The process of developing a DSA is a process that may require numerous iterations
depending on the complexity of the facility and the level of detail required. The hazard
and accident analyses (hazard analysis is adequate for Category 3 facilities) are the central
elements of this process. The results of the hazard analysis form the basis for grading the
level of detail necessary to ensure an acceptable DSA. The hazard analysis specifically
identifies safety-significant SSCs and SACs for defense in depth and worker safety, and
TSR controls. The results of the accident analysis form the basis for determining
additional safety controls imposed on the facility (e.g., safety-class SSCs and TSRs) as a
function of the Evaluation Guideline. These specific controls are then factored into overall
safety management programs that ensure the operational discipline required by the hazards
identified is maintained.
Several specific topics are directly relevant to understanding the conceptual basis of this
Standard. These topics are worker safety, defense in depth, programmatic commitment s,
SSC and TSR commitments, and correlation of this Standard to 10 CFR 830 requirements.
The remainder of this section discusses each of these topics in discrete subsections.
Workers, typically those in close proximity to operations, are the population principally at
risk from potential consequences associated with Hazard Category 2 and 3 facilities. The
DOE recognizes, via 10 CFR 830, the importance of including worker safety in safety
analyses by specifically noting the worker as a populat ion of concern. Developing a
conceptual basis for the methodology used in this Standard requires answering the
fundamental question of how worker safety is most appropriately addressed in the DSA.
The Occupational Health and Safety Administration (OSHA) has published 29 CFR
1910.119, "Process Safety Management of Highly Hazardous Chemicals." OSHA defines
the purpose of this regulation in summary fashion as, "Employees have been and continue
to be exposed to the hazards of toxicity, fires, and explosions from catastrophic releases of
highly hazardous chemicals in their workplaces. The requirements in this standard are
intended to eliminate or mitigate the consequences of such releases." Many of the topics
requiring coverage in this federal regulation, such as design codes and standards, process
hazard analysis, human factors, training, etc., are directly parallel to the requirements in 10
DOE O 440.1 and the OSHA standard address the issue of worker safety from process
accidents by requiring the per formance of hazards analyses for processes (exclusive of
standard industrial hazards) in conjunction with implementation of basic safety programs
that discipline operations and ensure judgments made in hazard analyses are supported by
actual operating cond itions. These requirements effectively integrate programs and
analyses into an overall safety management structure without requiring quantitative risk
assessment. This integration and the basic concepts of Process Safety Management (PSM)
described by OSHA regulations and the manuals and codes of practice described in DOE
O 440.1 are philosophically accepted as appropriate for DSAs. This Standard effectively
merges PSM principles with traditional DSA precepts.