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:
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 applicant commits to their use during severe radiation releases. However, even though protective clothing is used, the calculated unprotected skin dose is not to exceed 75 rem. The skin and thyroid dose levels are to be used only for judging the acceptability of the design provisions for protecting control room operators under postulated design basis accident conditions. They are not to be interpreted as accept- able emergency doses. The dose levels quoted here are derived for use in the controlled plant environment and should not be confused with the conservative dose computation assumptions used in evaluating exposures to the general pub- lic for the purooses of comparison with the guideline values of 10 CFR Part 100. 6.4-5 Rev. 2 - July 1981 The protective action limit is used to determine the acceptability of emergency zone protection provisions during the time personnel are in the process of fitting themselves with self-contained breathing apparatus. The other limits are used to determine whether the concentrations with breathing apparatus in place are applicable. They are also used in those cases where the toxic levels are such that emergency zone isolation with- out use of protective gear is sufficient. Self-contained breathing apparatus for the control room personnel (at least 5 individuals) should be on hand. A six-hour onsite bottled air supply'should be available with unlimited offsite replenishment capability from nearby location(s). As an example of appropriate limits, the following are the three levels for chlorine gas: protective action: 15 ppm by volume 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