Description of Secondary circuit for Rooppur Nuclear Power Plant

1. Presented By
Nusrat Karim
Assistant Manager
Nuclear Power Company Bangladesh Limited (NPCBL)
Email- nusrat.karim205@rooppurnpp.gov.bd
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 1
Overview of Design Features of Turbine Plant
and Secondary Circuit Equipment of
Rooppur NPP

2. TRAINING OBJECTIVES
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 2
Terminal Training Objective
Explain Design Features of Turbine Plant and Secondary Circuit
Equipment of Rooppur NPP
Enabling Training Objectives
 State the purpose and structure of K-1200-6.8/50 Steam Turbine.
 Mention the basic operating parameters of Secondary circuit.
 Describe the purpose of Moisture Separator Re-heater (MSR).
 Explain why Deaerator is needed.
 Explain the purpose of CEP, FEP & AFEP.
 List the factors affecting turbine plant efficiency.

3. BASIC NPP LAYOUT
3

4. PURPOSE OF TURBINE К-1200-6.8/50
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 4
Steam Turbine K-1200-6.8/50 is designed for converting thermal power of
the steam generated in steam generators into mechanical power for rotation of
rotor.
K-Condenser Type
1200-Electrical Power, MW
50-Frequency, Hz
6.8-Pressure, MPa
K-1200-6.8/50

5. HEAT BALANCE DIAGRAM OF SECONDARY CIRCUIT
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 5

6. SIMPLIFIED DIAGRAM OF SECONDARY CIRCUIT
SG HPC MSR LPC
Condenser
Cooling
Tower
CEP-1
LPH-1
SSC
UDP
LPH-4 LPH-3 LPH-2
CEP-2
Deaerator
AFEP
FEP
HPH-5
HPH-6
SHW
CHTP
HW-I HW-II
SRP

7. SIMPLIFIED DIAGRAM OF SECONDARY CIRCUIT
SG
Generates dry
saturated steam
Conversion of thermal
energy to mechanical
energy
Moisture
separation
& reheating
Condensate
the steam
UDP
CEP-1
CEP-2
LPH-1
LPH-2
LPH-3
LPH-4
SSC
HPH-6 HPH-5
To supply main
condensate from
condenser to
LPH-2
Maintain
condensate
quality
Increase condensate
temperature by steam
from turbine extractions
To supply main
condensate to
deaerator
To remove 𝑂2
and other
corrosive gases
Heating of
feed water
FEP AFEP
Supply
FW to SG

8. TURBINE BASIC OPERATING PARAMETERS IN THE RATED MODE
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 8
Parameter Value
Electric power 1195.4 MW
Main steam rated flow (with account of steam flow to intermediate
superheater) 6461.5 t/h
Rated parameters of main steam:
 Pressure
 Temperature
 Humidity
6.8 MPa
283.8 ºС
0.5 %
Parameters after steam reheating:
 Pressure
 Temperature
0.579 MPa
270.5 ºС
Cooling water design temperature 20 ⁰С
Rated absolute pressure of steam in condenser 5.15 kPa
Rated mass flow of cooling water to the condensers 143,700 t/h
Rated absolute pressure of steam in deaerator 0.81 MPa
Feedwater temperature 227 ⁰С

9. STEAM TURBINE К-1200-6,8/50
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 9

10. TURBINE STRUCTURE
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 10
 High Pressure Cylinder (HPC)
 Four Low Pressure Cylinders (LPC)
 Ten turbine support bearings and one support bearing of
the generator
 Thrust bearing combined with support bearing
 Shaft turning gear

11. KEY FEATURES OF TURBINE
 1 HPC and 4 LPC
 Single Molded shaft
 Symmetrical butterfly shape
 Self Sealing
 High RPM (3000).
 TiN layer on the last stage blade of LPC.
 Inlet pipes are situated under the turbine body.

12. HPC CASINGS OF TURBINE К-1200-6,8/50
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 12
Steam from SG
To MSR To MSR

13. LPC CASINGS OF TURBINE К-1200-6,8/50
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 13

14. EXTRACTION LINES
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 14
Total SEVEN extraction lines are present in steam turbine,
FOUR of them from HPC and rest THREE from LPC.

15. Purpose of Moisture Separator Re-Heater
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 15
1st Stage
Moisture Removal
2nd Stage
Heating up to 213° C
3rd Stage
Heating up to 270° C
• By removing
moisture increase
the life time of
LPC.
• Heating the
steam in two
stages to increase
the efficiency

16. Turbine Hall
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 16
LPC-1 LPC-4
LPC-3
LPC-2
MSR-1 MSR-3
MSR-4
MSR-2
HPC

17. Turbine Hall (UMA building)
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 17

18. CONDENSER
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 18
Gravitational separation of liquid and vapor plays an important role in ensuring the operation
of condenser. In power plant condensers, steam usually condenses in the annulus, and
cooling water flows through horizontal pipes. In process equipment, condensation usually
occurs inside the pipes. In these cases, the pipes are usually vertical.

19. CONDENSATE ELECTRIC PUMP (CEP-1)
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 19
Purpose of CEP-1 &
CEP-2
 Supply condensate
from condenser to
Deaerator.
 Condensate supply to
various auxiliary
systems.
 CEP-1 motor
800KW, CEP-2
motor 2000KW

20. CONDENSATE ELECTRIC PUMP (CEP-2)
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 20

21. REGENRATION SYSTEMS
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 21
To increase the condensate & feed water temperature by
using steam from the turbine extraction lines.
There are FOUR low pressure heaters LPH-1, LPH-2, LPH-
3 & LPH-4 AND TWO high pressure heaters HPH-5, HPH-
6 are used.
LPH-1

22. PURPOSE OF DEAERATOR
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 22
 To remove corrosion active
and non condensable gases
like O2, CO2 etc.
 Create suction for FEP and
AFEP
 Increase feed water
temperature
 To supply sealing steam

23. FEED ELECTRIC PUMP (FEP)
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 23
Purpose
• initial SG filling up with
feed-water
• water supply to the SG in
NO modes
• maintaining the water level
in the SGs
• termination of feed-water
supply if the SG is full or a
damaged SG.
• FEP motor capacity 6300KW

24. FEP STRUCTURE
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 24

25. AUXILIARY FEED ELECTRIC PUMP (AFEP)
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 25
Purpose
• Supply feed water to
SG in normal
operation, abnormal
operation and in case
of failures.
• Heating up the
deaerator
• Preoperational de-
aeration of Feed water
• AFEP motor 800kW

26. MAIN COOLING WATER SYSTEM
• To remove heat from turbine condenser and liquid ring
vacuum pump
• 4 pumps are used each motor capacity 4000kw

27. FACTORS AFFECTING TURBINE PLANT EFFICIENCY
Turbine plant efficiency is affected for the following reasons:
1. Cooling capacity of condenser. ( Plant efficiency increases in lower atmospheric
temperature )
2. Regeneration system.
3. Dry saturated steam. ( 1% plant efficiency is decreased for every 1% moisture
increase in main steam.)

28. TRAINING OBJECTIVES
Nuclear Power Plant Company Bangladesh Limited (NPCBL) 28
Terminal Training Objective
Explain Design Features of Turbine Plant and Secondary Circuit
Equipment of Rooppur NPP.
Enabling Training Objectives
 State the purpose and structure of K-1200-6.8/50 Steam Turbine.
 Mention the basic operating parameters of Secondary circuit.
 Describe the purpose of Moisture Separator Re-heater (MSR).
 Explain why Deaerator is needed.
 Explain the purpose of CEP, FEP & AFEP.
 List the factors affecting turbine plant efficiency.

29. Nuclear Power Plant Company Bangladesh Limited (NPCBL) 29