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:
mens of the approved plan. Preparation and use of these various specimen types is described in Section 3.14. 3.1.3 Computational Method The computational method uses generic equations (Equations I and 2) to determine the percent recovery of Charpy upper-shelf energy (USE) and ARTNDT re spectively. Alternative computational methods may be used if appropriate justification is provided. When de termining the projected percent recovery for the an nealing plan, the proposed lower-bound annealing 1.162-10 time and temperature are used in Equations 1 and 2. However, when computing the post-anneal percent recovery, the actual annealing time and the lower bound of the range of actual annealing temperatures determined from the instrumentation (see Section 2.1 of this guide) should be used. RUSE = {[1-0.586 exp(-ta/15. 9)] x [0.570AUSEi + (0.120Ta-10 4) Cu+0.0389Ta-17.6]} x (100/AUSEji (Equation 1) where RUSE = percent recovery of USE from annealing, AUSEi = (mean USE unirradiated - mean USE after irradiation), ta = time at annealing temperature in hours, Ta = annealing temperature in °F, Cu = copper content of material in weight-percent. R= = [0.5 + 0.5 tanh((aTa - a2)/95.7}1]* 100 (Equation 2) where Rt = percent recovery of transition temperature from annealing, Sal = 1 + 0.0151 ln(ta) 0.424Cu( 3.28 - 0.00306Ta) a2 = 0.584(Ti + 637), for Ta k 800OF or a2 = 0.584T1 - 15.51n(O) + 833 for Ta < 750 0F where TC Cu. flux rate, n/(cm2-s), temperature of irradiation. copper content of material in weight percent with maximum value of 0.3%. The current Rt equation is not accurate between annealing temperatures of 750 and 800 0 F. Until a complete equation is developed an extension of the ef fect of the flux term (a2) is assumed to a temperature of 775*F. Between 775 and 800°F, a linear interpola tion between Equation 2 evaluated at 775 °F with the flux term and Equation 2 evaluated at 8000 without the flux term should be made. Since plant operational characteristics do not re sult