Document: NUREG-0800
Document ID: dac334d4-585f-42f5-bde4-118e876f5d4c
Document Type: srp
Title: PIPING SYSTEMS AND COMPONENTS (Tier 1)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070660.pdf
Revision Date: 2023-06
Chapter: 14
Section ID: 14.3.3
CFR Part: 
CFR Title: 

Content:
upports provide protection of the piping; but, it is the piping itself that is needed for accident mitigation). Thus, ASME Code Class 1, 2, and 3 structural welds are included in the Tier 2 scope. The integrity of the pressure boundary in the plant will be ensured, in part, through a verification of the welding quality. This verification is performed as a part of the basic configuration ITAAC of each specific system. The basic configuration ITAAC is one of the standard ITAAC listed in Appendix D to SRP Section 14.3, is required for most systems in Tier 1. The provisions of the basic configuration check must be specified in Tier 1, and include non- destructive examination (NDE) of the as-built pressure boundary welds for the ASME Code Class 1, 2, and 3 SSCs in the design description. The acceptance criteria for the welds are the ASME Code, Section III weld examination requirements. The specific weld examination requirements for a particular ASME Code Class 1, 2, and 3 component and weld type are considered Tier 2 and 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: (1) pressure-boundary welds other than ASME Code, Section III welds, (2) structural and building steel welds, (3) electrical cable tray and conduit support welds, (4) heating, ventilation, and air-conditioning support welds, and (5) refueling cavity and spent fuel pool liner welds. 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 Class 1, 2, and 3 structural welds, the function of these other welds is needed for protection of safety-related systems, structures, and components but are not directly involved (or are redundant) in preventing an accident or event.