Document: NRC Regulatory Guide
Document ID: 0d99822b-1af0-41be-a088-75b961301b4f
Document Type: regulatory_guide
Title: Regulatory Guidance on the Alternate Pressurized Thermal Shock Rule + HISTORY - HISTORY 03/2015 – DG-1299 , Proposed Revision 0
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1405/ML14056A011.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.230
CFR Part: 
CFR Title: 

Content:
ns of Equation (5) are very sensitive to the value of the input variables, particularly Cu content, fluence, temperature, and Ni content. If a sensitivity analysis reveals that small variations of the values input to Equation (5) explain the cause of not satisfying the statistical tests, this might indicate that more refined information concerning input values (e.g., additional measurements) are necessary, and may form the basis for proposing ΔT30 and RTMAX-X values considering the plant-specific surveillance data. Specific limits are not provided; these should be justified on a case-specific basis. • Notch orientation: The T30 values for plate and forging materials are sensitive to the orientation of the notch in the CVN specimens relative to the primary working directions of the plate or forging materials. Differences in notch orientation between the unirradiated T30 values and the T30 values for all of the irradiated specimens could help to explain why the mean test is not satisfied. Similarly, differences in notch orientations between the unirradiated T30 values and the T30 values for the irradiated specimens in a single capsule could help to explain why the outlier is not satisfied. In these situations, the outcome of a records search or metallurgical investigation of the tested specimens may provide part of the basis for proposing ΔT30 and RTMAX-X values considering the plant-specific surveillance data. • Comparative trends analysis: In addition to CVN specimens, surveillance capsules also contain tensile specimens. Like ΔT30, the increase in yield strength with irradiation (ΔYS) also follows predictable trends. If ΔYS data for a particular material that failed the statistical tests follow the trends exhibited by ΔYS data for a similar composition, this information may form part of the basis for proposing ΔT30 and RTMAX-X values considering the plant-specific surveillance data. iii. Specific Procedures: In the event that the evaluation of factors