Safety Structures, Systems, and Components

DOE-STD-1104-96

other hazardous materials, and consideration of the need for analysis of

accidents which may be beyond the design basis of the facility.

The hazard analysis results are clearly characterized in terms of public

safety, defense in depth, worker safety, and environmental protection.

The logic behind assessing the results in terms of safety-significant

SSCs and designation of TSRs is understandable and internally

consistent.

Subsequent accident analysis clearly substantiates the findings and

delineations of hazard analysis for the subset of events examined and

confirms their potential consequences. Events potentially exceeding

evaluation guidelines need to clearly identify associated safety-class

SSCs and basis of TSR deviations.

The goal of the review is to ensure that the safety basis is comprehensive relative to

hazards presented and is based on a consistent, substantiated logic.

2.3

Safety Structures, Systems, and Components

The next DSA approval basis is safety structures, systems, and components.

Identification of safety SSCs (i.e., safety-class SSCs and safety-significant SSCs) is a

product of the hazard and accident analyses. Determining the adequacy of safety SSCs

generally entails being able to conclude that the DSA contains sufficient documentation

and basis to arrive at the following conclusions:

The safety SSCs identified and described are consistent with the logic

presented in the hazard and accident analyses.

Safety functions for safety SSCs are defined with clarity and are

consistent with the bases derived in the hazard and accident analyses.

Functional requirements and system evaluations are derived from the

safety functions and provide evidence that the safety functions can be

performed.

Control of safety SSCs relevant to TSR development is clearly defined.

2.4

Derivation of Technical Safety Requirements

Derivation of technical safety requirements is the next of the DSA approval bases.

Hazard controls are derived to eliminate, limit, or mitigate hazards and are generally

safety SSCs or commitments to safety management programs, which are ultimately

included in TSRs. Identification of TSRs results from the most significant preventative

and mitigative features identified in the hazard and accident analyses and from the

designation of safety SSCs. Determining the adequacy of the derivation of TSRs

generally entails being able to conclude that the DSA contains sufficient documentation

and basis to arrive at the following conclusions:

TSRs are identified to ensure adequate protection of workers, the public,

and the environment.

The bases for deriving TSRs, that are identified and described in the

hazard and accident analyses and safety SSC chapters, are consistent

with the logic and assumptions presented in the analyses.