Properties of Safety Important I&C Systems and their Components - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 104

• Cycle time of data input from sensors and

other I&C systems (SHC).

of a control signal at the input of an actuat-
ing system or an element of technological
equipment (except those commands, which
should be generated with a speciied lag).
• Execution of Remote Control Commands:
Not more than 0,1 sec from the moment of
signal generation at the output of a manual
control key before occurrence of a control
signal at the input of a proper actuating ele-
ment of technological equipment.
• Warning of personnel and display of data
about dangerous initiating events, vio-
lations of design limits and conditions,
changes of monitored parameters and state
of technological equipment, actuation of
safety control systems and normal opera-
tion systems - not more than 1,0 seс from
the moment of occurrence (change) till ac-
tuation of preventive or emergency alarm
at workplaces of personnel and occurrence
of a relevant information in the speciied
format of a data display device.
• Notiication of personnel about operabil-
ity failures, which afect safety, - not more
than 10 seс (other - not more than 1 min)
from failure occurrence till actuation of
preventive alarm at workplaces.
• Archiving of data about initiating events,
violations of design limits of safety op-
eration, occurrence of conditions of gen-
eration protective action commands - 0,01
seс, data of a state of technological equip-
ment, values of monitored parameters and
set-points, violations of operational limits
and conditions, commands of restriction,
regulation, technological protection and
interlocking, discrete and remote control
- 0,1 seс between a time point of event oc-
currence and a time point at which it would
be registered in a data base and an archive.

• Time resolution during data input and

archiving.

• Lag of performance of discrete function.

• Speed of function execution.

• Rate of exchange through communication

lines and local networks.

• Time of information storage in a data base

and an archive.

• Time of start actuation after power

restoration.

Nominal value of time resolution during data
input and archiving are determined for accurate
differentiation and registration of a sequence of
initiating events, changes of state of technological
equipment and controlled parameters, actions of
control systems and personnel in an archive (for
further analysis and estimation):

• For information of initiating events, viola-

tions of design limits of safety operation,
occurrence of conditions of initiation of
safety control systems, commands of pro-
tective actions - not worse than 0,01 sec.

• For information of a state of technological

equipment, values of monitored parameters
and set-points, violations of operational
limits and conditions, commands of limi-
tation, regulation, technological protection
and interlocking, discrete and remote con-
trol - not worse than 0,1 sec.

Lags of performance of discrete functions
(maximal permissible upper values):

• Output of Protection Commands: Not
more than 0,1 seс, commands of limita-
tion and interlocking - not more than 0,1
seс from a moment of an occurrence of a
design speciic condition till an occurrence

• Sampling on an operator call and display

of information from a data base or an ar-