Safety Structures, Systems, and Components
PU R P O S E . The purpose of this DSA chapter is to provide information necessary to
support the safety basis requirements of 10 CFR 830 for derivation of hazard controls.
This chapter provides details on those facility structures, systems, and components that are
necessary for the facility to protect the public, provide defense in depth, or contribute to
worker safety. Similarly, this chapter p rovides details on specific administrative controls
that are significant to specific accident risk reduction. Descriptions are provided of the
attributes (i.e., functional requirements and performance criteria) required to support the
safety functions identified in the hazard and accident analyses and to support subsequent
derivation of TSRs. Expected products of this chapter, as applicable based on the graded
Descriptions of safety SSCs and SACs including safety functions.
Identification of support systems safety SSCs depend upon to carry out safety
Identification of the functional requirements necessary for the safety SSCs and
SACs to perform their safety functions, and the general conditions caused by
postulated accidents under which the safety SSCs or SACs must operate.
Identification of the performance criteria necessary to provide reasonable
assurance that the functional requirements will be met.
Identification of assumptions needing TSR coverage.
Existing supporting documentation is to be referenced. Maximum advantage should be
taken of pertinent existing safety analyses and design information (i.e., requirements and
their bases) that are immediately available or can be retrieved through reasonable efforts.
Include a brief summary for each such reference that explains its relevance to this chapter
and provides an introductory understanding of the reference.
AP P L I C A T I O N O F T H E GR A D E D AP P R O A C H . Hazard Category 3 facilities
will not have safety-class SSCs and the number o f safety-significant SSCs and SACs if
any, will be less than that of a Hazard Category 2 facility due to the reduced magnitude of
hazards. As noted in Chapter 3, "Hazard and Accident Analyses," a possible exception to
this general guidance pertains to che mical hazards. The hazard classification mechanism
used in DOE-STD-1027-92 does not consider potential hazardous chemical releases. It is
possible that a Hazard Category 3 facility could need safety-class items for large chemical
hazards, although it is not typically expected.
Hazard Category 2 facilities have the potential for an accident resulting in significant
onsite consequences and may have offsite consequences. These facilities