Emergency and Preventive Reactor Protection Systems - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 308

Figure 1. Software-hardware complex of emergency and preventive reactor protection system (SHC
E&PRP)

condition “two of three” and are transferred via
communication lines to RG&IC system, TCS and
RPwCUL&APP system from the cross output
cabinet of each set (not represented in Figure 1).
The possibility of current, diagnostic and archived
data output from workstation to CIS is provided.
The components of SHC E&PRP set and in-
terconnections are shown at Figure 2.
For digital message exchange between signal
forming cabinets and transfer of messages that
forms in signal forming cabinets and the cross
output cabinet to workstation, local networks with
100BASE-FX interface and end-to-end topology
are used, shown in Figure 2. Automated operator
and technologist workplaces are connected to
Workstation according to the standard serial
digital data channel (usually one of the Ethernet
network variants), which is supported by Worksta-
tion server and Industrial PC, on which base the
automated operator and technologist workplaces
are implemented. The way of workstation con-
nection to CIS is defined for each power unit with
regard to data input interface used for the current
CIS.
Signal forming cabinet performs:

• Reception of direct current analog signals:

◦ From pressure sensors, pressure dif-
ferential sensors, level sensors;
◦ From normalizing transducers of
power and frequency alternating cur-
rent powering main coolant pumps;
◦ From thermoelectric transducers (low
voltage direct current);

• Reception of discrete signals:

◦ From NFMS (excess of neutron
power values and decrease of power
change period);
◦ From the voltage monitoring equip-
ment on the irst and second alternat-
ing current input 380 V (power sup-
ply loss);
◦ From IRMS (decrease permissible
reserve to boiling crisis on the fuel el-
ement surface, excess of local power
density limit, coolant temperature
raise on the outputs of individual fuel
assemblies over the limit);
◦ From RG&IC system (insertion of at
least one of CR into the core);