Determination of Preliminary Performance Category for Non-Safety Components

DOE-STD-1021-93

Method II categorization is more rigorous than Method I, since it allows assigning different

segments to different categories, and assigning non-safety segments and components to

applicable lower performance categories. However, Method I is more conservative.

(c)

Method III: Component-by-Component Categorization

In this method, each component of the NPH-related safety systems (having an entry in the

safety system-function matrix) is categorized individually following the Subsection 2.4

guidelines. Thus, each component is categorized based on its own function, and not lumped

with the entire segment or system.

Method III is the most rigorous of the three methods, but the other two methods are more

conservative. Use of this method can minimize the number of higher category components,

and thereby reduce the components that must be designed for higher level NPH design loads.

However, in order to accomplish this, detailed system safety and accident analyses will be

needed.

3.6

Determination of Preliminary Performance Category for Non-Safety Components

Other components in a facility will consist of Group II and Group III system components (see

Subsections 3.4 and 3.5), and the Group I system components that are not essential for NPH

mitigation. Preliminary performance category of these components can be determined using a

procedure similar to that described in Subsection 3.5 (i.e., by using system-by-system, segment-

by-segment, or component-by-component categorization), except that categorization will be based

on mission, worker and co-located worker life safety, and cost considerations as outlined in

Paragraphs (d), (e), and (f) of Subsection 2.4. Accordingly, these components will be placed in

PC-2, PC-1, or PC-0 (unless these are placed in PC-3 or PC-4 for improved performance

consideration only).

The data and information necessary to categorize these components may be partially available in

the facility hazard categorization documents or facility safety and accident analysis reports. If the

available data are not adequate, additional data can be obtained cost-effectively through a facility

walkdown (for existing facilities) and by interviewing facility operations and maintenance

personnel. It may also be necessary to review design documents and operation manuals and

procedures.

According to Section 2.4 guidelines, if the failure of a component can cause a life-threatening

situation (non-radiological or non-toxic) to any worker or co-located worker, it would be a PC-1

component. Since radiological and toxicity effects have already been considered in Subsection

3.5, only physical life-threatening situations, such as those resulting from NPH-related structural

failures or overturning of equipment, need to be considered in this step. Typical examples of such

situations are when structures, tall heavy furniture, equipment, piping, ducts, etc., fall on people

during NPH events or prevent egress of occupants. Components, failures of which can cause

these situations, can be identified most effectively by a facility walkdown or by a careful

evaluation of building layout plans and drawings. A convenient and efficient method of

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