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:
pensatory measures to be taken in the event of an intentional or unintentional entry into Condition B. If the control room boundary is inoperable in MODE 1, 2, 3, or 4, the CREFS trains cannot perform their intended functions. Actions must be taken to restore an OPERABLE control room boundary within 24 hours14 days. During the period that the control room boundary is inoperable, appropriate compensatory measures (consistent with the intent of GDC 19) should be utilized to protect control room operators from potential hazards such as radioactive contamination, toxic chemicals, smoke, temperature and relative humidity, and physical security. Preplanned measures should be available to address these concerns for intentional and unintentional entry into the condition. The 24 hour14 day Completion Time is reasonable based on the low probability of a DBA occurring during this time period, and the use of compensatory measures. The 24 hour14 day Completion time is a typically reasonable time to diagnose, plan and possibly repair, and test most problems with the control room boundary. C.1, C.2 and C.3 - REVIEWER'S NOTE - Condition C is to be supported by a licensee written program and procedures describing compensatory measures to be taken in the event of an intentional or unintentional entry into Condition C. With unfiltered inleakage greater than that assumed in the design analysis, the control room envelope is inoperable. However, rather than requiring a ACTIONS (continued) CREFS 3.7.10 A-10 plant shut down, compensatory measures adequately protect control room operators. This ACTION also requires a thorough and prompt action plan to restore the control room envelope to OPERABLE status. CD.1 and CD.2 In MODE 1, 2, 3, or 4, if the inoperable CREFS train or control room boundary cannot be restored to OPERABLE status within the required Completion Time, the unit must be placed in a MODE that minimizes accident risk. To achieve this status, the unit must be placed in at least