Properties of Safety Important I&C Systems and their Components - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 71

Figure 4. Design limits and selection of set-points of I&C systems

In case of operational events the safety actua-
tion I&C system:

• Archives data of commands, obtained from
the safety protection I&C system, normal
operation I&C systems and operational
personnel, results of automatic diagnostic
and detected operability failures of own
components and adjacent equipment.

• By commands from the safety protection
I&C system forms and issues control sig-
nals to actuating elements of technologi-
cal systems and equipment (gate valves,
pumps, electric motors, control valves,
сontrol rod drives, etc.) required for per-
formance of protective actions initiated by
these commands.
• Prohibits execution of commands that can
be issued by other protection I&C sys-
tems, normal operation I&C systems and
/ or operational personnel in case they are
not compatible with executed protective
actions.
• Displays information required for opera-
tional personnel to control executed actions
and if necessary perform remote control of
technological equipment.

• Forms and issues messages to other I&C

systems about condition of operation of
own components and adjacent equipment.

For each safety actuation I&C system the fol-
lowing is defined in the design: a list of sources
of commands (safety actuation I&C systems,
normal operation I&C systems, equipment of main
control room and / or emergency control room); a
list of command receivers (actuating elements of
technological systems and equipment); algorithms
for formation of control signals required delays
of output and / or withdrawal of control signals
(if necessary); compliance of logic conditions of
each discrete output signal with values of physical