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:
eview. 1. The reviewer determines acceptability of the containment isolation system by comparison of the system design criteria to the design requirements for an engineered safety feature. The quality standards and the seismic design classification of the containment isolation provisions, including the piping penetrating the containment, are compared to RGs 1.26 and 1.29, respectively. The reviewer also ascertains whether any single fault can prevent isolation of the containment by reviewing the containment isolation provisions for each line penetrating the containment for two isolation barriers in series and by reviewing the power sources to the valve operators. The SAR information justifying containment isolation provisions which differ from the explicit requirements of GDCs 55, 56, and 57 is reviewed. The acceptability of these containment isolation provisions is based on a comparison to the acceptance criteria of subsection II of this SRP section. The isolation valve positions are reviewed for normal and shutdown plant operating conditions, post-accident conditions, and valve operator power failure conditions as listed in the SAR. The position of an isolation valve for each condition depends on the system function. Power-operated valves in fluid systems having no post-accident safety function (nonessential systems) should close automatically. In the event of a power failure to a valve operator, the valve position should be that of greater safety, normally the post-accident position; however, special cases are considered individually for the acceptability of the prescribed valve positions. The reviewer also ascertains from the SAR whether all power-operated isolation valves have position indicators in the main control room. 6.2.4-14 Revision 3 - March 2007 2. Reviewers responsible for the structural design of the containment internal structures and piping systems, including restraints, ensure that the containment isolation provisions are protected adequately