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:
inst tornado missiles. In addition, the number and placement of dampers must be such as to assure both flow and isolation in each inlet assuming one single active componentTaillure (see Appendix A for Information on the damper repair alternative). The location of the intakes with respect to the plant security fence should also be reviewed. (5) Bottled air supply for a limited time. In some plant designs the containment pressure is reduced below atmospheric within one hour after a DBA. This generally assures that after one hour significant radioactive material will not be released from the containment. Such a design makes it feasible to maintain the control room above atmospheric pressure by use of bottled air. Periodic pressurization tests are required to determine that the rated flow (normally about 300 to 600 cfm) is sufficient to pressurize the control room to at least 1/8-inch water gauge. The system is also required to be composed of several separate circuits, one of which is assumed to be inoperative to account for a possible single failure. At least one non-redundant, once- through filter system for pressurization as a standby for acci- dents of long duration should be provided. Compressed air bottles should be protected from tornado missiles or internally-generated missiles and should be placed so as not to cause damage to vital equipment or interference with opera- tion if they fail. 6.4-11 Rev. 2 - July 1981 4. Atmosphere Filtration Systems ETSB evaluates the iodine removal efficiency of the atmosphere filtration systems under SRP Section 6.5.1, determines the appropriate credit to be given and advises the AEB reviewer. 5. Relative Location of Source and Control Room The SAB will identify all potential sources of toxic or otherwise poten- tially hazardous gases as described in SRP Section 2.2. The SAB will provide to the AEB the findings of its toxic gas estimates for use in the control room habitability analysis. There are three basic categories: