Checking Remote Position Indicators

DOE-STD-1036-93

4.3.4

Checking Remote Position Indicators

Independent verification should always be performed locally, unless

precluded by exposure to radiation, hazards, or other overriding factors.

In those limited situations, independent verification may be performed

using remote position indicators. The most common of these are

indicating lights.

Remote position indicators may seem to represent an ideal method for

independent verification. However, equipment failures in the sensor,

signal transmission, or display device can cause valve-position-indicating

lights and other control board indications to be incorrect. Some failures

of this type have gone undetected for a significant length of time.

Independent verification using remote position indicators should be

checked using other verification methods, such as process parameters,

whenever possible.

4.3.5

Surveillance (Operational) Testing

Certain systems and components are subject to periodic surveillance

(operational) tests due to regulatory requirements. In many cases, the

nature of the test qualifies it as an independent verification of system

alignment and capability. For example, a full-flow test of a system can

prove that the alignment of components and positioning of flow-

controlling valves is correct. This means of proving operability is not the

same as the means used to establish the position of the components, and

therefore is independent of the original activity.

Some surveillance tests may not test the components in their operating

configuration, or they may not include all the components that would be

required for operation. For example, running a pump in recirculation to