Rod Group and Individual Control System - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 345

applied. Safety principles provided by Ukrainian
regulatory documents (NP, 2000; NP, 2008,a) and
recommended in International standards (IAEA,
2000; IAEA, 2002; IEC, 2011) were realized, that
provide reliability, quality, stability and indepen-
dence of performed functions.
Reliability of functions performance is provid-
ed by fulfilling the requirements to prevention and
protection of common cause failures, following of
single failure principle, reservation and diversity
principles, provided personnel error preventive
measures, protection from unauthorized access,
embedded technical diagnostic means.
Requirements to prevention and protection of
common cause failures take into account limiting
conditions for operation at places of each operating
stand-alone component parts (device), influence of
abnormal nature influences, personnel error dur-
ing performance and maintenance, errors during
software development, etc. Means directed toward
common cause failures prevention and protection
are foreseen and realized, correspond to nuclear
and radiation safety actual norms and regulations,
provided by Ukrainian and international regulatory
documents, and minimize possibility of occur-
rence of causes, which could call such failures.
Requirement to single failure principle obser-
vance , regimented in SHC E&PRP documents,
is provided during development and check-up
during deliverable complete set validation. Single
failure influence on group and individual control
function performance is limited by only one CR.
For observance of reservation principle in SHC
E&PRP are provided the following:

◦ Duplicated of signals transmission
lines of emergency and accelerated
preventive protection from each sig-
nals forming cabinet to all power con-
trol channels (see Figure 4);
• Duplicated of formers in CR position cabi-
nets and signals transmission lines from
each PR position cabinet to respective
channel forming output signals in signals
forming cabinet (see Figure 5);
• Duplicated of channel forming control sig-
nals in signals forming cabinets and control
buses from each signals forming cabinet to
all power control channels in power control
cabinets (see Figure 6);
• Triplicate redundancy of connecting ields
in manual input elements (keys, switchers,
buttons) monitoring and control panel and
lines connecting these elements to each
signals forming cabinet (see Figure 2);
• Duplicated of CR position indication de-
vices, one of which is placed in MCR, the
other - in ECR, and capability to display
data on each CR positions on the panel
computer monitor, embedded in MCP, and
on workstation monitors;
• Triplicate redundancy of SHC E&PRP pri-
mary power sources, duplicated primary
and secondary power sources of operating
stand-alone component parts;
• Duplicated of supply voltage transformers
embedded in operating stand-alone com-
ponent parts.

Emergency protection commands received by
each channel (signals forming cabinet) from the
respective channel of the first and second SHC
E&PRP sets are connected in pairs in accordance
with “OR” logical condition and multiplied with
the help of active elements in the base and reserve
safety signal forming channels (see Figure 4).
Then these signals are sent to all power control

• Triplicate redundancy with voter of signals

forming cabinets (see Figure 2) and dupli-
cated of channels forming safety signals
in each signals forming cabinet and power
control channels in each power control
cabinet (see Figure 4);