembrittlement trend of both RTNDT and Charpy upper-shelf energy is to be estimated to establish the projected embrittlement at the end of the proposed period of plant operation, and is to be monitored during post-anneal reactor opera tions to confirm these estimates, using a surveillance program that conforms to the intent of Appendix H of 10 CFR Part 50. An appropriate method for estimating the reembrittlement trend is using a "lateral shift" method. For the "lateral shift" method, the reem brittlement trend is the same as the embrittlement trend used for the pre-anneal operating period, regard less of whether the embrittlement was determined using the