Document: NUREG-0800
Document ID: 39eaebb5-884c-4731-895a-8df4686b7293
Document Type: srp
Title: REGULATORY TREATMENT OF NONSAFETY SYSTEMS FOR PASSIVE
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1403/ML14035A149.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.3
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CFR Title: 

Content:
(ATWS) and in 10 CFR 50.63 for Station Blackout (SBO). B. SSC functions relied on to ensure long-term safety (the period beginning 72 hours after a design basis event and lasting the following 4 days) and to address seismic events. C. SSC functions relied on under power-operating and shutdown conditions to meet the Commission goals of a core damage frequency (CDF) of less than 1x10-4 each reactor year and a large release frequency (LRF) of less than 1x10-6 each reactor year. D. SSC functions needed to meet the containment performance goal, including containment bypass, during severe accidents. E. SSC functions relied on to prevent significant adverse systems interactions between passive safety systems and active nonsafety SSCs. SSCs scoped into the RTNSS program under a given criteria are termed RTNSS (criteria) A-E in this SRP section. For example, SSCs receiving treatment under RTNSS criterion B are termed RTNSS “B” SSCs. 19.3-4 Revision 0 – June 2014 The principal areas of the staff’s review are listed below: 1. Identification of SSC functions needed to assure that R/A missions are accomplished based on the five RTNSS criteria listed above. 2. Functional design of RTNSS SSCs to meet R/A mission. a. Adequacy of functional design requirements b. Compliance with functional design requirements c. Design improvements to minimize adverse interaction between passive and nonsafety-related active systems 3. Focused PRA sensitivity studies used to identify risk-significant SSCs in the scope of RTNSS program per RTNSS criterion “C.” 4. The augmented design standards that must be met by SSCs in the scope of the RTNSS program including seismic design standards, standards for protection against natural phenomena, standards for protection against internal hazards (e.g., internal floods) and standards for assuring that SSC functions can be achieved expeditiously. 5. The regulatory treatment proposed for SSCs in the scope of RTNSS program. COL Action Items and Design