Document: 10 CFR Part 50
Document ID: cfc9c7b0-bbcd-4774-97ce-900cbc760408
Document Type: cfr
Title: Codes and standards.
Source: 10 CFR Part 50
Source URL: https://www.ecfr.gov/current/title-10/part-50/section-50.55a
Revision Date: 
Chapter: 
Section ID: 50.55a
CFR Part: 50
CFR Title: 10

Content:
ddenda incorporated by reference in paragraph (a)(1)(ii) of this section, insulation must be removed from 17-4 PH or 410 stainless steel studs or bolts aged at a temperature below 1100 °F or having a Rockwell Method C hardness value above 30, and from A-286 stainless steel studs or bolts preloaded to 100,000 pounds per square inch or higher. ( xxviii ) Section XI condition: Analysis of flaws. Licensees using ASME BPV Code, Section XI, Appendix A, must use the following conditions when implementing Equation (2) in A-4300(b)(1): For R < 0, ΔK I depends on the crack depth (a), and the flow stress (σ f ). The flow stress is defined by σ f = 1/2(σ ys + σ ult ), where σ ys is the yield strength and σ ult is the ultimate tensilestrength in units ksi (MPa) and (a) is in units in. (mm). For −2 ≤ R ≤ 0 and K max − K min ≤ 0.8 × 1.12 σ f √(πa), S = 1 and ΔK I = K max . For R < −2 and K max − K min ≤ 0.8 × 1.12 σ f √(πa), S = 1 and ΔK I = (1 − R) K max /3. For R < 0 and K max − K min > 0.8 × 1.12σ f √(πa), S = 1 and ΔK I = K max −K min . ( xxix ) Section XI condition: Nonmandatory Appendix R. ( A ) Nonmandatory Appendix R, “Risk-Informed Inspection Requirements for Piping Supplement 1—Risk-Informed Selection Process—Method A,” of Section XI, 2005 Addenda through the latest edition and addenda incorporated by reference in paragraph (a)(1)(ii) of this section, may not be implemented without prior NRC authorization of the proposed alternative in accordance with paragraph (z) of this section. ( B ) Nonmandatory Appendix R, “Risk-Informed Inspection Requirements for Piping, Supplement 2—Risk-Informed Selection Process—Method B” of Section XI, 2005 Addenda through the 2015 Edition, may not be implemented without prior NRC authorization of the proposed alternative in accordance with paragraph (z) of this section. ( C ) Nonmandatory Appendix R, “Risk-Informed Inspection Requirements for Piping, Supplement