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:
provisions are as follows: 6.4-4 Rev. 2 - July 1981 whole body gamma: 5 rem thyroid: 30 rem beta skin dose: 30 rem* In accordance with GOC 19 (Ref. 3), these doses to an individual in the control room should not be exceeded for any postulated design basis accident. The whole body gamma dose consists of contributions from airborne radioactivity inside and outside the control room, as well as direct shine from all radiation sources. 7. Toxic Gas Hazards Three exposure categories are defined: protective action exposure (2 minutes or less), short-term exposure (between 2 minutes and I hour), and long-term exposure (I 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 interfer- ence 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 assure that the operators will quickly recover after breathing appa- ratus 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. b. Short-term limit (2 minutes to 1 hour): use a limit that will assure that the operators will not suffer incapacitating effects after a 1-hour exposure. c. Long-term limit (I hour or greater): use a limit assigned for occupational exposure (40-hour week). "Credit for the beta radiation shielding afforded by special protective clothing and eye protection is allowed if the