Document: NUREG-0800
Document ID: 6c5a07e2-91cf-49ae-a450-62551ed6bcef
Document Type: srp
Title: CONTAINMENT ISOLATION SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340703.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.4
CFR Part: 
CFR Title: 

Content:
e design and use of containment purge systems which may be used during the normal plant operating modes (i.e., startup, power operation, hot standby and hot shut- down) is provided in Branch Technical Position CSB 6-4 (Ref. 13). For plants under review for operating licenses or plants for which the Safety Evaluation Report for.construction permit application was issued prior to July 1, 1975, the methods described in Section B, Items B.L.a, b, d, e, g, f, and g, B.2 through B.4, and B.5.b, c, and d of Branch Technical Posi- tion CSB 6-4 should be implemented. For these plants, BTP Items B.1.c and B.5.a, regarding the size of the purge system used during normal plant operation and the justification by acceptable dose consequence-analysis, may be waived if the applicant commits to limit the use of the purge sys- tem to less than 90 hours per year while the plant is in the startup, power, hot standby and hot shutdown modes of operations. This commitment should be incorporated into the Technical Specifications used in the operation of the plant. 6.2.4-6 Rev. 2 - July 1981 Item II.E.4.2 of NUREG-0737 and NUREG-0718 requires that containment purge valves that do not satisfy the operability criteria set forth in Branch Technical Position CSB 6-4 or the Staff Interim Position of October 23, 1979 must be sealed closed as defined in SRP Section 6.2.4, Item II.3.f during operational conditions 1, 2, 3 and 4. Furthermore, these valves must be verified to be closed at least every 31 days. (A copy of the Staff Interim Position appears as Attachment 1 to Item II.E.4.2 in NUREG-0737.) o. The use of a closed system inside containment as one of the isolation barriers will be acceptable if the design of the closed system satisfies the following requirements: 1. The system does not communicate with either the reactor coolant sys- tem or the containment atmosphere. 2. The system is protected against missiles and pipe whip. 3. The system is designated seismic Category I. 4. The system is