Document: NRC Regulatory Guide
Document ID: ceaeb6d7-d85a-46d3-a1b6-70059a498965
Document Type: regulatory_guide
Title: 12/2001 (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0131/ML013100014.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.78
CFR Part: 
CFR Title: 

Content:
one container unless the failure of that container could lead to successive failures), or (3) the largest container stored onsite (normally the total release from this container unless the containers are interconnected in such a manner that a single failure could cause a release from several containers). A maximum concentration-duration accident is one that results in a long-term, low- leakage-rate release. The majority of onsite chlorine releases experienced to date have been of this type, involving leakage from valves or fittings and resulting in a long-term release with a leakage rate from near zero to less than one pound of chlorine per second. Given warning, only breathing apparatus is necessary to protect the control room operator from this kind of release. However, because such a release might continue unabated for many hours, self-contained breathing apparatus, a tank source of air with manifold outlets, or equivalent protection capable of operation for an extended period of time should be available. For a maximum concentration-duration accident, the continuous release of hazardous chemicals from the largest safety relief valve on a stationary, mobile, or onsite source within the guidelines should be considered. 1.78-8  TABLE 2 CHEMICAL AND CONTROL ROOM DATA FOR HABITABILITY EVALUATION CHEMICAL 1. Name of hazardous chemical 2. Type of source (stationary or mobile) 3. Human detection (odor) threshold, ppm or mg/m3 (if available) 4. Toxicity limit (IDLH limit), ppm or mg/m3 5. Maximum quantity of hazardous chemical involved in incident 6. Maximum continuous release rate of hazardous chemical 7. Vapor pressure, torr, of hazardous chemical (at maximum ambient plant temperature) 8. Fraction of chemical flashed and rate of boiloff when spilling occurs 9. Distance of source from control room 10. Meteorological data CONTROL ROOM 1. Volume of the control room, including