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:
is 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 described in Step 2(d)(ii) do not explain or rationalize the cause of the statistical tests not being satisfied, adjustment of the ETC predictions based on plant specific data should be considered. Three situations exist for which a specific procedure may be used, as follows: 1. Mean Test Failure: One procedure for adjusting ETC predictions to account for a failure of the mean test is illustrated on the left side of Figure 1. This procedure is as follows: a. Calculate the value ADJ as follows: max r r ADJ mean− = DG-1299, Page 13 b. Adjust the prediction of Equation (5) as follows: ADJ CRP MD T ADJ + + = Δ ) ( 30 c. Use the value ΔT30(ADJ) in place of the predicted ΔT30 in all calculations required by the Alternate PTS Rule for the materials that do not satisfy the mean statistical test. 2. Slope Test Failure: One procedure for adjusting ETC predictions to account for a failure of the slope test is to adjust the ETC predictions (Eq. (5)) from the Alternate PTS Rule based on the greater increase of embrittlement with fluence suggested by the plant-specific data. The specific procedure used should be technically justified and documented. 3. Outlier Test Failure (Not Satisfied at Low Fluence): The right side of Figure 1 illustrates a situation where a ΔT30 value measured at low fluence is responsible for not satisfying the outlier test. Such a situation is not considered relevant to a PTS evaluation, and may therefore be ignored, provided that both of the following conditions are satisfied: a. The fluence of the datum that caused the outlier test failure (ϕtLOW) is less 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