General Provisions - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 5

activity). (See comments of the authors on the
standard in the topic Smith & Simpson, 2001.
Among other topics devoted to critical systems
for control, protection or monitoring in different
industry branches, Cluley, 1994 and Storey, 1996
can be mentioned.
IEC, 2011, providing a detail description
of general requirements on functional safety
applicable to NPPs, instead of the term E / E /
PE systems introduces a more common term in
industrial automatics - I&C systems, defining
them as “system, based on electrical and/or elec-
tronic and/or programmable electronic technology,
performing I&C functions as well as service and
monitoring functions related to the operation of
the system itself.” In turn, the term I&C function
is defined as “function to control, operate and/or
monitor a defined part of the process.”
The general concept of “instrumentation and
control system” covers:

• Overall I&C systems, providing monitor-
ing and control of all technological systems
and equipment at the NPP or an individual
NPP unit.

• Individual I&C systems, together perform-

ing all I&C functions provided for overall
I&C system, interacting with each other,
with operating personnel and technologi-
cal systems and equipment.

Each individual I&C system participates in
one or several I&C functions, being operational
autonomous, reasonably separate, and can be
considered in the process of design, packaging,
assembling, adjustment, testing and operation
individually and independently from other com-
ponent parts of the overall I&C system, in which
it is contained (Figure 1).
Based on functional characteristic, individual
I&C systems can be divided into:

Figure 1. Overall I&C system