Environmental Engineering Reference
In-Depth Information
KEY TERMS AND DEFINITIONS
I&C system related to substitution of individual
components by more up-to-date ones and requiring
changes in the accepted design and design and /
or operational documentation.
Platform (Equipment Family):
A set of
hardware and software components that may work
co-operatively in one or more defined architectures
(configurations). An equipment family usually
provides a number of standard functionalities (e.g.
application functions library) that may be com-
bined to generate specific application software.
Safety Classification:
Differentiation of the
system or its components into classes, depending
on their influence on NPP safety.
Single Failure Principle:
A criterion which
requires performing all specified functions in any
postulated initiating event, combined with a failure
of one (any) element independent from this event.
Common Cause Failures:
A simultaneous
failure of two or more elements in different redun-
dant parts due to one and the same cause, which
can result in a failure of I&C function class.
Diversity:
A property related to a group of two
or larger number of I&C systems and SHC, which
simultaneously and independently perform func-
tions identical for achieved safety purposes and
differ from each other by the operating principle,
structure, applied component parts, software and
/ or other attributes or achieve the target goal in
different ways.
Human-Machine Interface:
The interface
between operating staff and I&C system and com-
puter systems linked with the plant. The interface
includes displays, controls, and the operator sup-
port system interface.
Modernization:
A set of actions for improve-
ment of safety, functional abilities, reliability and
/ or technical and economic measures of an active
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