Document: NUREG-0800
Document ID: f03d2c71-27a1-41fd-9362-1e62c6142e13
Document Type: srp
Title: Containment Systems and Severe Accidents (Tier 1)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070653.pdf
Revision Date: 2023-06
Chapter: 14
Section ID: 14.3.11
CFR Part: 
CFR Title: 

Content:
to safety in the Tier 1 design descriptions. The level of detail in Tier 1 governed by a graded approach to the SSCs of the design, based on the safety significance of the functions they perform. The design descriptions include the figures associated with the systems. The design descriptions serve as binding requirements for the lifetime of a facility to assure that the plant does not deviate from the certified design. The scope of the certified design is defined by the information in the DCD. Therefore, each branch should ensure that all appropriate systems that are either fully or partially within the scope of the design certification are addressed in Tier 1, at the appropriate level of detail based on the safety significance of the SSCs. For example, safety-related SSCs should be described in Tier 1 with a relatively greater amount of information. Other SSCs should also be included based on their importance to safety, such as containment isolation aspects of non-safety systems. Some non-safety aspects of SSCs need not be discussed in Tier 1. This graded approach recognizes that although many aspects of the design are important to safety, the level of design detail in Tier 1 and verification of the key design features and performance characteristics should be commensurate with the significance of the safety functions to be performed. 14.3-21 DRAFT Rev. 0 - April 1996 The design descriptions include a narrative and simplified schematic figures in Tier 1, where the figures are provided. The narrative should state the system purpose, significant performance characteristics and safety functions, whether it is safety-related or not, system location, key design features, seismic and ASME code classifications, description of system operation, major controls and displays, logic circuits, interlocks, Class 1E power sources and divisions, equipment to be qualified for harsh environments (and other than harsh for certain I&C equipment), and interface requirements, as