Document: NUREG-0800
Document ID: 8c2fce42-281a-4a50-9de7-513df024f27c
Document Type: srp
Title: CONTROL ROOM HABITABILITY SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340712.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.4
CFR Part: 
CFR Title: 

Content:
e AEB reviewer ascertains from the ASB if the following system performance and availability criteria are met: a. Isolation dampers - dampers used to isolate the control zone from adjacent zones or the outside should be leaktight. This may be accomplished by using low leakage dampers or valves. The degree of leaktightness should be documented in the SAR. b. Single failure - a single failure of an active component should not result in loss of the system's functional performance. All the components of the control room emergency filter train should be con- sidered active components. See Appendix A to this SRP for criteria regarding valve or damper repair. 3. Pressurization Systems Ventilation systems that will pressurize the control room during a radia- tion emergency should meet the following requirements: a. Systems having pressurization rates of greater than or equal to 0.5 volume changes per hour should be subject to periodic verification (every 18 months) that the makeup is + 10% of design value. During 6.4-3 Rev. 2 - July 1981 plant construction or after any modification to the control room that might significantly affect its capability to maintain a positive pressure, measurements should be taken to verify that the control room is pressurized to at least 1/8-inch water gauge relative to all surrounding air spaces while applying makeup air at the design rate. b. Systems having pressurization rates of less than 0.5 and equal to or greater than 0.25 volume changes per hour should have identical testing requirements as indicated in (1), above. In addition, at the CP stage an analysis should be provided (based on the planned leaktight design features) that ensures the feasibility of maintain- ing 1/8-inch water gauge differential with the design makeup air flow rate. c. Systems having pressurization rates of less than 0.25 volume changes per hour should meet all the requirements for (2), above, except that periodic verification of control room pressurization (every 18