Document: NUREG-0800
Document ID: f8502678-c803-47fd-90e8-98197a427d04
Document Type: srp
Title: TURBINE AREA VENTILATION SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550040.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.4.4
CFR Part: 
CFR Title: 

Content:
able regulatory positions are C.1 and C.2. For RG 1.140 Revision 2, the applicable regulatory positions are C.2 and C.3. 9.4.4-5 Revision 3 - March 2007 Technical Rationale The technical rationale for application of these acceptance criteria to the areas of review addressed by this SRP section is discussed in the following paragraphs: 1. GDC 2, as related to the system being capable of withstanding the effects of earthquakes, requires that SSCs important to safety be designed to withstand the effects of a design-basis earthquake without loss of capability to perform their safety functions. The function of the TAVS is to maintain ventilation, to permit personnel access, and to control airborne radioactivity in the turbine area during normal operation and anticipated operational occurrences and during and after postulated accidents, including loss of offsite power. This requirement ensures that, during and after a design-basis earthquake, essential portions of the TAVS will remain functional and that the failure of nonessential portions of the system or of other systems not designed to seismic Category I standards will not result in offsite doses in excess of 5 mSv (0.5 rem) to the whole body or an equivalent dose to any part of the body. Meeting the GDC 2 requirements ensures that the TAVS will operate as designed, thus providing protection against release of radioactivity exceeding regulatory limits. 2. GDC 5 requires that SSCs important to safety shall not be shared among nuclear power units unless it can be shown that such sharing will not significantly impair their ability to perform safety functions, including, in the event of an accident in one unit, an orderly shutdown and cooldown of the remaining units. For the TAVS, GDC 5 requires that the component parts of the TAVS be essentially independent to ensure that an accident in one unit of a multiple-unit facility will not propagate to other units. Therefore, the TAVS for each unit should be designed to