The DSA preparation process is illustrated in Figure I-2. The level of detail provided in
the DSA depends on numerous factors. Applying the guidance for the graded approach
in this Standard will assist the preparer in establishing an acceptable level of detail.
The foundation for effectively preparing a DSA is the assembly and integration of an
experienced preparation team. The size and makeup of the team depend on the magnitude
and type of facility hazards and the complexity of the processes that are required to be
addressed in the DSA. In determining the makeup of the preparation team, careful
consideration should be given to the key hazard analysis activity. In general, the safety
analysis base team should include, as a minimum, individuals experienced in process
hazard and accident analyses, facility systems engineers, and process operators.
Individuals with experience in specific subject matter such as nuclear criticality,
radiological safety, fire safety, chemical safety, or process operations may be needed in
the hazard analysis on a regular or as needed basis. Such individuals will typically be
necessary in the development of programmatic DSA chapters as well. Consistent,
accurate exchange of information among the team members is at least as important as the
makeup of the team itself. This can be assured through meaningful integration of the
Once team makeup is determined, base information needed to support DSA de velopment is
gathered. 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. Other information a rises from existing sources
such as process hazards analyses (PrHAs), fire hazards analyses (FHAs), explosive safety
analyses, health and safety plans (HASPs), environmental impact statements (EISs), etc.
The need for additional or specific information becomes apparent throughout the hazard
analysis process. The remaining key steps for efficient completion of the safety analysis
and the DSA development process are:
Identify the DSA project functions using project information and ensure the team
matches the functions that are required.
Perform hazard analysis to provide facility hazard classification, evaluate worker
safety and defense in depth, and identify unique and representative accidents to be
carried forward to accident analysis. Safety-significant SSCs, SACs and TSRs are
designated in hazard analysis as well, with a preference given to safety-related
SSCs over SACs.
Perform an accident analysis and assess the results to identify any safety-class
SSCs, SACs and accident specific TSRs based on comparison of accident
consequences to the Evaluation Guideline.
Develop the chapters for the DSA by providing information necessary to support
the results of the safety analysis. These chapters detail the results of the analysis,
describe the facility and the safety SSCs, and the safety management programs
that relate to the facility safety basis.
Prepare the Executive Summary.