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
CFR Part: 
CFR Title: 

Content:
inment isolation valves should require deliberate operator action. In addition, ganged reopening of containment isolation valves is not acceptable. Reopening of isolation valves must be performed on a valve-by-valve basis, or on a line-by-line basis, provided that electrical independence and other single-failure criterion continue to be satisfied. Administrative provisions to close all isolation valves manually before resetting the isolation signals is not an acceptable method of meeting this design requirement. t. In meeting the requirements of 10 CFR 50.34(f)(2)(xv) regarding purging, the regulatory guidance contained in BTP CSB 6-4, "Containment Purging During Normal Plant Operations," should be used to establish compliance with this regulation.60 u. Regulatory Guide 1.155, "Station Blackout," Regulatory Position C.3.2.7, provides guidance for meeting the requirements of the station blackout rule, 10 CFR 50.63(a)(2), with respect to containment isolation valves and valve position indication.61 v. Appendix K to 10 CFR Part 50 provides guidance for the determination of the extent of fuel failure (source term) used in the radiological calculations.62 Technical Rationale The technical rationale for application of these acceptance criteria to reviewing the containment isolation system is discussed in the following paragraphs:63 1. Compliance with General Design Criterion 1 (GDC 1), "Quality Standards and Records," requires that structures, systems, and components important to safety be designed, fabricated, erected, and tested to quality standards commensurate with the safety functions to be performed. This SRP section defines appropriate reliability and performance standards for the design of the containment isolation system. These standards reflect the importance of forming a barrier that is essentially leaktight and that will prevent the release of fission products in the event of an accident. Regulatory Guide 1.26 specifies quality standards that are applicable to