of the documentation for the proposed change. If it is determined that the proposed
change could impact an SSC that is part of the configuration management equipment
database, then the proposed change will need to be processed through the change control
process. Furthermore, following review and approval of the proposed change, the
configuration management equipment database will need to be updated as appropriate to
reflect the change.
3.11.2 Safety Basis
Section 3.2 discusses how the Safety SSCs identified in the DSA constitute the baseline
set of SSCs that are to be controlled under the configuration management process. It also
discusses including other SSCs such as those identified as necessary for:
critical mission functions,
protection of costly equipment or functions,
protection of adjacent SSCs, or
critical software functions
Configuration management should be used to control and document changes to the safety
basis (including the DSA and the Technical Safety Requirements or TSRs). The
relationship of the process of documenting the configuration management design
requirements to the safety basis required by Subpart B of 10 CFR Part 830 for hazard
category 1, 2, and 3 nuclear facilities is illustrated in Figure 3-6.
The relationship of the Unreviewed Safety Question (USQ) process to configuration
management is addressed in the discussion on change control in Chapter 5.
3.11.3 Design Basis versus Design Requirements
The design requirements are the output of the design process as shown in Figure 3-4.
The design basis provides the technical and analytical basis for the design requirements.
The design requirements specify "what" is required and the design basis documents
"why" a design requirement is specified. In addition to safety basis documents (DSAs
and TSRs), design basis information is found in other documents, such as transient
calculations, setpoint calculations, and sizing calculations.
There may be differences between the values in the design bases and the design
requirements for a facility or activity. For example, the design basis may specify a
requirement for a pump to deliver 160 GPM, while the design requirements may specify
a pump rated to deliver a flow of 200 GPM. This difference may represent conservatism
that the design engineer felt was appropriate or the higher rating may have been chosen to
match the rating of an available, off-the-shelf pump.