ACADs (08-006) Covered

KeywordsChemical and volume control system, normal letdown, charging, makeup water flow paths.

Description

Supporting Material

1.2.1.1 3.1.1.1 3.1.1.2 3.1.1.3 3.1.1.4 3.1.1.5 3.1.1.6 3.1.1.7

3.1.1.8 3.1.1.9 3.1.1.10 3.1.1.11 3.1.1.12 3.1.1.13 3.1.1.14 3.1.1.15

3.1.1.16 3.1.1.17 3.1.1.18 3.1.1.19 4.2.7.3 5.2.2.3 5.2.2.7

Chemical and Volume Control System (CVCS)

2

OBJECTIVES

5

1. List the functions of the Chemical & Volume Control System (CVCS).

2. State the function of each major component in the CVCS.

3. Describe the normal letdown, charging, and makeup water flow paths.

CVCS System

• Letdown System - removes water from the RCS for filtering, chemical adjustment, and radiation monitoring

• Charging System - returns water to the Reactor Coolant System (RCS) via the charging pumps from the Volume Control tank (VCT)

6

Functions of CVCS • Regulate RCS chemistry for reactivity and

corrosion control• Maintain pressurizer water level• Maintain seal water injection to Reactor

Coolant Pump (RCP) seals• Provides a means to fill, drain, and pressure

test the RCS• Provide injection to the RCS during

Emergency Core Cooling System (ECCS) initiation

7

CVCS components are made of austenitic stainless steel

8

TV130

ACCWLTDN

HX

BTRS381B

LTDNRHHX

128

RHR

8152 8160 15214

PRT

459 460

CLLP3

REGENHX

8149A 8149B 8149C

M

8146

M

8147

CLLP1

CLLP4

RCP 18141

M

BTRS

BORONSAMPLE

BTRS

600 # FC FC

FC

FC

FCFC

FC FC

FC

FO

129VCT

TIS129

TI130

PT131

300 #

131FO

HELBA

CIA-ACIA-B

IRCORC

8145PZR

81032

3

4FI

145

OTHERRCPS

FROMHEADVENT

PRT

CIA-A CIA-B

M M

8100

F

8112

8143

RCDT

123

809881538154

FROMRCSLP4

ACCW

HUT

EXCESSLTDN HX

112A

RCSFILTER

111B

BORON SAMPLE

8133

8115

8130

CATIONBED DEMIN

B A S T

RMWST

111ABLENDER

110A

188

505

8104

M

V C T

LI185

LI112

110BSI-A

SI-B

M

M

112B

112C

8471A

M

RWSTSI-A M

112D

112E

SI-BM

SI-A

CCP-A

8471B

M

SI-B

CCP-B

M

M

8509B

8508BSI-B

M M

RWST

RWST8509A

M

M8508ASI-A

SI-BM8111ASI-B

8111B

M SI-A

8110

8485A

S

190A 8116SI-A

M8438

S

M

8485B

190B

F F

PT121

SI-A

SI-B

M

M

8106

8105

SEALWATER

HXACCW

M

8109

M

RCP

BIT

121

NCP

BATP-A

BATP-B

150 #

104

106

CHARGING FLOW

LETDOWN FLOW

SEAL INJECTION FLOW

REACTOR MAKEUP

FC FCFC

FC

FC

IRCORC

IRC ORC

IRC ORC

M

182

SI-A&

SI-B

RE-48000

9

Chemical & Volume Control System

10

REGENERATIV EHx

LETDOWN Hx

8152 8160 15214

128

TV130

TV12

9

TV129

8115

BTRS381B

459 460

FC

FC

FCFCFC

FC FC FC

FC

FC

M

M

8146

8147

8145

8149C8149B8149A

M ix ed BedD eminer aliz er

M ix ed BedD eminer aliz er

Cation Bed

Demin

A CCW

BT RS F RO MCH A RGI N G

Cold L egL oop 3

Cold L egL oop 1

Cold L egL oop 4

PZ R

PRT

RH R

T o/ F r omBT RS

VCT

T OCH A RG I N G S U CT I O N

T o L W PS

RCSF i lt er

Letdown

Major Components

• Regenerative Heat Exchanger– transfers heat from letdown flow to

charging flow– reduces temperature of letdown prior

to orifices to prevent flashing of liquid to steam

– preheats charging to minimize thermal stress at RCS penetration

11

Regenerative Heat Exchanger

12

557°F

260°F

520520°°FF

100100°°FF

Letdown

ChargingTemperatures are

approximate

REGENERATIVE HEAT EXCHANGER

13

Regenerative Heat Exchanger

14

Major Components

• Letdown Orifices– reduce pressure and limit flow of RCS– two 75 gpm, one 45 gpm– combinations can be used to change

letdown flow

15

PRESSURE

PERMANENT PRESSURE

LOSS

Letdown Orifices

16

2235 psig

350 psig0 psig

Letdown Orifices (Isolation Valves)

17

Letdown Orifices

18

Letdown Orifices (Leak)

19

Major Components

• Letdown Heat Exchanger– Reduces RCS temperature prior to

entering mixed bed demineralizer– Cooled by Aux Component Cooling

Water (ACCW)– Reduces temperature to 115 F

20

Letdown Heat Exchanger

21

Major Components

• Demineralizers– maintain RCS purity– remove corrosion products– remove fission products– maximum flow rate of 120 gpm– operating temperature of ≈ 115 F

22

CONNECTION FOR LOADINGION EXCHANGE RESINS

UPPERRETENTION

SCREEN

CONNECTION FOR DISCHARGINGION EXCHANGE RESIN

BED OFION EXCHANGE

RESIN BEADS

ION EXCHANGEVESSEL

INFLUENT WATER(WATER TO BEPURIFIED)

EFFLUENT WATER(PURIFIED WATER)

LOWER RETENTIONSCREEN ELEMENT

Demineralizer

23

Major Components

• Volume Control Tank (VCT) – used to add hydrogen to RCS to

scavenge oxygen• minimizes corrosion of RCS

– used to degas reactor coolant– Net Positive Suction Head (NPSH) for

charging pumps– accepts makeup water to adjust RCS

boron concentration24

V C T

Letdown flow

Charging pump suction

Hydrogen

H2

N2

PC

PI

PC

PI

Waste Gas

Volume Control Tank (VCT)

25

Chemical & Volume Control System

26

Excess Letdow n

Seal W ater

Hx

Hx

FV121

FC

FC

FC

CCP B

NCP

CCP A

104

8149A

8149A

8149A

VCT

F r omL et down

1 0 6

T o/ F r omA CCW

T o/ F r omA CCW

F

F F

RCP

T o O t herRCPs

F r om O t herRCPs

F r omRCS L p4

F r omH ead Vent

REG ENERATIVEHx

FC

M

M

8146

8147

8145

Cold L e gL oop 1

Cold L e gL oop 4

PZ R

Charging

Major Components

• Centrifugal Charging Pumps (CCP)– Two, 11-stage CCPs– Auto start on SI signal– 150 gpm at 2800 psig– Powered from emergency 4160 VAC – Can be used for normal charging, but

not typically

27

Centrifugal Charging Pump

28

Major Components

• Normal Charging Pump (NCP)– One, 12-stage centrifugal pump– Normal source of charging flow– 130 gpm at 2543 psig– Not safety related - not required by

the Final Safety Analysis Report (FSAR)

29

NORMAL CHARGING PUMP

30

NORMAL CHARGING PUMP

31

Major Components

• Excess Letdown Heat Exchanger– Can supplement normal CVCS– Allows normal CVCS to be taken out of

service, but demineralizers are bypassed (temporary only)

– Can be routed to VCT, charging pump suction, or (Reactor Coolant Drain Tank) RCDT

– Cooled by ACCW

32

Excess Letdown Heat Exchanger

33

VCT

111A

BATP-B

BATP-A

111B

110A

F r omL et down

1 0 8

5 0 5

8 1 0 4

1 1 2 D

1 1 2 E

1 1 0 B

NCP

CCP B

CCP A

M

M

M

BLEN D ERBAST

F r omRW S T

F r omRM W S T

Chemical & Volume Control System

34

Makeup

Letdown / Charging Flow Path• Regenerative heat exchanger• Flow orifices• Letdown heat exchanger• Demineralizers• Volume control tank• Charging pumps• Regenerative heat exchanger

35

TV130

ACCWLTDN

HX

LV 459

LV460

CVCSLetdown CL Loop 3REGEN

HX

8149A 8149B 8149C

RCP 1

FC FC

FCFCFC

FOTI130

PT131

PV 131

FI132

IRCORC

FI145

Seal Injection to Other RCPS

HUTLV112A

V C T

SI-A

SI-B

M

M

112B

112C

FT121

SEALWATER

HXACCW

SIMPLIFIED CVCS SYSTEM

FV121

NCP CHARGING FLOW

LETDOWN FLOW

SEAL INJECTION FLOW

IRCORC

IRC

ORC

IRC ORC

HV182

FO

Total ChargingFlow – 87 gpm

SealInjectionFlow – 8 gpm

Charging Flow – 55 gpm(Total Charging Flow – TotalSeal Injection Flow)

TI127

Regen Hx Outlet Temp - 380°F

Letdown Pressure 360 - 380 psig

Letdown Flow – 75 gpm

Letdown Temperature - 115°F

Total Seal Injection Flow – 32 gpm

Charging FlowInto the RCS

Orifice IsolationValves

Seal Return From Other RCPS

Total Seal Return Flow – 12 gpm

TV130

ACCWLTDN

HX

LV 459

LV460

CVCSLetdown CL Loop 3REGEN

HX

8149A 8149B 8149C

RCP 1

FC FC

FCFCFC

FOTI130

PT131

PV 131

FI132

IRCORC

FI145

Seal Injection to Other RCPS

HUTLV112A

V C T

SI-A

SI-B

M

M

112B

112C

FT121

SEALWATER

HXACCW

SIMPLIFIED CVCS SYSTEM

FV121

NCP CHARGING FLOW

LETDOWN FLOW

SEAL INJECTION FLOW

IRCORC

IRC

ORC

IRC ORC

HV182

FO

Total ChargingFlow – 87 gpm

SealInjectionFlow – 8 gpm

Charging Flow – 55 gpm(Total Charging Flow – TotalSeal Injection Flow)

TI127

Regen Hx Outlet Temp - 380°F

Letdown Pressure 360 - 380 psig

Letdown Flow – 75 gpm

Letdown Temperature - 115°F

Total Seal Injection Flow – 32 gpm

Charging FlowInto the RCS

Orifice IsolationValves

Seal Return From Other RCPS

Total Seal Return Flow – 12 gpm

36

TV130

ACCWLTDN

HX

BTRS381B

LTDNRHHX

128

RHR

8152 8160 15214

PRT

459 460

CLLP3

REGENHX

8149A 8149B 8149C

M

8146

M

8147

CLLP1

CLLP4

RCP 18141

M

BTRS

BORONSAMPLE

BTRS

600 # FC FC

FC

FC

FCFC

FC FC

FC

FO

129VCT

TIS129

TI130

PT131

300 #

131FO

HELBA

CIA-ACIA-B

IRCORC

8145PZR

81032

3

4FI

145

OTHERRCPS

FROMHEADVENT

PRT

CIA-A CIA-B

M M

8100

F

8112

8143

RCDT

123

809881538154

FROMRCSLP4

ACCW

HUT

EXCESSLTDN HX

112A

RCSFILTER

111B

BORON SAMPLE

8133

8115

8130

CATIONBED DEMIN

B A S T

RMWST

111ABLENDER

110A

188

505

8104

M

V C T

LI185

LI112

110BSI-A

SI-B

M

M

112B

112C

8471A

M

RWSTSI-A M

112D

112E

SI-BM

SI-A

CCP-A

8471B

M

SI-B

CCP-B

M

M

8509B

8508BSI-B

M M

RWST

RWST8509A

M

M8508ASI-A

SI-BM8111ASI-B

8111B

M SI-A

8110

8485A

S

190A 8116SI-A

M8438

S

M

8485B

190B

F F

PT121

SI-A

SI-B

M

M

8106

8105

SEALWATER

HXACCW

M

8109

M

RCP

BIT

121

NCP

BATP-A

BATP-B

150 #

104

106

CHARGING FLOW

LETDOWN FLOW

SEAL INJECTION FLOW

REACTOR MAKEUP

FC FCFC

FC

FC

IRCORC

IRC ORC

IRC ORC

M

182

SI-A&

SI-B

RE-48000

37

Objectives Review

38

1. List the functions of the Chemical & Volume Control System (CVCS).

2. State the function of each major component in the CVCS.

3. Describe the normal letdown, charging, and makeup water flow paths.