Rod Group and Individual Control System - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 346

channels in power control cabinets via separate
electrical lines. In the base and reserve block of
each power control channel logical processing
of signals received via three independent lines
from the base and reserve safety signal forming
channels in first, second and third signals forming
cabinet (by “two of three” condition). The base
or reserve block removes alternating and direct
current power supply from electromagnets of the
controlled СR drive in case of presence of two or
three protection signals at the input. Thus, com-
mands from outputs first, second and third channels
of the first and second SHC E&PRP preserved to
end blocks, directly controlling electromagnet CR
drives, besides, in each channel two independent
inter-redundant ways for emergency protection
command passing are provided.
For diversity principle realization during emer-
gency reactor protection command performance
has two different executive devices. One of them
is SHC RG&IC itself, which by ERP command
removes power at the base and reserve block power
control channels outputs. Functions of the second
executive device performs equipment, which by
the same command of the first and / or second
SHC E&PRP sets performs mechanical circuit
disconnection, disconnecting of power supply all
power control cabinets from alternating and direct
current power supply.
Requirements to personnel errors prevention
are regimented in SHC RG&IC documents in
compliance with formulations of applied to it
norms and regulations NP, 2000. They are related
to identification and location of manual input and
data visual display means location, diagnostic
information imagery, protection from unauthor-
ized access, compatibility and labeling plug-in
component parts, operational documentation.
Technical decision and organizational means were
realized, which exclude the possibility of:

• Simultaneous removal of two SFC signals
forming cabinets;
• Changing of CR misalignment set-point
without personnel's warning;
• Selection of more than one CR group and
more than six CR for manual control;
• Upwards group movement when operator
performs pure condensate insert feeding;
• Unauthorized access to cabinets, their
component parts, databases, software and
archives.

Requirements, aimed at exclusion or mitigation
of personnel's errors consequence are considered
during development of embedded diagnostic and
diagnostic information imagery means, as well
as operator actions supporting means (human-
machine interface).
Quality of functions performance is provided
by rate setting and requirements fulfillment to
accuracy and time characteristics, as well as to
human-machine interface.
SHC RG&IC-R accuracy characteristics are
set for sending to IRMS data on CR position, define
of CR misalignment in each group and measuring
of CR falling duration. Misalignment is calculated
and displayed on the monitoring and control panel
in digital and quasi-analog form of absolute units
with 1% discretion. Absolute measurement error
allowable limits of CR falling duration in operation
condition are ± 0.01 s. Position indication error
does not exceed 20 mm while using of stepwise
sensors of control rod position (in case of other
type sensors usage the error raises only on the
intermediate sections border of rod working stroke,
and is defined by sensor).
Requirements to time characteristics are
regimented with regard to Ukrainian regulatory
documents (see Chapter 3), compliance with SHC
RG&IC-R set requirements confirmed during
validation of deliverable complete set.