Document: NUREG-0800
Document ID: c23d52ec-d83f-4468-b35e-e8c97fdf2f09
Document Type: srp
Title: CONTAINMENT ISOLATION SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070461.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.4
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CFR Title: 

Content:
nt must demonstrate that the radiological consequences following a loss-of-coolant accident would be within 10 CFR Part 100 guideline values. In summary, the acceptability of a specific line size is a function of the site meteorology, containment design, and radiological source term for the reactor type, e.g., BWR, PWR, or HTGR. B. BRANCH TECHNICAL POSITION The systems used to purge the containment for the reactor operational modes of power operation, startup, hot standby and hot shutdown, i.e., the on-line purge system, should be independent of the purge system used for the reactor operational modes of cold shutdown and refueling. 1. The on-line purge system should be designed in accordance with the following criteria: a. General Design Criterion 54 requires that the reliability and performance capabilities of containment isolation valves reflect the importance of safety of isolating the systems penetrating the containment boundary. Therefore, the performance and reliability of the purge system isolation valves should be consistent with the operability assurance program outlinedcontained in Branch 132 Technical Position MEB-2, "Pump and Valve Operability Assurance Program." (Also see SRP Section 3.10.)SRP Section 3.10. The design basis for the valves 133 and actuators should include the buildup of containment pressure for the LOCA break spectrum, and the supply line and exhaust line flows as a function of time up to and during valve closure. b. The number of supply and exhaust lines that may be used should be limited to one supply line and one exhaust line, to improve the reliability of the isolation function as required by General Design Criterion 54, and to facilitate compliance 6.2.4-23 DRAFT Rev. 3 - April 1996 with the requirements of Appendix K to 10 CFR Part 50 regarding the containment pressure used in the evaluation of the emergency core cooling system effectiveness and 10 CFR Part 100 regarding offsite radiological consequences. c. The size of the lines