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:
his guide) to form new, full-size specimens with the insert material being the only material from the original surveillance specimen. These reconstituted specimens, and any untested specimens from the original speci men complement, should be annealed at time and temperature conditions that are equal to or are bounded by the actual vessel annealing conditions. This method may be applied to broken specimens from a single capsule or multiple capsules from the sur veillance program. Specimens from at least two cap sules should be used, with the fluences of the two cap sules spanning the peak fluence of the reactor pressure vessel beltline; this ensures that an interpolation of the annealing recovery is possible. If broken specimens from only a single capsule are used, the specific surveil lance capsule chosen should be the one for which the fluence most closely matches the peak fluence of the reactor pressure vessel beltline. As an alternative, materials test reactor (MTR) ir radiations of the vessel-specific limiting material may be used as a method for determining percent recovery on a material-specific basis (see Section 3.3 of this guide). Methods for testing the specimens and using the resultant data are discussed in Sections 3.1.5 and 3.1.6 of this guide. The assurance program should describe the plans for using the surveillance results, including a descrip tion of the procedure for generating post-anneal prop erties (e.g., reconstituted specimens or whole pre viously untested specimens) and the method for using the surveillance measurements of percent recovery to evaluate the percent recovery for the vessel material. 3.1.2 Irradiated Vessel Material Method An alternative method for determining the per cent recovery uses the results of a verification test pro gram employing materials removed from the beltline region of the reactor vessel. For this method, the sam ples removed from the vessel are used to evaluate the as-irradiated or pre-anneal condition of the