Document: NRC Regulatory Guide
Document ID: 4b34bbdf-f837-4227-9a0d-3f0ad3778b30
Document Type: regulatory_guide
Title: Protection of Nuclear Power Plant Control Room Operators Against an Accidental Chlorine Release (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1229/ML12298A134.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.95
CFR Part: 
CFR Title: 

Content:
ease, exhaust fans should be stopped and/or isolated from the control room ven- tilation zone by low-leakage dampers or valves). (3) A control room exit leading directly to the outside of the building should have two low-leakage doors in series. c. The use of full-face self-contained pressure- demand-type breathing apparatus (or the equivalent) and the use of protective clothing should be con- sidered in the development of a chlorine release emergency plan. Because calculations indicate that chlorine concentrations may increase rapidly, emergency plan provisions and rehearsal of these provisions are necessary to ensure donning of breathing apparatus on detection of high chlorine I 4 1.95-4 concentrations. Storage provisions for breathing ap- paratus and procedures for their use should be such that operators can begin using the apparatus within two minutes after an alarm. Adequate air capacity for the breathing apparatus (at least six hours) should be readily available onsite to ensure that sufficient time is available to transport additional bottled air from offsite locations. This offsite supply should be capable of delivering several hundred hours of bot- tled air to members of the emergency crew. A minimum emergency crew should consist of those personnel required to maintain the plant in a safe condition, including orderly shutdown or scram of the reactor. As a guideline, a minimum of five units of breathing apparatus should be provided for the emergency crew. d. The air supply apparatus should meet the single failure criterion and be designated Seismic Category I. (In the case of self-contained breathing apparatus, the single failure criterion may be met by supplying one extra unit for every three units required.) The isolation system components should be of a quality that ensures high reliability and availability. One method to meet these goals is to provide a system that meets the requirements of IEEE-279, "Criteria for Protection Systems for Nuclear Power