The Design Bases Rule (DBR) Set specifies which specific requirement sources will be included in the Configuration Management System (CMS). DBRs can be as precise or as general as desired, ultimately affecting only the scope of material included in the CMS. The Design Bases Rules are designed to allow the CMS developer to control the scope of the material within the CMS. Since the cost of implementation is directly related to the scope of material included, this is a feature that allows the developer the ability to manage the cost of retro-fitting the CMS into an existing installation.
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A decision was made to treat all requirements uniformly regardless of source. While the CMS will keep track of which requirements are regulatory versus those that are not, the requirement hierarchy does not specify a difference. As a result, concepts such as Design Bases Values and Controlling Parameters (and the associated confusion) are eliminated.
Requirements are captured verbatim within the CMS regardless of source, and are parsed (i.e., broken down into smaller parts) as necessary to produce manageable Design Bases Specifications. Software technology makes management of large numbers of complex requirements feasible, and opens up the possibility that in the future, if requirement sources adopt common technology for transfer of data, the CMS would read requirements directly from the regulator and other sources.
Design Bases Specifications (DBS) translate the parsed requirements into high level statements that describe how the specific nuclear production facility will implement the requirement. Structure, System, and Component Specifications (SSCS) translate plant-specific DBSs into statements that specify how individual structures, systems, and components (SSCs) will implement the DBSs.
From SSCSs, we move into the historical engineering work. SSCSs generate three classes of information: Supporting Design Information, Design Parameters, and Supporting Operating Information. Supporting Design Information (SDI) is the set of documents that design and procure individual components, including calculations, drawings, purchase specifications, and orders. Design Parameters (DP) are the values that define characteristics, set points, and limits associated with facility structures, systems, and components. Finally, Supporting Operating Information (SOI) is the set of procedures and operational documentation necessary to fulfill specific requirements.
Note that the SSCSs flow down to the documentation (i.e., the SSCSs are implemented using documentation). Then it is the documentation that specifies the SSC, not the other way around. Finally, at the bottom of the hierarchy, each SSC in the physical facility is represented and connected to the requirements that specify the SSC.