Document: NUREG-0800
Document ID: 1c401e6c-8c2d-47df-b05f-2978939cbd15
Document Type: srp
Title: CONTROL ROOM HABITABILITY SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550069.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.4
CFR Part: 
CFR Title: 

Content:
lish appropriate parameters to be used in the control room dose calculations. The control room ventilation system design and performance is evaluated in accordance with SRP Section 9.4.1. The reviewer should use Regulatory Guide 1.52 and, for new applications, ASME Code AG-1 including the AG-1a-92 Addenda to evaluate the system. The procedures are as follows: A. The type of system proposed is determined. The following types of protection provisions are currently being employed for boiling water reactor (BWR) or pressurized water reactor (PWR) plants: 6.4-11 Revision 3 - March 2007 i. Zone isolation, with the incoming air filtered and a positive pressure maintained by the ventilation system fans. This arrangement is often provided for BWRs having high stacks. Airflow rates are between 190 and 1900 L/s (400 and 4000 cfm). ii. Zone isolation, with filtered recirculated air. This arrangement is often provided for BWRs and PWRs with roof vents. Recirculation rates range from 950 to 14,200 L/s (2000 to 30,000 cfm). iii. Zone isolation, with filtered recirculated air, and with a positive pressure maintained in the zone. This arrangement is essentially the same as that in (2), with the addition of the positive pressure provision. iv. Dual air inlets for the emergency zone. In this arrangement, two widely spaced inlets are located outboard, on opposite sides of potential toxic and radioactive gas sources. The arrangement ensures at least one inlet being free of contamination, except under extreme no-wind conditions. It can be used in all types of plants. Makeup air supplied from the contamination-free inlet provides a positive pressure in the emergency zone and thus minimizes infiltration. v. Bottled air supply for a limited time. In this arrangement, a flow rate of 190 to 290 L/s (400 to 600 cfm) is provided from compressed air containers for about 1 hour to assist in preventing inleakage. It is used in systems having containments whose internal atmospheric pressure becomes