acads (08-006) covered keywords description supporting material 4.2.7.15
TRANSCRIPT
ACADs (08-006) Covered
Keywords
Description
Supporting Material
4.2.7.15
LP A LP B LP C
TO FEEDWATER LINEHDP A
HDP B
STEAM FLOW
FEEDWATER FLOW
DRAIN FLOW
3 355
5A 5B
6B6A
4A 4B
A
B
HDTHDT
CONDENSATE PUMPS
A
B
C
COND “A” COND “B” COND “C”
3A
1A
2A
3B
1B
2B
3C
1C
2C
HP
12 129 11911 12 129 11911 12 129 11911
7 7
2
OBJECTIVES
1. State the function of the Extraction Steam System.
2. Describe how Reactor Power will respond to the following:
a. Loss of feed water heatingb. Trip of a Heater Drain Pump
3. Describe why extraction steam stop valves and non-return check valves are used in extraction lines.
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OBJECTIVES
4. Describe the function of the “Heater Drain Pumps”
5. Explain why water induction into the main turbine is undesirable.
6
Extraction Steam Purpose
Provides steam to ALL 15 Feedwater heaters to heat the Condensate and Feedwater prior to entering the Steam Generators thus increasing plant efficiency.
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442°F
120°F
120ºF
184ºF
223ºF
288ºF
362ºF
401ºF
442ºF
8
LP A LP B LP C
TO FEEDWATER LINEHDP A
HDP B
STEAM FLOW
FEEDWATER FLOW
DRAIN FLOW
3 355
5A 5B
6B6A
4A 4B
A
B
HDTHDT
CONDENSATE PUMPS
A
B
C
COND “A” COND “B” COND “C”
3A
1A
2A
3B
1B
2B
3C
1C
2C
HP
12 129 11911 12 129 11911 12 129 11911
7 7
EXTRACTION STEAM – FEEDWATER FLOW – DRAIN FLOWRev 1
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EXTRACTION STEAMLP HEATERS1A, 2A, 3A
TO
CO
ND
EN
SER
LOW PRESSURE TURBINE
CONDENSER A
3A
2A
1A
91211
M
TO GLAND SEALINGSTEAM SYSTEM
Rev 110
FEEDWATER HEATERSTYPICAL OfHEATERS
1, 2, 3, and 5
EXTRACTION STEAM INLET
CondensateCondensateFlow
CondensateCondensateFlow
DRAIN INLET
DRAIN OUTLET
CONDENSATEINLET
CONDENSATEOUTLET
HIGH LEVELDUMP
Sub-cooled ZoneShell Side
654
HDT 321
CONDENSER 11
Extraction Steam
Drain to 5th StageFeedwater Heater
Drains Inlet
6th Stage Feedwater Heater
Feedwater
Inlet
FeedwaterOutlet
SubcooledZone
12
HP/LP TURBINE
MOV
REPRESENTIVE OF ALL FEEDWATER HEATEREXTRACTION STEAM LINES FOR
HEATERS 3, 4, 5, 6
Stop Valve
EXTRACTION STEAM STOP VALVE
Stop Check Valve
STOP CHECK VALVE
3,4,5,6
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Extraction Steam Stop Valves and Non-return valves are used to protect the main turbine from:
OverspeedWater entering turbine
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Water entering the main turbine is undesirable due to:
Erosion of the turbine bladesVibration of turbineBreakage of blades
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COUNTER-WEIGHT TEST SWITCH
CYLINDER AND PISTON
EXTRACTION STEAM STOP CHECK VALVE
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EXTRACTION STEAM STOP CHECK VALVE17
FW Heater Stage of Extraction
Extraction Steam Stop
Valve
Extraction Steam Non-
Return Valve
1 LP Turbine 12th Stage
NO NO
2 LP Turbine 11th Stage
NO NO
3 LP Turbine 9th Stage
YES YES
4 HPT to MSR Cross
Around Piping or
7th stage
YES YES
5 HP Turbine 5th Stage
YES YES
6 HP Turbine 3rd Stage
YES YES
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LP TURBINE
TTStop Check
ValveStopValve
MOV
9th 9th
3rd
I
LT
I
TT
LT
High-High
9th Stage Extraction Steam From LP Turbine to 3rd Heater
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LP TURBINE
Stop Check Valve
StopValve
MOV
7th 7th
4th LT
I
TT
HeaterDrain Tank
LT
I
LT
Hi-Hi
I
LT
High
7th Stage Extraction Steam From HP Turbine to 4th Heater(HP Turbine Exhaust Steam)
20
LP TURBINE
TTStop Check Valve
Stop Valve
MOV
9th 9th
3RD
I
LSH
High
I
LOW POINT DRAINS
Drain ManifoldCondenser
Drain ManifoldCondenser
LSH
DRAIN POT
ORIFICE
Drain ManifoldCondenser
I
EXTRACTION STEAM LINEDRAIN VALVE LOCATION
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LP TURBINE
Stop Valve
Stop Check Valve
Drain ManifoldCondenser
LSH
TT
I
DRAIN POT
ORIFICE
TT
Drain ManifoldCondenser
Drain ManifoldCondenser
LOW POINT DRAINS
MOV
9th 9th
3RD
I
LSH
I
Steam Line Drain Valves:
- Open on High HTR Level - Open on Turbine Trip - Open Stop Valve < 25% Open
High Drain Pot Level Only opens Associative Drain Valve
High Level
TT
TT < 25% Open
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LV-4257
LV-4244
LV-4241
LV-4256
LV-4236
LV-4233
LV-4247
LV-4239
LV-4245
LV-4237
LV-4242
LV-4234
LV-4246
LV-4243
LV-4240
LV-4238
LV-4235
LV- 4232
HTR 2A
HTR 1A
HTR 3A
HTR 2B
HTR 1B
HTR 3B
HTR 2C
HTR 1C
HTR 3C
FO
FO
CONDENSER "A"
CONDENSER “B"
CONDENSER “C"
FO FOFO
FO
FO
FO
FO
FO
FO
FO
FOFO
FO
FOFO
FO
FO
LP HEATER DRAINS
LP TURBINE A
LP TURBINE B
LP TURBINE C
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Heater Drains
The drainage from the various heat-exchanges (tube-side) after it transfers part of its heat energy to the Condensate & Feedwater flow stream is still at a relatively high energy so the water is pumped back into the Condensate & Feedwater System to also increase efficiency.
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LC LC
HEATER 6B
HEATER 5B
HEATER 4B
HEATER DRAIN TANK B
A
HEATER 6A
HEATER 5A
HEATER 4A
HEATER DRAIN TANK A
CB
CONDENSATE PUMPS DISCHARGE HEADER
COND“A”
COND“A”
COND“B”
COND“A”
COND“A”
COND“A”
COND“B”
COND“A”
MSR DMSR CMSR BMSR A
A DCBLC
LCLC
LC LC
LC LC
LCLC LC LC
LCLC
MSDT MSDTMSDT MSDT
RHDT RHDT RHDTRHDT
D
HTR 4ATUBESIDEOUTLET
HTR 4BTUBESIDEOUTLET
MARCMARC
COND“B”
COND“B”
DUMPDUMPDUMPDUMP
DUMP
DUMP DUMPDUMP DUMP DUMP
LC
LC
LCLC
LC
LC LC
HDP HDP
A B DUMP
HEATER DRAIN
SYSTEM
Rev 1
DUMP
MAIN STEAMMAIN STEAMMAIN STEAMMAIN STEAM
LC LC
HEATER 6B
HEATER 5B
HEATER 4B
HEATER DRAIN TANK B
A
HEATER 6A
HEATER 5A
HEATER 4A
HEATER DRAIN TANK A
CB
CONDENSATE PUMPS DISCHARGE HEADER
COND“A”
COND“A”
COND“B”
COND“A”
COND“A”
COND“A”
COND“B”
COND“A”
MSR DMSR CMSR BMSR A
A DCBLC
LCLC
LC LC
LC LC
LCLC LC LC
LCLC
MSDT MSDTMSDT MSDT
RHDT RHDT RHDTRHDT
D
HTR 4ATUBESIDEOUTLET
HTR 4BTUBESIDEOUTLET
MARCMARC
COND“B”
COND“B”
DUMPDUMPDUMPDUMP
DUMP
DUMP DUMPDUMP DUMP DUMP
LC
LC
LCLC
LC
LC LC
HDP HDP
A B DUMP
HEATER DRAIN
SYSTEM
Rev 1
DUMP
MAIN STEAMMAIN STEAMMAIN STEAMMAIN STEAMMAIN STEAMMAIN STEAMMAIN STEAMMAIN STEAM
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Reheater Drain Tank (RHDT)
• The Normal Level Control Valve modulates controlling drain flow to the 6th stage heater based on Reheater Drain Tank Level.
• If the level in the Reheater Drain Tank reaches the high level setpoint it will cause the “high level dump” valve to modulate open to dump the contents of the Reheater Drain Tank to the associated 4th stage heater.
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Moisture Separator Drain Tank (MSDT)
• The Normal Level Control Valve modulates controlling drain flow to the Heater Drain Tank based on the MSDT level.
• If the level in the MSDT reaches the high level setpoint it will cause the High Level Dump Valve to modulate open to dump the contents of the “MSDT” to the Condenser.
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Moisture Separator Reheater
• Rising level will cause a Main Turbine Trip on HIGH Level (2/3 Level Switches) on 1/4 Moisture Separator Reheaters.
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6A
LTC
LTB
LTA
LV4288FO
LV4284FO
FeedwaterHeater5A
LTA
LTB
I/P
LTC
MainCondenser
“A”
I/P
•RHDT normal drain Valves into 6A (C)•Scavenging Steam will align to Main Condenser•Extraction Steam: Isolation Valve (C) Non-Return Valve (C) Drain Valves (O)
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5A LTC
LTB
LTA
LV4282FO
LV4286FO
FeedwaterHeater4A
LTA
I/P
LTB
I/P
MainCondenser
“B”
LTC
•Normal drain from 6A (C) •Extraction Steam: Isolation Valve (C) Non-Return Valve (C) Drain Valves (C)
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4A
LTC
LTB
LTA
LV4331FC
LV4333FO
HDT“A”
LTA
LTC
I/P
LTB
I/P
LTC
•Normal drain valve from 5A (C)•MSDR normal drain valves (C) •Extraction Steam:Isolation ValveNon-Return ValveDrain Valves
MainCondenser
“A”
Between 4A and 5AFeedwater Heater
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HDT“A”
4A
LTC
LTB
LTA
Between 4A and 5AFeedwater Heater
LV4331FC
LV4333FO
LTA
LTC
I/P
LTB
I/P
LTC
Extraction Steam:•Isolation Valve•Non-Return Valve•Drain Valves
MainCondenser
“A”
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Heater Drain Pumps
Why do we need the Heater Drain Pumps?
During normal operation, the heater drain tank pump provides 1/3 of the flow requirements for NPSH to the main feedwater pumps and assists in preheating feedwater.
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How would Reactor Power respond to the trip of a Heater Drain Pump with the Reactor at 100% power ?
A. Stay the same. B. Increase. C. Decrease.
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√
Heater Drain System Malfunction
• Malfunction of feedwater heater drain system could have a significant impact on plant operation.
• Plant efficiency would be reduced because
• Loss of feedwater heating capability
• May exceed reactor core limits:
– Reactor Power– RCS Delta Temperature Limits– RCS Pressure limits
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SUMMARY• Extraction Steam, Feedwater Heaters and Heater Drain
systems are important to the preheating of feedwater prior to flowing into steam generator and for improving secondary efficiency.
• A loss of any feedwater heating causes reactor power to increase due to the decrease in RCS temperature.
• Not maintaining proper feedwater heater level also causes a decrease in secondary efficiency which affects reactor power.
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Objectives Review
1. State the function of the Extraction Steam System.
2. Describe how Reactor Power will respond to the following:
a. Loss of feed water heatingb. Trip of a Heater Drain Pump
3. Describe why extraction steam stop valves and non-return check valves are used in extraction lines.
39
Objectives Review
4. Describe the function of the “Heater Drain Pumps”
5. Explain why water induction into the main turbine is undesirable.
40