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:
method, the vessel percent recovery would be calculated by multiplying the percent recovery de termined from Equations 1 and 2 for the vessel by the average ratio adjustment. Values of Rt and RUSE de termined from surveillance data may not exceed 100. Once suitable values of Rt and RUSE have been determined from the surveillance data, the post-anneal reference temperature (RTNDT) and Charpy upper shelf energy are evaluated using Equations 3 and 4: RTNDT(A) = RTNDT + ARTNDT x (100 - W) / 100 (Equation 3) CvUSE(A) = CvUSE(u) [I - D x (100 - RUSE)/100001 (Equation 4) where RTNDT(A) = reference temperature, RTNDT, of the material in the post anneal condition in OF, RTNDT(U) = reference temperature, RTNDT, of the material in the preservice or unirradiated condition in °F, ARTNDT = mean value of the transition temperature shift, or change in RTNDT, from irradiation (before annealing) in °F, Rt = percent recovery of ARTNDT from annealing, CvUSE(A) = Charpy upper-shelf energy of the material in the post anneal condition in ft-lb, CvUSE(u) = Charpy upper-shelf energy of the material in the preservice or unirradiated condition in ft-lb, D = percent decrease in Charpy upper-shelf energy from irradiation (before annealing), and RUSE = percent recovery of Charpy upper-shelf energy from annealing. 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 the ini tiation of continued plant operation. 3.1.6.2 Irradiated Vessel Material Method. Since the Charpy data evaluated by this method repre sent the surface or near-surface properties of the plate, weld, or forging, the measured values cannot be used directly to represent the plate or forging 1/4T or weld bulk properties as called for by Regulatory Guide 1.99, Revision 2 (Ref. 21). However, evaluations of the pre anneal and the post-anneal properties of the sample removed from the vessel