Component Boundary Determination

DOE-STD-1052-93

6.2

A boundary for the selected components should be established to ensure that

associated devices are appropriately considered in the analysis. The boundary for a

component should be established as a logical grouping of devices or components

based on the function of the component. All attendant devices necessary for the

component to perform its system function should be included within the boundary.

For example, if a spray valve is identified as a problem component, then the valve

operator, valve positioner , and current-to-pressure converter should be included in

the boundary. Accurate and inclusive boundary determination is important because

the unreliability of the valve may be caused by seemingly unrelated failures of these

devices or it may be determined that the unreliability is primarily due to only one of

the devices, in which case, the boundary may be redrawn to focus the analysis on that

device.

If a larger component, such as a main feedwater pump, is selected, the boundary for

the pump, which may be considered a subsystem of the feedwater system, may be

established as described in Section 7.4, "Subsystem Boundary Determination," and

analyzed using the guidance described in Section 7, "System Analysis."

When establishing the component boundary, also consider the devices associated with

an equipment identifier since maintenance and operating history is usually most easily

retrievable using those identifiers.

6.3

Component History Review

All appropriate operating characteristics, requirements, vendor maintenance

recommendations, and history records of a component should be identified and

considered in analysis of the component. History review and data collection may be

time-consuming depending upon the individual plant's facilities. They are efforts that

are performed throughout the analysis process. The information collected should be

compiled into a data package to facilitate future use, reference, and ready access. All

documentation developed during the analysis of components should be retained for

use in the analysis described in Section 7, "System Analysis."

The data sources listed in Attachment A should provide the design and operating

information needed to determine component functions and to perform the component

analysis. The information needed includes the following:

design specifications

operating requirements

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