This Standard incorporates and integrates many different approaches regarding DSA
format and content. To ensure a consistent application of this Standard among users, the
following guiding principles are provided.
The focus of this Standard is primarily on Hazard Category 2 and Hazard
Category 3 facilities.
Hazard analysis and accident analysis are merged into one chapter (Chapter 3)
to ensure that the proper emphasis is placed on identificatio n and analysis of
hazards. The hazard analysis distinguishes when accident analysis is required
as a function of potential offsite consequence. Guidance for hazard and
accident analysis is not based on probabilistic risk assessment (PRA).
Defense in depth, worker safety, and environmental issues are identified
Defense in depth as discussed in this Standard, consists of two components:
Equipment and administrative features providing preventive or mitigative
functions so that multiple features are relied o n for prevention or
mitigation to a degree proportional to the hazard potential.
Integrated safety management programs that control and discipline
Guidance is provided for evaluating the safety of a facility for which
documentable, deterministic design basis accidents (DBAs) do not exist in
order to establish bounding accidents (derivative design basis accidents) that
envelope the safety of existing facilities. Guidance is also provided on the
treatment of beyond design basis accidents.
Distinction is made between "safety-class (SC) structures, systems, and
components (SSCs)," and "safety-significant (SS) structures, systems, and
components," and the balance of facility structures, systems, and components.
Safety-class structures, systems, and components are related to public
protection and are defined by comparison with the numerical Evaluation
Guideline (EG). (See Appendix A of this Standard for additional guidance.)
Safety-significant structures, systems, and components are identified for
specific aspects of defense in depth and worker safety as determined by the
hazard analysis. Specific definitions are provided for these two terms.
Guidance is provided identifying Administrative Controls that are major
contributors to defense in depth, whic h are designated as Specific
Administrative Controls (SAC). This Standard, along with DOE-STD-1186
Specific Administrative Controls, provides guidance applicable to these types
of controls. SACs provide preventive and/or mitigative functions for specific
potential accident scenarios, which also have safety importance equivalent to
engineered controls that would be classified as safety-class or safety-