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:
om the results of the tests from the samples. 3.1.2.1 Acceptability of Removing Material from the Vessel. The acceptability of the method used for removing samples from the vessel beltline is based on local and global considerations, both of which should be addressed in the assurance program. The global considerations concern the impact on overall vessel integrity of the depression, hole, or surface dis continuity remaining after removal of the sample, and they are addressed through analysis. The local consid erations concern thermal and mechanical effects and surface quality effects on the surrounding material re maining after removal of the samples. The sample removal process should be described in the assurance program, including a description of the measures to ensure the identification and docu mentation of the orientation of the sample relative to the vessel. The removal of samples from the vessel beltline will result in a depression or other surface discontinuity in the vessel wall. As required in the thermal annealing rule (10 CFR 50.66), it must be demonstrated that the resulting depressions satisfy the stress limits of the applicable portions of the ASME Code Section III, re gardless of the applicable section of the Code for the vessel design. The analyses used to demonstrate com- pliance with the applicable stress limits of Section III of the ASME Code must include consideration of the ef fects of fatigue and corrosion on the exposed base metal following removal of the samples, and the analy ses should consider any thermal and mechanical ef fects on the surface and near-surface material remain ing after removal of the sample. The assurance program should describe the meth od proposed to characterize the depression remaining after sample removal to ensure that the condition of the remaining material is bounded by the assumptions in the analysis and is acceptable. Any proposed re pairs, including weld repair, should be described in the Thermal Annealing