Document: NRC Regulatory Guide
Document ID: e1a28538-35cc-4fc2-ab12-2e1d95830205
Document Type: regulatory_guide
Title: Acceptability of ASME Code, Section XI, Division 2, Requirements for RIM Programs for NPPs, for Non-LWRs
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2112/ML21120A185.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.246
CFR Part: 
CFR Title: 

Content:
he NRC staff noted that the tables did not identify stress relaxation cracking (sometimes referred to as reheat cracking) as a degradation mechanism. Stress relaxation cracking should be considered in addition to the degradation mechanisms in Mandatory Appendix VII degradation mechanism tables. DG-1383, Page 12 Basis for Regulatory Guidance Position 14 RIM-4.2.3 calls for liquid leak tests to be conducted in accordance with ASME Code, Section V, “Nondestructive Examination” (Ref. 17), Article 10, Mandatory Appendix IV, “Helium Mass Spectrometer Test,” or Mandatory Appendix VI, “Pressure Change Test.” A helium mass spectrometer test is not a liquid test and would not be consistent with the remaining paragraphs in RIM-4.2.3. Also, ASME Code, Section V, Article 10, does not provide instructions for conducting a pressure test and performing a visual test to identify leakage. The NRC staff believes that a pressure drop test or a pressure test in conjunction with a visual test are appropriate means for liquid leak tests. RIM-4.2.3 establishes a hold time of 10 minutes for components not required for normal plant operation. The NRC staff views this as insufficient for ensuring small leaks are detected on insulated components. It is the NRC staff’s position that the hold time should be 4 hours for components that are insulated. Basis for Regulatory Guidance Position 15 The 2019 Edition of ASME Code, Section XI, Division 2, included a few inadvertent errors in paragraphs VII-1.4.2.3 and VII-3.4.2.3 and in article references in nonmandatory Appendix A. These are inconsequential errors. These items have been identified to the applicable ASME Code committees to address either by errata or by changes to the code. Paragraphs VII-1.4.2.3 and VII-3.4.2.3 for linear flaws in Category D, for full penetration welds of nozzles in vessels refers to figures IWC-2500-1 and IWC-2500-2. These figures relate to vessel welds, not nozzle welds in vessels. Figures IWB-2500-7(a)