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:
me chemistry factor (in OF) used for the pre-anneal operating period, based on the nickel and copper content of the material or the results of the "credible" surveillance program, f f the increment of best-estimate neutron fluence (in units of 1019 n/cm2, E > 1 MeV), at the clad-base metal interface on the inside surface of the vessel, accumulated during plant operation subsequent to the annealing operation, and ft= the "transition recovery fluence," evaluated from Equation 10. M - 2 la_ + ao2 (Equation 13) where rately model the various Charpy uppershelf energy de crease curves. Using the equations in Reference 21: CvUSE = CvUSE(u) x [I - D/100] (Equation 14) for base metals: D = (100 Cu + 9) (00.2368 for weld metals: D = (100 Cu + 14) (f0.2368 the upper bound: D = 42.39 (f)0.1502 where CvUSE = Charpy upper-shelf energy of the material in the irradiated condition (before annealing) 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), Cu = copper content (weight-percent) for the subject material, and f = the best-estimate total neutron fluence (in units of 1019 n/cm 2, E > I MeV), at the clad-base metal interface on the inside surface of the vessel. The value of D is the lesser of that from the appro priate equation for the material type and that from the upper bound equation. For "credible" surveillance data, guidance is given in Revision 2 of Regulatory Guide 1.99 (Ref. 21) for determining percent decrease in Charpy upper-shelf energy based on the surveillance results. For reembrittlement, the lateral shift is accom plished by determining the "shelf recovery fluence," fs, from: 01 = standard deviation of RTNDT(U) in OF, = 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