Document: NRC Regulatory Guide
Document ID: 3df13dae-14ee-4f25-95b4-1cedf617ae15
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:
ess than 10 percent of the fluence at which the PTS evaluation is being performed (ϕtEVAL), and b. After elimination of the datum measured at (ϕtLOW), the entry conditions for the surveillance tests are still met (i.e., at least three datum measured at three different fluence values remain) and all three statistical tests are satisfied with the reduced data set. Other approaches to assessment of surveillance data where all surveillance measurements are bounded are subject to review and approval by the NRC. DG-1299, Page 14 Figure 1. Specific Procedures to Address Unsatisfactory Mean Statistical Test (left) or Low Fluence Outlier Statistical Test (right) 3. Criteria Relating to ISI Data and NDE Requirements Figure 2 illustrates the procedure in 50.61a for examination and flaw detection requirements. Compliance with Tables 2 and 3 of 10 CFR 50.61a demonstrates that the flaw distribution in the RPV is adequately represented by the flaw distribution assumed in the PFM calculations that established the technical basis for the RTMAX-X limits in Table 1 of 10 CFR 50.61a. The steps in the flowchart of Figure 2 are as follows: Step A: All plant-specific recordable flaw data (see Figure 3) should be collected for the inner three-eighths of the wall thickness (3/8t) for the base material and weld metal examination volumes within the RPV beltline region using procedures, equipment and personnel, as required in ASME Code, Section XI (Ref. 7), Mandatory Appendix VIII, Supplements 4 and 6, using UT volumetric examinations. • Note: Any flaws that are detected within the ultrasonic transducer scan paths, but are located outside of the required ASME Code, Section XI, examination volume, should also be included in the flaw table evaluation. Step B: The plant-specific flaw data from Step A should be evaluated for axial flaw surface connection. Any flaws with a through-wall extent greater than or equal to 0.075 inch, axially oriented and located at the clad-to-base metal interface,