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:
, the plant-specific assessment, including explicit details and results, must be submitted to the Director of the Office of Nuclear Reactor Regulation for review and approval in the form of a license amendment at least 3 years before RTMAX–X is projected to exceed the Alternate PTS Rule screening criteria. Figure 2. Flow Diagram with Guidance for Meeting the Requirements of the Alternate PTS Rule DG-1299, Page 18 Figure 3. ASME Code, Section XI Examination and Flaw Evaluation Process and Identification of Flaws for Comparison to Alternate PTS Rule 4. Criteria Relating to Alternate Limits on Embrittlement This regulatory position describes an alternate procedure by which licensees can assess their plant-specific TWCF for cases where embrittlement criteria are not met, as allowed by Paragraph (c)(3) of 10 CFR 50.61a (i.e., the RTMAX-X limits of Table 1 of 10 CFR50.61a are not satisfied). This position fulfills the requirements in Paragraphs (d)(3) through (d)(6) of 10 CFR 50.61a, and includes calculation of a plant-specific TWCF value to provide an alternate demonstration that the limits of Table 1 of 10 CFR 50.61a are satisfied. One method to make such a demonstration is using the methods and formulae provided in Section 3.5.1, Step 4, of NUREG-1874 (Ref. 12). Satisfactory demonstration for this position includes the following steps: • Step 1. Establish the plant characterization parameters (e.g., copper, fluence). • Step 2. Estimate values of RTMAX-X using the values of the characterization parameters from Step 1 and the formulae given in Section 3.5.1 of NUREG-1874. • Step 3. Estimate the 95th percentile TWCF value, TWCF95-XX, for each of the axial weld flaw, plate flaw, circumferential weld flaw, and forging flaw populations using the RTMAX-X values from Step 2 and the formulae given in Section 3.5.1 of NUREG-1874. DG-1299, Page 19 • Step 4. Estimate the total 95th percentile TWCF, TWCF95-TOTAL, for the vessel using the formulae given in Section 3.5.1