Document: NUREG-0800
Document ID: 632e6c59-03bd-4648-b0b3-e8b2efd6fa04
Document Type: srp
Title: CONTAINMENT ISOLATION SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0703/ML070380197.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.4
CFR Part: 
CFR Title: 

Content:
should be the following technical specifications: containment purge or vent valves that do not 6.2.4-15 Revision 3 - March 2007 satisfy BTP 6-4 operability criteria must be sealed closed as defined in subsection II.6 (Acceptance Criteria) of this SRP section and verified sealed closed at least every 31 days during all operational conditions except cold shutdown and refueling; purging or venting time should be minimized consistently with as low as reasonably achieved principles for occupational exposure; and containment purge or vent valves with resilient seals must be subjected to leakage-testing and periodic resilient seal replacement. 7. The reviewer determines the acceptability of the use of closed systems inside containment as isolation barriers by comparing the system designs to the Acceptance Criteria of subsection II of this SRP section. 8. Isolation valve closure times are reviewed. In general, valve closure times should be less than one minute regardless of valve size. (See the Acceptance Criteria for valve closure times in subsection II of this SRP section). Valves in lines that provide direct paths to the environs (e.g., the containment purge and ventilation system lines and main steam lines for direct cycle plants) may have to close in times much shorter than one minute. Closure times for these valves may be dictated by radiological dose analyses or emergency core cooling system performance considerations. The reviewer requests reviews of analyses justifying closure times for these valves as necessary. 9. The reviewer evaluates the design features of the purging/venting system for minimizing purging time and verifies whether there is a high degree of assurance that the purge system will isolate reliably under accident conditions. 10. The reviewer verifies whether appropriate containment integrity is maintained in SBO by the capability, independent of the preferred and blacked-out unit's onsite emergency AC power supplies, for valve position indication