Document: NRC Regulatory Guide
Document ID: 8291b9eb-e4a7-4806-8b5b-1deca2ff1fe2
Document Type: regulatory_guide
Title: Control Room Habitability at Light-Water Nuclear Power Reactors
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0207/ML020790125.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.196
CFR Part: 
CFR Title: 

Content:
ol room is the plant area in which actions are taken to operate the plant safely under normal conditions and to maintain the reactor in a safe condition during accident situations. The CRE encompasses the control room and may encompass the alternate shutdown panel and other rooms and areas to which personnel access may be necessary to accomplish plant control functions in the event of an accident. The structures that make up the CRE are designed to limit the inleakage of radioactive and toxic materials1 from areas external to the CRE. Control room habitability systems (CRHSs) include the CRE. CRHSs typically provide the functions of shielding, isolation, pressurization, heating, ventilation, air conditioning and filtration, monitoring, and the necessary sustenance and sanitation to ensure that the control room operators can remain in the control room and take actions to operate the plant under normal and accident conditions. The personnel protection features incorporated into the design of a 2 An example of a changed performance parameter that may require re-analysis is an increase in CRE inleakage beyond that assumed in previous CRH assessments. 3 particular plant's CRHSs depend on the nature and scope of the plant-specific challenges to maintaining CRE habitability. In the majority of the CRHS designs, isolation of the CRE atmosphere from that of adjacent areas is fundamental to ensuring a habitable control room. A licensee may use this guide for assessing CRHSs following changes to these systems or the sources that would lead to consequences to the operator. Examples of changes that may impact the existing CRH assessments and may result in a reanalysis of the licensee’s CRH are: • Changes in procedures, operation, performance,2 alignment, or function of the CRHS, • New hazardous chemicals or radioactive sources introduced onsite or in the vicinity of the plant, • Increases in hazardous chemical or radioactive source quantities, concentrations, locations,