Document: NUREG-0800
Document ID: 9e12eef7-842c-43db-9170-12cf365ca8b9
Document Type: srp
Title: PIPING SYSTEMS AND COMPONENTS - INSPECTIONS, TESTS, ANALYSES,
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0706/ML070660622.pdf
Revision Date: 2023-06
Chapter: 14
Section ID: 14.3.3
CFR Part: 
CFR Title: 

Content:
e Class 1, 2, or 3 component and weld type are tabulated in Tier 2. The specific weld examination requirements are considered Tier 2 because they could change depending on future revisions to the ASME Code, Section III requirements. Other welding activities (non-ASME Code) include: i. Pressure-boundary welds other than ASME Code, Section III welds, ii. Structural and building steel welds, iii. Electrical cable tray and conduit support welds, iv. Heating, ventilation, and air-conditioning support welds, and v. Refueling cavity and spent fuel pool liner welds. March 2007 14.3.3-8 These other types of welding are included in the Tier 2 scope. Tier 2 describes the applicable codes and standards for the other types of welding and the weld acceptance criteria. Similar to the ASME Code Classes 1, 2, and 3 structural welds, these other welds are needed for protection of safety-related SSCs but do not directly (or are redundant) prevent accidents or events. Accordingly, these other types of welding were deemed inappropriate for Tier 1 scope. C. Hydrostatic Test. The integrity of the pressure boundary is required to be maintained because it is directly involved in preventing or mitigating an accident or event under the defense-in-depth principle. The pressure boundary integrity is also ensured, in part, through a hydrostatic test verifying the leak-tightness of the ASME Code piping systems. A hydrostatic test is generally specified by the ASME Code, Section III, for ASME Code Class 1, 2, and 3 SSCs to verify whether pressure integrity is maintained in the process of fabricating the overall piping system, including any welding and bolting requirements. However, the ASME piping stress report in the generic piping ITAAC does not include the results of hydrostatic tests; therefore, the standard hydrostatic test ITAAC in SRP Section 14.3, Appendix D, should be specified in each system ITAAC with ASME Code Class 1, 2, or 3 SSCs. The hydrostatic test ITAAC also may be specified in