ACADs (08-006) Covered Keywords Description Supporting Material

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 3 55

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.

5

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.

7

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 3 55

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 19

EXTRACTION STEAMLP HEATERS1A, 2A, 3A

TO C

ON

DEN

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

Feedwa

ter

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

13

Extraction Steam Stop Valves and Non-return valves are used to protect the main turbine from:

OverspeedWater entering turbine

14

Water entering the main turbine is undesirable due to:

Erosion of the turbine bladesVibration of turbineBreakage of blades

15

COUNTER-WEIGHT TEST SWITCH

CYLINDER AND PISTON

EXTRACTION STEAM STOP CHECK VALVE

16

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


NO NO


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

18

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

19

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

HighI

LOW POINT DRAINS

Drain ManifoldCondenser


LSH

DRAIN POT

ORIFICE


I

EXTRACTION STEAM LINEDRAIN VALVE LOCATION

21

LP TURBINE

Stop Valve

Stop Check Valve


LSH

TT

I

DRAIN POT

ORIFICE

TT



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

22

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

23

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.

24

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

MARCMARCCOND

“B”COND

“B”

DUMPDUMPDUMPDUMP

DUMP

DUMP DUMPDUMP DUMP DUMP

LC

LC

LCLC

LC

LC LC

HDP HDP

A B DUMPHEATER 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

MARCMARCCOND

“B”COND

“B”

DUMPDUMPDUMPDUMP

DUMP

DUMP DUMPDUMP DUMP DUMP

LC

LC

LCLC

LC

LC LC

HDP HDP

A B DUMPHEATER DRAIN

SYSTEM

Rev 1

DUMP

MAIN STEAMMAIN STEAMMAIN STEAMMAIN STEAMMAIN STEAMMAIN STEAMMAIN STEAMMAIN STEAM

25

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.

26

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.

27

Moisture Separator Reheater

• Rising level will cause a Main Turbine Trip on HIGH Level (2/3 Level Switches) on 1/4 Moisture Separator Reheaters.

28

6A

LTC

LTB

LTA

LV4288FO

LV4284FO

FeedwaterHeater

5A

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)

29

5A LTC

LTB

LTA

LV4282FO

LV4286FO

FeedwaterHeater

4A

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)

30

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

31

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”

32

33

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.

34

35

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.

36

√

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

37

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.

38

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

ACADs (08-006) Covered Keywords Description Supporting Material

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