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:
me short-term: 4 ppm by volume long-term: 1 ppm by volume Regulatory Guide 1.78 (Ref. 7) provides a partial list for protective action levels for other toxic gases. III. REVIEW PROCEDURES The reviewer selects and emphasizes aspects of the areas covered by this review plan as appropriate for a particular case. The.judgment on areas to be given attention and emphasis in the review is based on an inspection of the material presented to see whether it is similar to that recently reviewed for other plants and whether items of special safety significance are involved. 1. Control Room Emergency Zone The reviewer verifies that the control room emergency zone includes the areas identified in Subsection 11.1 of this SRP section. The emergency zone should be limited to those spaces requiring operator occupancy. Spaces such as battery rooms, cable spreading rooms, or other spaces not requiring continuous or frequent occupancy after a design basis accident (DBA) generally should be excluded from the emergency zone. Inclusion of these spaces may increase the probability of smoke or hazardous gases entering the emergency zone. They may also increase the possibility of infiltration into the emergency zone, thus decreasing the effectiveness of the ventilation system in excluding contamination.. It is advantageous to have the emergency zone located on one floor, with the areas included in the zone being contiguous. 2. Control Room Personnel Capacity A control room designed with complete isolation capability from the out- side air to provide radiation and toxic gas protection is reviewed to determine if the buildup of carbpn dioxide could present a problem. The air inside a 100,000 cubic foot control room would support five persons for at least six days. Thus, C02 buildup in an isolated emergency zone is not normally considered a limiting problem. 6.4-6 Rev. 2 - July 1981 3. Ventilation System Layout and Functional Design The reviewer evaluates the control room ventilation system in