Document: NUREG-0800
Document ID: 3571c656-1693-466b-a77d-6c05b7eed41e
Document Type: srp
Title: REACTOR SYSTEMS - INSPECTIONS, TESTS, ANALYSES, AND
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0706/ML070660623.pdf
Revision Date: 2023-06
Chapter: 14
Section ID: 14.3.4
CFR Part: 
CFR Title: 

Content:
rescribed limits, parameters, procedures, and attributes upon which the NRC relies, in a limited number of technical areas, in making a final safety determination to support a design certification.” 14.3.4-7 March 2007 14.3.4-7 March 2007 In some instances, an applicant may employ DAC to provide the staff with information to support its safety determination process. In SECY-92-053, the staff noted that “the concept of DAC would enable the staff to make a final safety determination, subject only to satisfactory design implementation and verification by the COL licensee through appropriate use of ITAAC.” The staff defined DAC as “a set of prescribed limits, parameters, procedures, and attributes upon which the NRC relies, in a limited number of technical areas, in making a final safety determination to support a design certification. The DAC are to be objective (measurable, testable, or subject to analysis using pre-approved methods), and must be verified as part of the ITAAC performed to demonstrate that the as-built facility conforms to the certified design. That is, the acceptance criteria for DAC become the acceptance criteria for ITAAC, which are part of the design certification.” The use of DAC by applicants use for I&C is considered acceptable given the rapidly changing technology for digital I&C systems. For many of the design features, it might be impractical to test their functionality because of the absence of simulated severe accident conditions. An example might be the ability of the reactor cavity to absorb the heat and radiation effects of a molten core. Consequently, the existence of the feature on a figure, subject to a basic configuration walkdown and confirmatory test reports or analysis, may be considered sufficient Tier 1 treatment. Another example in which passive designs would be difficult to verify prior to fuel loading as related to normal operations involves natural circulation. Passive designs, compared to previous designs, can