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:
a statistical slope test. Licensees who utilize this guidance should perform the statistical slope test as follows: i. Using the method of least squares, estimate the slope of the ETC model residuals (i.e., the r values, from Eq. (8)) plotted as a function of the base 10 logarithm of neutron fluence for the specific data set. Also estimate the standard-error of the estimated value of slope, se(m). ii. Estimate the T-statistic for m as follows: se(m) m TSURV = (11) DG-1299, Page 9 iii. Determine the critical value of T (TCRIT) from the rightmost column in Table 3. For surveillance data sets with greater than 15 data points, the TMAX value should be calculated using Student’s T distribution with a significance level (α) of 1 percent for a one-tailed test. iv. If TSURV exceeds TCRIT, then the slope test is not satisfied; in this case proceed to Step 2(d). If TSURV is less than or equal to TCRIT then the slope test is satisfied; in this case proceed to Step 2(c). Table 3. α = 1% Student’s-T Values. Number of ΔT30 Values, n n-2 One-Tailed TCRIT (1%, n-2) 3 1 31.82 4 2 6.96 5 3 4.54 6 4 3.75 7 5 3.36 8 6 3.14 9 7 3.00 10 8 2.90 11 9 2.82 12 10 2.76 13 11 2.72 14 12 2.68 15 13 2.65 (c) Outlier Test Paragraph (f)(6)(iv) of 10 CFR 50.61a requires that the licensee perform a statistical outlier test. Licensees who utilize this guidance should perform the statistical outlier test as follows: i. Estimate the normalized residual, r, for each or the n observations in the ΔT30 dataset: σ r r* = (12) where r is defined using Equation (8) and σ is from Table 2. ii. Find the largest and second largest r* values; designate these r*1 and r*2, respectively. Find the limit values of rLIMIT(1) and rLIMIT(2) corresponding to the dataset size n in DG-1299, Page 10 iii. Table 4. iv. If r*1 ≤ rLIMIT(1) and r*2 ≤ rLIMIT(2) then the dataset satisfies the outlier test; otherwise it does not. In either case proceed to Step 2(d). DG-1299, Page 11 Table 4. α = 1% Threshold Value for