Nuclear Plant Journal, May-June 2014 NuclearPlantJournal.com
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Kee-Choon Kwon
Kee-Choon Kwon received the B.S.
degree in Electronics Engineering from
the Kyungpook
National University
in 1980 and MS
and Ph.D. degree
in computer
science form the
Korea Advanced
Institute of Science
and Technology
in 1989 and 1999
respectively. He has
been a researcher
with the Korea
Atomic Energy
Research Institute
since 1980. His
research interests
include nuclear
instrumentation and
control system, real-time simulator, and
software verification and validation.
Safety Feature-Component Control
System (ESF-CCS), and Reactor Core
Protection System (RCOPS).
The RPS generates a reactor
trip signal and the engineered safety
feature actuation signals automatically
whenever the monitored processes reach
the predefined set points. The RPS is
designed with the redundant 4-channel
architecture, and every channel is
implemented with the same architecture.
A single channel consists of the
redundant Bi-stable Processor (BP), the
redundant Coincidence Processor (CP),
an Automatic Test & Interface Processor
(ATIP), and a Cabinet Operator Module
(COM). The BP module generates a
logic-level trip signal by continuously
comparing the sensor inputs with the
predefined trip set-points. The logic-level
trip signals generated in the BP module
of any channel are transferred to the CP
modules of all the channels via the HR-
SDL. The CP module monitors the logic-
level trip signals transferred from the four
BP modules. When two or more logic-
level trip signals from the BP channels
are activated, the CP modules will
activate the output signal for the reactor
trip. The ATIP module monitors the
operation status of the RPS, and conducts
a surveillance test to ensure a reliable
operation of the BP and the CP module in
the same channel. The test results of the
ATIP are transferred to the COM module
which has an operator interface facility
implemented with an industrial PC and a
flat panel display. The BP, CP, and ATIP
modules of the RPS are implemented
with the PLC platform.
Engineered Safety
Feature-Component
Control System
It initiates sever-
al emergency actua-
tions to prevent the
plant from a haz-
ardous state during/
after accidents. The
actuations include
a safety injection, a
containment isola-
tion, a main steam
line isolation, an
auxiliary feedwa-
ter injection, and a
containment spray
actuation.
The ESF-CCS
is designed with
four redundant divi-
sions (i.e., A, B, C,
and D), and implemented with the PLC
platform. The principal components of
an individual division are fault tolerant
Group Controllers (GC), Loop Control-
lers (LC), an ESF-CCS Test and Interface
Processor (ETIP), a Cabinet Operator
Module (COM) and a Control Channel
Gateway (CCG).
Each GC receives ESF initiation
signals from the RPS and radiation
monitoring system via fiber-optic
receivers. All GCs perform system level
Nuclear Steam Supply System (NSSS)
and Balance of Plant (BOP) ESFAS
logics independently, so that they can
transfer the system level ESF actuation
signals to all LCs in the division. LCs
perform a component control logic using
system level ESF actuation signals from
GCs or component level control signals
from an operator, so that the output
control signals are assigned to individual
plant components. ETIP takes charge of
the passive and active test functions of the
ESF-CCS and the interfaces of the ESF-
CCS with other systems such as the RPS
and qualified indication and alarm system.
COM provides information about an
ESF actuation status, an ESF component
status and a module status. CCG supports
the interface between the ESF-CCS and
soft controllers in the main control room
or remote shutdown room.
Reactor Core Protection
System
The core protection calculator sys-
tem provides an on-line calculation of
