Document: NUREG-0800
Document ID: 2781386f-8b2c-401b-814a-d98c9381a202
Document Type: srp
Title: STRUCTURES, SYSTEMS, AND COMPONENTS TO BE PROTECTED FROM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070307.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.5.2
CFR Part: 
CFR Title: 

Content:
ign bases, design criteria, descriptions and safety evaluations, together with the system and component characteristic tables and safety classification tables are reviewed to identify safety functions performed by the SSC. In general, the safety functions to be performed by the SSC in various designs remain essentially the same. However, the location or arrangement of the SSC and the methods used vary from plant to plant depending upon the individual designer. The reviewer identifies variations in design and evaluates them on a case-by-case basis. The second step in the review is to determine the SSC, or portions of SSC, that require protection against externally generated missiles. The reviewer uses engineering judgment and the results of failure modes and effects analyses in conjunction with the results of reviews under other SRP sections for specific SSC in determining the need for missile protection. Most safety- related systems are located within structures that are resistant to external missiles by virtue of design for other purposes (e.g., primary containment), or because the structures are constructed specifically to withstand missiles. Systems and components located within such structures are considered adequately protected. The reviewer concentrates his attention on safety- related SSC located outside such structures and on penetrations and access openings in the structures. Essential service water piping and components, storage tanks, and ultimate heat sink components are examples of SSC typically located outside missile-resistant structures. Site specific systems such as the ultimate heat sink may be excepted from the scope of design certification. The detailed review of the site specific systems to be protected from missiles for a standardized design is therefore typically deferred until review of applications referencing the certified design. Depending on the nature and source of the externally generated missiles, protection 18 may be provided by