Bases - std30240020

DOE-STD-3024-98

other adverse impacts, or are necessary to satisfy

Safety Requirements

other DOE programmatic mission considerations.

a. Safety Class

b. Safety Significant

The General category is used for requirements that

c. Other Safety Requirements

do not fit into the other categories.

Environmental Requirements

Mission-Critical Requirements

This set of classifications is based on DOE-STD-

General Requirements

3009 for nuclear facilities.

This set of

classifications, a modified set, or a completely new

Requirements classified as Safety-Class or Safety-

set of classifications may be used for nonnuclear

Significant are those identified as necessary for

facilities.

Safety-Class and Safety-Significant SSCs to

accomplish their safety functions, as established as

established by the hazards analysis and safety

Bases

analysis processes.

The "Other Safety

Requirements" classification applies to those

A major function of the SDD is not only to state the

requirements that, although not classified as Safety-

engineering requirements on the system, but also to

Class or Safety-Significant, still perform functions

explain the basis for those requirements. Basis

considered important to overall facility safety and

information explains why the requirement exists,

are part of worker safety or the defense-in-depth

why it is specified in a particular manner, and why it

safety basis for the facility.

has a particular value. While it is highly desirable

that the bases for all requirements be documented in

The safety requirements statements shall be

the SDD, it is imperative that the basis information

consistent with, and be explicitly correlated back to,

for safety requirements be stated in the SDD.

the corresponding statements of functional

requirements and performance criteria in the facility

Technical basis information shall be included

FSAR, TSRs/OSRs, and other authorization basis

directly in the body of the SDD immediately after

documents, if the authorization basis has already

the requirement, rather than relegate such

been established for the facility. One convenient

information to an appendix or refer to another

way to correlate these requirements is to use

document. However, the basis may be provided in

footnotes. For example, a footnote to a particular

one place for a group of related requirements. The

requirement statement might say, "This requirement

bases for the requirements should be presented in a

corresponds to Requirement 4.4.3.8 on Page 4.4-12

manner that minimizes the disruption of the reader's

in the FSAR (Reference 3 in Appendix A)." An

flow of thought. The recommended manner for

alternate way to correlate these requirements is with

presenting the basis information is to provide it in

a table (for example, a requirements matrix) in a

separate paragraphs that are set off in a special

separate Appendix or Attachment to the SDD.

format or font that is clearly discernable. The

following example illustrates this approach:

Often the Environmental Protection category is

omitted from requirement classification lists.

Sometimes environmental protection is taken to be a

subset of safety in general. The environmental

protection category should be considered separately

and explicitly in the SDD in order to make sure that

this important set of requirements is not overlooked

and to address requirements related to environmental

permits.

Mission-critical functions are those that are

necessary to prevent or mitigate substantial

interruptions of facility operations or severe cost or

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