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:
he 1/4T location, CvUSE(A) = Charpy upper-shelf energy of the material in the post-anneal condition, for the 1/4T location of plate and forging, or the weld bulk properties in ft-lb, CvUSE(u) = Charpy upper-shelf energy of the material in the preservice or unirradiated condition, for D CVSA the 1/4T location of plate and forging, or the weld bulk properties in ft-lb, = percent decrease in Charpy upper-shelf energy from irradi ation embrittlement, for the 1/4T location of plate and forging, or the weld bulk properties, = from the measured surface data, the Charpy upper-shelf energy for the pre-anneal condition in ft-lb, = from the measured surface data, the Charpy upper-shelf energy for the post-anneal condition in ft-lb. The values of RTNDT(A) and CvUSE(A) calcu lated using Equations 5 and 6 should be used as the values of reference temperature (RTNDT) and Charpy uppershelf energy, respectively, at the initiation of continued plant operation. If the samples removed from the vessel beitline do not come from the vessel peak flux location, the vessel embrittlement and the annealing recovery will not be as great as that for the vessel peak flux location, and Equations 5 and 6 should underestimate the percent recovery of the vessel. In such cases, the assurance program should describe the procedures used to evalu ate percent recovery for the vessel materials from the measurements resulting from this method. 3.1.6.3 Computational Method. For the compu tational method, the postanneal initial RTNDT and Charpy upper-shelf energy values for each beltiine ma terial should be evaluated using Equations 3 and 4, us ing the values of Rt and RUSE from Equations 2 and 1. The values of RTNDT(A) and CvUSE(A), calcu lated using Equations 3 and 4, respectively, should be used as the 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