Document: NUREG-0800
Document ID: 1c401e6c-8c2d-47df-b05f-2978939cbd15
Document Type: srp
Title: CONTROL ROOM HABITABILITY SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550069.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.4
CFR Part: 
CFR Title: 

Content:
anuary 10, 1997, applicants for and holders of combined licenses under 10 CFR Part 52 who do not reference a standard design certification, or holders of operating licenses using an alternative source term under 10 CFR 50.67, shall meet the requirements of GDC 19, except that with regard to control room access and occupancy, adequate radiation protection shall be provided to ensure that radiation exposures shall not exceed 0.05 Sv (5 rem) total effective dose equivalent (TEDE) as defined in 10 CFR 50.2 for the duration of the accident. 7. Toxic Gas Hazards. Three exposure categories are defined: protective action exposure (2 minutes or less), short-term exposure (between 2 minutes and 1 hour), and long-term exposure (1 hour or greater). Because the physiological effects can vary widely from one toxic gas to another, the following general restrictions should be used as guidance: there should be no chronic effects from exposure; acute effects, if any, should be reversible within a short period of time (several minutes) without benefit of any measures other than the use of self-contained breathing apparatus. The allowable limits should be established on the basis that the operators should be capable of carrying out their duties with a minimum of interference caused by the gas and subsequent protective measures. The limits for the three categories normally are set as follows: A. Protective action limit (2 minutes or less): Use a limit that will ensure that the operators will quickly recover after breathing apparatus is in place. In determining this limit, it should be assumed that the concentration increases linearly with time from zero to two minutes and that the limit is attained at two minutes. 6.4-8 Revision 3 - March 2007 B. Short-term limit (2 minutes to 1 hour): Use a limit that will ensure that the operators will not suffer incapacitating effects after a 1-hour exposure. C. Long-term limit (1 hour or greater): Use a limit assigned for occupational exposure