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:
d selected for annealing the vessel as well as the proposed instrumentation and procedures to be applied during the annealing operation. The annealing operation should not degrade the reactor or other equipment, components, and structures to such an ex tent that their ability to perform intended safety func tions can no longer be maintained. The annealing op eration must be compatible with the original design limits of the reactor system or the incompatibility should be described and justified. In such cases, addi tional design analysis may be required. The annealing method should be determined based on constraints from reactor design and accessi bility to the reactor vessel to allow insertion of equip ment and instrumentation. Selection of the method also should be based on the expected structural effects on the primary system that result from temperature gradients in the pressure vessel. The reactor vessel and adjacent equipment, com ponents, and structures should have instrumentation that permits on-line measurement of temperatures at "locations that are needed to assess the entire tempera ture profile of the reactor pressure vessel and the adja- cent equipment, components, and structures. Instru mentation should also be installed to determine the stress profiles in these items, including the effects of thermal gradients in the axial, azimuthal, and through thickness directions during all transient and steady state aspects of the annealing operation. The accuracy and reliability of the measurements should be demon strated. The stresses and strains caused by temperature gradients may be established by analysis in combina tion with on-line measurements of temperature or displacements. The annealing procedure should detail the opera tional steps to be taken during the annealing operation and should include all quality assurance measures needed to ensure an effective annealing operation. The annealing procedure should identify the controls that will be in place and