Document: NUREG-0800
Document ID: 50c5f9b6-d85c-4012-a8e9-48eaaafff93e
Document Type: srp
Title: CONTROL ROOM AREA VENTILATION SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550045.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.4.1
CFR Part: 
CFR Title: 

Content:
at could result from equipment failures or from events and conditions outside the nuclear power unit. The function of the CRAVS is to provide a suitable and controlled environment for the control room during normal operation, anticipated operational occurrences, and during and after postulated accidents, including loss of offsite power. To ensure performance of these functions under accident conditions, portions of the CRAVS must be designed to accommodate accident environmental effects and be appropriately protected from dynamic effects associated with postulated accidents. The requirements of GDC 4 ensure that control room area systems and components important to safety (with environmental support from the CRAVS) and safety-related portions of the CRAVS are designed to address the expected environmental conditions and dynamic effects associated with the specified events and conditions for which they are required to function. GDC 4 requirements provide assurance that the CRAVS will support the functioning of systems and components important to safety by maintaining suitable environmental conditions for performance of safety functions. 3. GDC 5 requires that SSCs important to safety not be shared among nuclear power units unless it can be shown that such sharing will not significantly impair their ability to perform their safety functions, including, in the event of an accident in one unit, an orderly shutdown and cooldown of the remaining units. With regard to the CRAVS, GDC 5 requires the component parts of the CRAVS be essentially independent in order to ensure that an accident in one unit of a multiple-unit facility will not propagate to other units. Therefore the CRAVS for each unit should be designed to accommodate the load resulting from accident conditions. At the same time, the operating environment of equipment in the control room(s) of the unaffected unit(s) must be maintained within specified limits. GDC 5 requirements provide assurance that a failure or