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:
= standard deviation of ARTNDT in OF, 3.2.1.3 Reembrittlement of the Charpy Upper Shelf Energy. The reembrittlement of the Charpy upper-shelf energy is evaluated using the same embrittlement trend as the pre-anneal operating peri od, with a lateral shift. For the pre-anneal operating period, Revision 2 of Regulatory Guide 1.99 (Ref. 21) gives upper-shelf energy decrease in a graphical form only. Merkle (Ref. 22) developed equations that accu- for base metals: 1 - (CvUSE(A)/CvUSE(u)) 14.223 for weld metals: 4.223 I 1- (CvUJSE(A)/CvUSE(u)) [ 100 Cu + 14 ] 1.162-16 K K`1 the upper bound: 1 -(CvUSE(A)/CvUSE(u)) I6.658 f' "42.39 (Equation 15) For both weld metal and base metal, the correct value of fs is the larger of the values from the appropri ate equation for the material type and the upper bound equation. Reembrittlement of Charpy upper-shelf energy is evaluated from: CvUSE = CvUSE~u) x [1 - D/100] (Equation 16) for base metals: D = (100 Cu + 9) (f + fs) 0-2 3 6s for weld metals: D = (100 Cu + 14) (f + fs) 0 "2 36 8 the upper bound: D = 42.39 (f + fs)°-15°2 where CvUSE(u) = Charpy upper-shelf energy of the material in the preservice 2 or unirradiated condition in ft-lb, Cu = the copper content (weight percent) for the subject material, f = the increment of best-estimate total neutron fluence (in units of 1019 n/cm 2, E > 1 MeV), at the clad-base metal inter face on the inside surface of the vessel, accumulated during subsequent plant operation after the annealing operation, and fs= the "shelf recovery fluence," evaluated from Equation 15. For "credible" surveillance data, the values of "9" and "14" in Equations 15 and 16 are replaced by val ues that are based on the surveillance results. 3.2.2 Surveillance Method For the surveillance method, the reembrittlement trend is determined from the surveillance results of a program that conforms to the intent of Appendix H of 10 CFR Part 50, once the surveillance program and results from the program have met the