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Contents
• Introduction
• Reactor Coolant System
• Reactor Auxiliary Systems
- Chemical and Volume Control System
- Engineering Safety Features
• Safety Injection System
• Shutdown Cooling System
• Containment System
• Safety Depressurization System
• Main Steam and Main Feedwater System
Introduction
Basic PWR Steam Cycle
STEAM
GENERATOR
RCP
REACTOR
CONTAINMENT
TURBINE
CONDENSER
FEEDWATER PUMP
SEA
WATER
ELECTRIC
GENERATOR
BASIC PWR STEAM CYCLE
• A pressurized water reactor(PWR) system utilizes,
basically, two separate heat transfer loops to
accomplish the production of steam for turbine-
generator operation.
– primary system (loop)
– secondary system (loop)
• Primary System
– Reactor vessel, Reactor coolant pumps, Pressurizer, Steam
generator, and Interconnecting piping
• Secondary System
– Shell side of the steam generator, High and low pressure
turbines, Main electrical generator, Main condenser, Condensate
and feed pumps, and Interconnecting piping
General Arrangement
No Building Name
1 Containment Building
2 Auxiliary Building
3 Compound Building
4 Fuel Building
5 Turbine Building
①
② ③
④
⑤
④
⑤
C/B
PA
/B
SA
/B
AC
/B
F/B
T/B
R/B
INT
AK
E
②
Intake
Classification of NPP
• Nuclear Power Plant (NPP)
– NSSS (Nuclear Steam Supply System)
– BOP (Balance of Plant)
– T/G (Turbine Generator)
Nuclear Island
Turbine Island
OPR 1000
• OPR 1000 : Optimized Power Reactor 1000
• Reactor Type : PWR
• Reactor Capacity : 2,825 MWt (1,050MWe)
• Plant Life Time : 40 Years
• Seismic Design
– SSE 0.2g, OBE 0.1g
• Refueling Interval
– 18 Months
• Safety Goals
– CDF 10-4 /reactor year
– CFF 10-5 /year
• Plant availability : 88%
Ulchin Nuclear Power Plants
OPR 1000 Plant Layout (3-D View)
Containment
Turbine Building
Fuel Building
Aux. Building
OPR 1000 Process Systems
Main SteamSafety Valve
AtmosphericDump Valve
Containment
Containment Spray Header
PressurizerSafety Valve
RDT
SafetyDepressurizationSystem
Pressurizer
Control Rod
ReactorVessel
SteamGenerator 2
SafetyInjectionTank
SteamGenerator 1
In-Core Instrument
Train A
Train B
Filter
Core
RefuelingWaterTank
ReactorDrainTank
IonExchanger
VolumeControlTank
ContainmentRecirculationSump
RegenerativeHeat Exchanger
ChargingPump
ChargingControl Valve
AuxiliaryChargingPump
LetdownHeat Exchanger
LetdownOrifice
BoricAcidMake-upPump
Low PressureSafety InjectionPump
High PressureSafety InjectionPump
ContainmentSpray Pump
ContainmentSpray
Hot Leg
Cold Leg
Shutdown CoolingHeat Exchanger
ReheaterDrainTank
ReheaterDrainTank Separator
DrainTank
HP Heater 7 HP Heater 5 HP Heater 5
Stop ValveControl Valve
Intercept ValveIntermediate Valve
HP Heater 7
LPHeater 1
FeedwaterPump
FeedwaterBoosterPump
LP ExtractionSteam
HP ExtractionSteam
Moisture SeparatorReheater
2nd Stage Reheater
1st Stage Reheater
HPExtractionSteam
Turbine Bypassto Condenser
HP TurbineLP Turbine
(3EA) Generator
Condenser
Sea WaterFrom Intake
Sea Waterto Discharge Duct
CondensatePump
Hot Well
DeaeratorStorageTank
Deaerator
DeaeratorStorage TankLevel ControlValve
LP ExtractionSteam
LPExtractionSteam
EconomizerFeedwaterControl Valve
DowncomerFeedwaterControl Valve
Main SteamIsolation Valve
CC
LPHeater 2
LPHeater 3
HP Heater 6
HP Heater 5
ReactorCoolantPump
RCS
CVCS
SIS (ECCS) - HPSI
- LPSI
- SIT (Accumulator)
MS&MFS Containment
SDCS (RHRS)
Reactor Coolant System
Reactor Coolant System (RCS)
• Functions
– Transfer Heat generated
from Reactor to Steam
Generator
– 2nd Barrier of Fission
product Release to
Environment
• Main components
– one reactor vessel
– two steam generators
– four reactor coolant pumps
– one pressurizer
– RCS Piping
– interconnecting pipes to
auxiliary systems such as
CVCS, SCS, and SIS
1B
2A
2B
Steam
Generator 1
Steam
Generator 2
1A
Reactor Vessel
Pressurizer
Reactor
Coolant
Pump
Reactor
Coolant
Pump
RCS Schematic Flow Diagram
Main SteamSafety Valve
AtmosphericDump Valve
Containment
Containment Spray Header
PressurizerSafety Valve
RDT
SafetyDepressurizationSystem
Pressurizer
Control Rod
ReactorVessel
SteamGenerator 2
SafetyInjectionTank
SteamGenerator 1
In-Core Instrument
Train A
Train B
Filter
Core
RefuelingWaterTank
ReactorDrainTank
IonExchanger
VolumeControlTank
ContainmentRecirculationSump
RegenerativeHeat Exchanger
ChargingPump
ChargingControl Valve
AuxiliaryChargingPump
LetdownHeat Exchanger
LetdownOrifice
BoricAcidMake-upPump
Low PressureSafety InjectionPump
High PressureSafety InjectionPump
ContainmentSpray Pump
ContainmentSpray
Hot Leg
Cold Leg
Shutdown CoolingHeat Exchanger
ReheaterDrainTank
ReheaterDrainTank Separator
DrainTank
HP Heater 7 HP Heater 5 HP Heater 5
Stop ValveControl Valve
Intercept ValveIntermediate Valve
HP Heater 7
LPHeater 1
FeedwaterPump
FeedwaterBoosterPump
LP ExtractionSteam
HP ExtractionSteam
Moisture SeparatorReheater
2nd Stage Reheater
1st Stage Reheater
HPExtractionSteam
Turbine Bypassto Condenser
HP TurbineLP Turbine
(3EA) Generator
Condenser
Sea WaterFrom Intake
Sea Waterto Discharge Duct
CondensatePump
Hot Well
DeaeratorStorageTank
Deaerator
DeaeratorStorage TankLevel ControlValve
LP ExtractionSteam
LPExtractionSteam
EconomizerFeedwaterControl Valve
DowncomerFeedwaterControl Valve
Main SteamIsolation Valve
CC
LPHeater 2
LPHeater 3
HP Heater 6
HP Heater 5
ReactorCoolantPump
RCS Arrangement
Cross Section View Top View
원자로
원자로
RCP
RCP
RCP
RCP
가압기
증기
발생기
Westinghouse RCS Arrangements
Two Loop (600MWe) Three Loop (1000MWe)
VVER RCS Arrangement
Four Loop (1000MWe)
Reactor Vessel
• Reactor Pressure Vessel
– A large cylindrical vessel which
serves to contain and support the
reactor core and vessel internals
– Material : carbon molybdenum
steel internally coated with
stainless steel
• Reactor Internals
– Reactor Vessel Head Assembly
– Upper Guide Structure
– Core Support Barrel Assembly
– Lower Support Structure
원자로 제어봉구동장치 (CEDM)
원자로 HEAD(RV CLOSURE HEAD)
상부구조물(UPPER GUIDE
STRUCTURE; UGS)
원자로 출구노즐(OUTLET NOZZLE)
핵연료 지지용기(CORE SUPPRTBARREL; CSB)
하부구조물(LOWER SUPPORTSTRUCTURE; LSS)
원자로 입구노즐(INLET NOZZLE)
핵연료 (CORE)
CEDM
Reactor
Head
Upper
Guide
Structure
Outlet
Nozzle
Inlet
Nozzle
Nuclear
Fuel
Core Support
Barrel
Lower Support
Structure
Flow Path – Reactor Vessel
Bypass Flow
Cold Leg Hot Leg
Reactor Internals
Core Support Structure
Snubber Assembly
Lower Support Structure Upper Support Stucture
Alignment Key
Upper Guide Structure Core Barrel
O-ring
RCS Component Supports
Reactor Vessel
Support Structure RCP Support
Structure S/G Support
Structure
Pressurizer
Support
Structure
Core and Fuel Assembly
• Reactor Core – Fuel assembly
– Control rod • Ag-In-Cd or B4C
• Design data – Total core heat output : 2815 MWt
– Electric Power : 1050MWe
– Number of fuel assemblies : 177
– Fuel length : 150in.
– Equivalent core diameter : 123 inches
Nuclear Fuel
UO2 Power
UO2 Pellet
Cladding
Fuel Assembly Reactor Fuel Rod
Reactor Core
UEF
LEF
SG
Reactor Coolant Pump
• Motor-Driven, 1 stage Vertical
Centrifugal Pump
• Function
– Circulate reactor coolant during
normal operation
– Heat up reactor coolant system
during startup operation
• Sub Components
– Pump Part
• Casing, Impeller, Diffuse, Seal
housing
– Shaft Seal System
– Electrical Motor
RCP Operation Point Determination
Total
System
Resistance
SG
Piping
Reactor Vessel
HEAD, H
FLOW, Q
RCP
Characteristic Curve
Ho
Qo
System Operating Point
H = K Q2
2gA2
RCS Flow Rate Determination
HEAD VS. FLOW RATE
HEAD
(Feet)
System Flow Rate, % of Qdesign
(EOL)
B.E., 8% SG Tubes Plugged
2psi Core Crud
(EOL)
B.E. + 2
(BOL)
B.E., No SG Tubes Plugged
Clean Core
(BOL)
B.E. - 2
RCP Characteristic Curve
Minimum
Operating
Point – Pump
Rated Head
103.5% 108%
Available
Flow Band
Hydrodynamic Shaft Seal
COUPLING
3RD SEAL
2ND SEAL
P4
P3
P2
P1
1ST SEAL
AUXILIARY
IMPELLER
CYCLONE
FILTER
JOURNAL BEARING INJECTION WATER
IMPELLER
CONTROLLED LEAKAGE
FL
OW
RE
ST
RIC
TO
R
RCP
COOLING WATER INTERFACES
SUCTION
PUMP CASING
SEAL INJECTION
HP COOLER
COOLING
WATER
MOTOR CASING
COOLING WATER
SEAL
COOLER
DISCHARGE
COOLING WATER
COOLING WATER
AIR
COOLER
OIL
COOLER
Steam Generator
• Recirculation Heat Exchanger
– Vertical, inverse U-type with integral economizer
• Function
– Interface between primary system
and secondary system
– Produce steam to Turbine Generator
• Sub Components
– Evaporator
• U-Tube : Inconel 690 (Ni-Cr-Fe Alloy)
• Reactor coolant inside, Feedwater
outside of the tube
– Steam Drum
• Centrifugal Separators, Steam Dryers
– Economizer
Steam Dryers
Centrifugal Separators
U-Tube
PWR Steam Generators
Once Through
Steam Generator Recirculating
Steam Generator Recirculating Steam Generator
with a Pre-heater
PWR Steam Generators
VVER-440 Steam Generator
VVER-1000 Steam Generator
• Horizontal Type
SG Flow Path and Economizer
FEEDWATER
INLET
FLOW DISTRIBUTION PLATE
EGG CRATE
DOWNCOMER FLOW
STAY CYLINDER
Economizer TH TC
Function of the Economizer Increase Plant Thermal Efficient
Increase Steam Pressure
Decrease SG Heat Transfer Area
Thermal Effectiveness of
Economizer Concept
T P,HOT
T P,COLD TS
TFW TS
SG INLET SG OUTLET
TE
MP
ER
AT
UR
E
Pinch Point
Pinch Point
Pressurizer
• Function
– Control RCS Pressure
• Maintain reactor coolant at
subcooled state
– Regulate RCS Water Volume
• Compensate reactor coolant
volume change during reactor
transient operation
• Sub Components
– Heaters
– Main and Aux. Spray Nozzle Heaters
Spray Nozzle
Pressurizer Safety Valve (PSV)
Optimization of PSV Design
FLOATING WASHERLIFT STOP
SUPPORT PLATE
INLET NOZZLE
OUTLET NOZZLE
Design Point
Normalized to Design Capacity
Inlet Nozzle
Outlet
Nozzle
Spring Loaded Safety Valve
Control Element Drive Mechanism
(CEDM)
• Magnetic Jack Type
• Function
– Equipment for inserting and
withdrawing control assembly into
reactor core
• Reactor Normal Operation
– Maintain the position of control
assembly as programmed
• Reactor Shutdown/Loss of Electricity
– Insert control rod into reactor core
by gravity
Cable Connector
Internal Pr Housing
Operation Coil Assembly
Control Rod Driving Shaft
Internal latch Assembly
RCS Instrumentation
• Process Instrumentations
– Temperature, Pressure, Level,
Vibration, etc.
– Monitoring, Control, Protection
• Nuclear Instrumentation
– In-core and Ex-core Instrumentation
RCS H/L #1
RCS H/L #2
Start-up CH #2
Start-up CH #1
Safety CH #1
Safety CH #4
Safety CH #3
Safety CH #2
Control CH #2
Control CH #1
Fuel
Ex-Core Instrumentation
In-Core Instrumentations (45)
Reactor Control System
Power Control (Reactivity Control)
RRS
CEDMCS
RPCS
PPCS PLCS
SBCS
FWCS
Steam Bypass Control
Feed Water Flow Control
Pressurizer
Level Control
PressurizerP
ressure
Control
Reactor
Reactor Control Program
Reactor Power (%) Reactor Power (%)
RCS Temperature Control Program Secondary System Pressure
Control Program
Reactor Operation
• Plant Startup
– The series of operation which bring the plant from subcritical cold
shutdown state to hot standby condition
– Filling RCS, Pressurizing, Venting, Heat up, Reactor Startup
• Hot Standby
– Zero power operation with the reactor conditions of the same as
the power operation mode
• Power Operation
– Operation of the reactor at the power level of 15 to 100%
– Reactor is automatically controlled by control systems
• Reactor Shutdown
– The series of operations which bring the RCS from hot standby
condition to a cold shutdown condition in preparation for refueling
or other maintenance operation
OPERATIONAL MODES
Mode Reactivity, Keff
Avg. Coolant
Temperature, oF
% Rated
Thermal Power
1. Power Operation > 0.99 > 500 > 5%
2. Start Up > 0.99 > 500 < 5%
3. Hot Standby < 0.99 > 500 0
4. Hot Shutdown < 0.99 210 < Tavg < 500 0
5. Cold Shutdown < 0.99 < 210 0
6. Refueling < 0.95 < 135 0
P-T Limit Curve
• The object of the P-T limit
curves is to prevent
operation in conditions
which would lead to brittle
characteristics of the
steels.
• RTNDT (Reference
Temperature of Nil
Ductility Temperature)
• Max. RTNDT: 60oF
PR
ES
SU
RIZ
ER
PR
ES
SU
RE
, P
SIA
REACTOR COOLANT TEMPERATURE, oF
Lowest Service Temperature
Inservice Test
System Cooldown
at 100o/Hr
System Heatup
at 100o/Hr
Core Critical
Operation
SDC Operation
RCS and Interfacing System
Steam
Generator
No. 1
Reactor
Vessel
Steam
Generator
No. 2
PRESSURIZER
LOOP 2LOOP 1
Shutdown
Cooling
Shutdown
Cooling
LOOP 2B
LOOP 2AMain
Steam
RCP 2A
RCP 2B
Letdown
(CVCS)
LOOP 1A
RCP 1B
RCP 1A
Main
Steam LOOP 1B
RCGVS
Surge Line
Charging Line
(CVCS)
Safety Valves
(3)Aux. Spray
Reactor Drain Tank (RDT)
Reactor Coolant Gas Vent
System (RCGVS)
Safety Injection
PZR Spray
Control Valves
Containment
Rupture
Disk (2)
SDS Globe & Gate
Valves (2)
CVCS
CVCS : Chemistry and Volume Control System
Chemistry and
Volume Control System (CVCS)
• Function
– Maintain Reactor Coolant Inventory
– Maintain Chemistry of the Reactor Coolant
– Provide Reactivity Compensation (Dilution & Boration)
– Provide seal water to RCP
– Supply cold water to Pressurizer Auxiliary Spray System
– Periodically checking the operability of SIS check valves
• Sub-Systems
– Letdown System
– Charging System
– Makeup System
– Chemical Addition System
– Boron Recycle System
Schematic Flow Diagram of thed
CVCS
Regeneration HX RCP Seal
Aux.
Spray
Letdown
Charging VCT
RWST
MWT
IX
Filter
IX
Letdown HX
Orifice IX
Charging Pump
Aux. Charging Pump
BAT
Containment Aux. Building
CAT
Makeup Pump
ESF
ESF : Engineered Safety Features
Safety Aspects of
Nuclear Power Plant
• Radioactive materials are
produced during nuclear
reaction
- possibility of radioactive
material release to the
environment
• Decay Heat after Reactor
Shutdown
– Right after Rx. shutdown : 7%
– About 1 hour : 1.1%
– About 1 month : 0.1%
Energy
(~200MeV)
+
neutron
235U
+
+ + + + + + +
+
Fission Products
(radio active materials)
Perc
ent
Pow
er
Time (sec)
Fission Products
(radio active materials)
Defense in Depth – Multiple Barriers
First barrier Fuel Pellet
Second barrier Fuel Cladding
Third barrier (25cm Reactor Vessel)
Fourth barrier(6cm steel liner)
Fifth barrier(120cm steel concrete)
Multiple Level of Protection
Stage Objects and Function Key Means
1 Stage • Maintain Normal Power Operation State
• Quality Assurance
• High Quality Maintenance
• Safety Culture
2 Stage • Preventing Accident • Control and Monitoring System
• Reactor Protection System
3 Stage • Accident Mitigation • Engineered Safety Features
• Emergency Operation Procedure
4 Stage • Severe Accident Mitigation • Containment
• Accident Management Plan
5 Stage • Off-site Emergency Response • EAB, EPZ, Emergency Plan
Engineered Safety Features (ESF)
• Function : Mitigates the consequences of design basis accidents
(DBA) by minimizing fuel damage and radioactivity release
– Prevention of progression of DBA into severe accidents
• Safety Injection System (SIS)
– High Pressure Safety Injection (HPSI)
– Low Pressure Safety Injection (LPSI)
– Safety Injection Tank (SIT)
• Shutdown Cooling System (SDCS)
• Aux. Feedwater System (AFWS)
– Atmospheric Dump Valve (ADV)
• Containment System
– Containment
– Containment Spray System (CSS)
• Safety Depressurization System (SDS)
ADV
AFWS
(EFWS)
SIS
(ECCS)
CSS
SDS
PSV
Containment
SDCS
(RHRS)
Safety Injection System (SIS)
• Function
– Supply borated water during LOCA
– Remove decay heat and long term cooling after LOCA
– Supply borated water during RCS overcooling event such as Main
Steam Line Break accident
– Feed and Bleed operation with Safety Depressurization System
• Design Characteristics
– Separate High and Low Pressure Safety Injection
– Automatic actuation upon safety injection signal
– Adopt Single Active Component Failure
– 100% physical independency
– Emergency Power Supply
• HPSI (High Pressure)
• LPSI (Low Pressure)
• SIT (Accumulator)
Schematic Diagram of SIS
Loop1 Hot Leg
Loop2 Hot Leg
Loop1 Cold Leg
SIT
HPSI Pump 2
Refueling Water
Tank
HPSI Pump 1
LPSI Pump 1
LPSI Pump 2
Shutdown Cooling
Heat Exchanger
Containment Recirculation Sump
SIT
SIT
SIT
Loop2 Cold Leg
shutdown cooling system (SCS)
• FUNCTION
– Remove core decay heat during shutdown
• reduce the temperature of the RCS in post shutdown periods from normal
operating temperature to the refueling temperature in conjunction with main
steam and main feedwater system
• Remove decay heat so that RCS should maintain the cold shutdown condition
during reactor shutdown
– Provides low temperature overpressure protection for RCS
– Operate under post accident conditions for cooldown and long term cooling
• Cooldown the RCS following a design basis accident with the SG atmospheric
steam release capacity and the auxiliary feedwater system
• Design Characteristics
– Low pressure safety injection pump is used as the shutdown cooling pump
– The SCS heat exchangers are used with the containment spray system to
cool the containment spray water
Shutdown Cooling System (SCS)
Shutdown
Cooling HX
High Pressure Safety
Injection Pump
LOOP 2
Cold Leg
LOOP 2
Hot Leg
LOOP 1
Cold Leg
LOOP 1
Hot Leg
Low Pressure Safety
Injection Pump
Auxiliary Feedwater System (AFWS)
• Function
– Provide adequate cooling
water to the SG in event of a
loss of main feedwater
• Design Characteristics
– Each auxiliary feedwater
subsystem aligned to feed its
respective SG
– provide enough feedwater to
cool the unit down safely to
the temperature at which the
shutdown cooling system can
be utilized
Auxiliary Feedwater System
(Emergency Feedwater System)
Containment System
• FUNCTION
– Completely encloses the entire reactor and reactor coolant system
– Essentially no leakage of radioactive materials to the environment
– The structure provides biological shielding for both normal and
design basis accident situations
• Design Basis
– Hypothetical loss-of-coolant accidents (LOCA) and
– Secondary system pipe breaks
• Containment sub-systems
– Containment Building
– Containment Heat Removal Systems
– Containment Isolation System
– Combustible Gas Control System
– Containment Ventilation System
Containment Building
• A large dry containment
• Containment structure
– A reinforced concrete base slab
– A pre-stressed concrete cylindrical
shell
– Hemispherical dome
– A reinforced concrete internal
structure
• Leak tight
– The inside face of the slab, shell, and
dome is lined with a leak tight carbon
steel liner
• Aircraft Crash
– Maintain the containment integrity
Dome
Steel Liner
Steel Liner
Steel Liner
Base MAT Sump
Containment heat removal systems
• Containment heat removal systems
– Containment Fan Cooling System
– Containment Spray System
• Containment Fan Cooling System
– Non safety system
– Remove containment heat during post accident period
• Containment Spray System
– Limit the peak pressure in the containment to less then design
pressure during LOCA or a steam break accident inside
containment.
– Removes iodine released on a break of the fuel cladding
following a loss of coolant accident
Schematic Diagram of
the Containment Spray System
Safety Depressurization System
(SDS)
• Function
– SDS is designed to provide a manual means of rapidly depressurizing
the RCS for the highly unlikely event of a total loss of feedwater
(TLOFW)
• Design Characteristics
– Safety system design
– Remote manual operation
– Prevent miss operation by
reactor operators
• Components
– SDS VALVES
• 1 globe and 1gate valve
– Rupture Disk SDS schematic Flow Diagram PZR
RDT
MS&MFWS
MS&MFWS :
Main Steam and Main Feedwater System
Main Steam and
Main Feedwater System
• Main Steam System
– Deliver steam from the secondary side of the NSSS steam generators
to the turbine generator
– Supply auxiliary steam to the following components
• Feedwater pump turbines, auxiliary feedwater pump turbines, the second
stage reheater of the moisture separator reheater (MSR), Turbine Steam
Seal System, Auxiliary Steam System and Process Sampling System
• Main Feedwater System
– Deliver condensate from hotwell to the steam generator
– Condensate System
• from hotwell to the deaerator storage tank
– Feedwater System
• from the deaerator storage tank to the steam generators
• On viewpoint of Energy Conversion
– Reactor Coolant System : Primary System
– Main Steam and Main Feedwater System : Secondary System
Schematic Diagram of
the MS&MFWS
CONDENSER
POLISHER
S/G WET LAYUP RECIRCULATION
LP TBN
CONDENSATE
PUMPS
GRAND SEAL/
AIR EJECTORS
HP
DRAINS
DEAERATOR
STORAGE
TANK(2)
STARTUP
FW PUMP DEAERATOR
2
2
6
3
1
4
S SS
S
CHEM
ADD
5
4 3
HP FW
HEATERS(2)
LP FW
HEATERS(3)
FW PUMPS
TBN(2),MTR(1)
CHEM
ADD
CHEM
ADD
2
STARTUP FEEDWATER RECIRCULATION
1
2
1
1
1
1
1 1
2
2
4
MAKEUP
2
CONDENSATE
STORAGE
TANK 5
AUXILIARY
FEED PUMP
4
MSRHHP TBN
6 2 11 2
1
1
BLOWDOWN
TREATMENT
3
3
4
1 - STEAM
2 - FEED/CONDENSATE
3 - S/G
4 - MAKEUP
S - SAMPLING POINT
S/G
3
S
HP TBN
LP TBN
Condenser
MSRH
Condensate
Pump Startup
Pump
FW Pump
Auxiliary
FW Pump
Steam
Generator S/G Wet Layup Recirculation
Startup Feedwater Recirculation
Main Steam System
Condensate System
Feedwater System
Power Cycle
• The MS&MFS converts the heat energy generated by the nuclear
reactor into electrical energy
• Basic Steam Cycle : Reheat and Regenerative Cycle
– 1 reheater, 1 open feedwater heater and 6 closed feedwater heater
Turbine Generator
• The turbine generator converts the energy of the steam produced in
the steam generators into mechanical shaft power and then into
electrical energy
• The turbine generator consists of a double-flow, high-pressure
turbine and three double-flow low pressure turbines driving a direct-
coupled generator
Moisture Separator/Reheater
• To increase the quality of steam from the high pressure turbine
before entering the low pressure turbine
• Reheating the steam from the high pressure turbine after removing
moisture to increase thermal power efficiency
2nd Stage Reheater
1st Stage Reheater
Moisture Separator Impingement
Plate
Main Condenser
• Condenser is a kind of heat exchanger which condensates steam
expanded from turbine
• It can also remove non-condensable gas contained in the expanded
steam
• Operating Pressure and Temperature : 0.05 bar, 33oC
Condensate and Feedwater Pump
• Condensate Pump (three 50% capacity motor-driven)
– Deliver condensate from the condenser hotwell to the deaerator
• Feedwater booster pumps (three 50% capacity motor-driven)
– deliver condensate from the deaerator storage tank to the suction of the
main feedwater pumps
• Main feedwater pumps (three 50% capacity turbine-driven)
– deliver feedwater to steam generator
• Startup feedwater pump (one motor-driven)
– provides feedwater during shutdown and startup
Pre Heating
228°C
33°C
Extraction Steam
LP A LP B LP C
TO FEEDWATER LINE HDP A
HDP B
STEAM FLOW
FEEDWATER FLOW
DRAIN FLOW
3 3 5 5
5A 5B
6B 6A
4A 4B
A
B
HDT HDT
CONDENSATE
PUMPS
A
B
C
COND “A” COND “B” COND “C”
3A
1A
2A
3B
1B
2B
3C
1C
2C
HP
12 12 9 11 9 11 12 12 9 11 9 11 12 12 9 11 9 11
7 7
Low Pressure Feedwater Heaters
EXTRACTION STEAM INLET
DRAIN INLET
DRAIN OUTLET
CONDENSATE INLET
CONDENSATE OUTLET
HIGH LEVEL DUMP
Sub-cooled Zone Shell Side
High Pressure Feedwater Heaters
EXTRACTION STEAM INLET
DRAIN INLET
Drain to 5th stage Feedwater Heater
FEEDWATER INLET
FEEDWATER OUTLET
Extraction Steam Line
HP/LP TURBINE
MOV
Stop Valve
Stop Check Valve
FEEDWATER HEATER
Heater Drain System
Deaerator
• One deaerator and two deaerator storage tanks are installed to
remove oxygen
Circulating Water System
• Provides cooling seawater to the main condenser for the removal of
the waste heat to the sea as a heat sink
• Chlorination of the circulating water and condenser tube cleaning
– to control biological growth inside the condenser tubes and the growth
of marine organisms in the intake structure
– to remove bio-fouling, sediment, corrosion products, and scaling
Thank you
