Rod Group and Individual Control System - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 340

ceived signals in basic and reserve blocks
by “two of three” condition; relieve of
power supply voltage by alternating and
direct current (disconnecting of power sup-
ply of electromagnet drives, which causes
CR fall) in case of receiving of control
signals from, at least, two signals forming
cabinets;
• Receiving of digital messages from each
of three signals forming cabinet via ba-
sic and reserve control buses (see Figure
6); logical processing of the received data
(control commands) in basic and reserve
blocks; forming and sending to CR drive
electromagnets of impulse sequence (cy-
clograms), which initiate CR movement in
case of receiving of commands from two
or three signals forming cabinet; forming
and sending of CR holding current in case
of absence of control signals from, at least,
two signals forming cabinet, as well as by
drive stop signal received from the adja-
cent channel in CR position cabinet;
• Automatic switching to reserve input of
power supply by direct current for CR
holding in case of losing of alternating cur-
rent power supply or force control circuit
failure (in case of simultaneous current de-
crease of locking and ixing electromagnets
to 50% of the nominal holding current);

supplied by rectified current from basic power
supply source, the other is supplied by direct cur-
rent from reserve source (accumulator battery).
Both blocks outputs are parallel-connected to
CR drive electromagnet winding (commutator is
not required for switching from the basic block
to reserve). While performance from the reserve
source drives controllability is preserved. The pos-
sibility of in-line electromagnets current change
is provided (within the range from 100% to 200%
of the nominal values).
Embedded diagnostic equipment performs
continuous automatic monitoring over power
control cabinet component parts technical con-
dition, electromagnets and communication lines
condition (resistance and inductance of coils,
insulation resistance, absence of disconnection
and short circuits). Diagnostic messages on are
sent to workstation via diagnostic and archiving
bus. Generalized signal about faults is sent to
workstation via separate line.
Monitoring and Control Panel has:

• Switcher to 11 ixed positions, with the
help of which one of ten CR groups is se-
lected for manual control, or mode is set,
which in case of manual control groups
move one by one in a strict design order;
• Switcher to 4 ixed positions with the help
of which one of CR groups (number 8, 9
or 10) is selected as the main for automatic
power regulation, or mode is set, which by
the automatic regulation command (B↑ or
D↓) groups move one by one in a strict de-
sign order;
• Buttons without mechanic locking for
selection of CR, which is selected for in-
dividual control (buttons are set on reac-
tor core map- see Figure 1; indication is
performed by button after its pushing and
lightning map symbol of selected CR);
• Keys on three positions: for selected CR
group control (or groups in a strict design
order); for control of the ifth group, which

• Forming and sending of impulses while

each CR movement on one step upwards
or downwards and while disconnecting
of power supply of drive electromagnets,
which is caused (separately) by ERP,
RAPP command and actuation of automat-
ic power supply switcher to the adjacent
channel in CR position cabinet.

Power control channel has automatic switch-
off of basic block outputs in case of reserve
block performance, and renewal of basic block
performance in case of control return to it.
Both blocks are equal, however, one of them is