1

DOE Generation IV Energy Conversion

Supercritical CO2 Cycle Development

Paul Pickard (SNL)Technical Director – Gen IV Energy Conversion

MIT S-CO2 SymposiaMarch 6, 2007

2

Generation IV Energy Conversion

• Electrical generation - Gen IV Energy Conversion Program

• Hydrogen production - Nuclear Hydrogen Initiative (NHI)

300 400 500 600 700 800 900 1000 1100Temp C

VHTRGFR

SFRSCWR

High Temp Elect

He Brayton

MSRTemperature Ranges

300 400 500 600 700 800 900 1000 1100Temp C

VHTRGFR

LFRSFR

SCWR

Sulfur Cycles

He BraytonS-CO2 Brayton

MSR

Alt Cycles Hydrogen Production Temperature RangesHydrogen Production

Methods

Electrical Conversion TechnologiesRankine

Gen IV Reactor Output

3

Gen IV Energy Conversion Objectives: Optimize performance and cost effectiveness of Gen IV reactors

Generator

CompressorStages

Turbine Stages

Heat Sink

Blower

Interstage Cooling

Interstage Heating

Gen IV RX

Motor

Generator

CompressorStages

Turbine Stages

Heat Sink

Blower

Interstage Cooling

Interstage Heating

Gen IV RX

Motor200

400

600

800

1000

1200

19 20 21 22 23 24 25 26 27 28entropy (j/g*K)

Tem

pera

ture

(K)

Interstage Heated, Cooled - He Cycle

Cycle Efficiencies vs Source Temperature for fixed component efficiencies and system effectiveness

0%

10%

20%

30%

40%

50%

60%

200 300 400 500 600 700 800 900 1000

Source Temperature (°C)

Cyc

le E

ffici

ency

(%)

1t/1c rec He BraytonSCSF CO2 Brayton3t/6c IH&C He Brayton

Figure 13: T-s diagram for split flow recuperated Brayton cycle using CO2 bew een 7.5 and 22.5 MPa w ith 29% of the flow diverted by the interm ediate com pressor

(eff=49%)

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1000

1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9 3.1

entropy (J/g*K)

tem

pera

ture

(K)

phase dome

low er comp

LT HP rec

HT HP rec

Qin

turbine

HT LP rec

LT LP rec

Qrej

interm comp

Reactor

Generator

Motor

Main Compressor

Turbine Stages

Heat Sink

Motor

Motor

RecompressorLow Temp

Recuperator

High Temp Recuperator

Split Flow S-CO2 Brayton Cycle

Brayton Cycle Options for Gen IV Reactors

Figure 11: T-s plot for simple Brayton cycle using Helium flow at 6.9 and 23 MPa w ith SC steam bottoming cycle w ith mass flow ratio of 1.241 w ater/helium

(eff=48%)

300.00

400.00

500.00

600.00

700.00

800.00

900.00

1000.00

15.0 16.0 17.0 18.0 19.0 20.0 21.0 22.0 23.0 24.0

entropy (kJ/kg(helium)*K)

Tem

pera

ture

(K)

Q transfered

comp

Q in Brayton

turbine

steam dome

steam dome

Rankine pump

Q transfered

Q in Rankine

Steam Turbine

Q rejection

T-s diagram for single stage Recuperated Helium Brayton cycle between 5 and 10 MPa

200

400

600

800

1000

1200

19 20 21 22 23 24 25 26 27 28entropy (j/g*K)

Tem

pera

ture

(K)

Rankine Bottoming Cycle Recuperated He Cycle

4

FY07 Gen IV Power Conversion

S-CO2 - intermediate temperature reactors (500-700 C)• High efficiencies in intermediate temperature ranges• Relatively compact, little additional complexity • Potential for reduced capital costs• Key issues – compression near critical point, control strategy

for split flow

1

2

6

Compressor

T=305 K

P= 20 MPa

Alternator/Motor 1000 rpm

Waste Heat Cooler

T=331 K

2.82 kg/s

= 90kW

502 kW

90 kW

P= 7.5 MPa

P= 7.5 MPa

= 90kW

Flow Orifice Inst.

FY07 Task Areas1. S-CO2 system design (MIT)2. S-CO2 control analysis (ANL, MIT) 3. PCHE heat transfer experiments (ANL)4. S-CO2 materials testing (MIT, LANL)5. Initiate construction of small scale S-

CO2 compression exps and (~ MW) class split flow Brayton cycle system (SNL, Industry)

0-60 VAC5000 A

440 VAC, 770 A

TT

PRESSURIZER

P

EXHAUST

CO2

LEVELDETECTOR

COLDLEG

HOTLEG

POWER SUPPLY

F TTW WTT WTT WTT FT

FT FT FT

FT

PP

TF

WT

= ABSOLUTE PRESSURE

= DIFFERENTIAL PRESSURE

= FLUID TEMPERATURE

= WALL TEMPERATURE

P

CO2GEARPUMP

HEATRIC HX

CORIOLISFLOWMETER

FILTER

FT

DIELECTRICUNION

= RELIEF VALVE

P

P FILTER

COLDLEGHOT

LEG FTFT

5

Supercritical CO2 Cycle ActivitiesPower Conversion System Studies (MIT)

• FY06 studies developed layouts for PCS ratings ranging from 20 to 1200MWe

• “3rd generation” concepts evolved from earlier MIT studies, addressed impact of ductwork pressure drop on thermodynamic efficiency;

• Radial compressors used for main compressor (1 stage ~0.85) and recompressor (3 stages ~0.89)

• Modular approach to extend power range

• Reference version - 300MWe two-train recuperator configuration using parallel clusters of commercial HEATRICTM PCHE

• FY07 activities at MIT focus on control simulations

2nd Generation SCO2 300Mwe PCS

2nd Generation S- CO2 300Mwe PCS

3rd Generation

Net efficiency = 0.47 @650 C versus 0.45 for 2nd generation PCS

Pre cooler

LTR

HTR

T

RC

6

S-CO2 Controls – Model Development, Simulation (ANL, MIT)

• S-CO2 control strategy Options

• Earlier tasks refined analysis tools at MIT and ANL

• GASS-PASS/CO2 (MIT, ANL) – fast running, adaptable code now operational – including radial compressor models

• ANL Plant Dynamics Code –incorporated radial compressor models – simulated control options for LFR/S-CO2

• FY07 studies use updated models to simulate range of control strategies for S-CO2 cycle

3

4

1

5

21 – In-reactor heat exchanger bypass valve

2 – Turbine inlet/throttle valve

3 – Turbine bypass valve

4 – Inventory control tanks and valves

5 – Flow split valve

7

Closed Brayton Cycle Testing

SNL CBC Testing For Gen IV Pure Gases Gas Mixtures

Test Date1/11/2006 10/17/2006 3/16/2006 5/25/2006 1/11/2006 3/16/2005 3/16/2005 3/23/2006

Gas Type Description N2 Ar CO2 He 90N2-10Ar 90Ar-10He 80Ar-20He 70N2-30HeCp J/kg*K 1026 518 844 5378 941.4 571 634 1221k(300K) mW/m*K 26 18 16 154 26 24 33.1 46k(1000K) mW/m*K 60 42 54 336 59 56 72 105Ro (J/kg*K) 297 208 188.9 2079 284 229 254 399MW (gm/mole) 28 39.9 44.01 4 29 36.4 32.7 21Gamma 1.407 1.66 1.316 1.66 1.433 1.66 1.66 1.486

SS Inventory Test x x Mix xSS Temperature Increase x x x Mix xSS Flow and RPM Op-Curves x x Mix x x xSS Operating Pwr Curve x x Mix x x xSS Operating Pressure Ratio x x Mix x x xTransient RPM Step Decrease (5000 rpm) x Mix x x xTransient RPM Step Increase (1000 rpm) x x x Mix x x xTransient Startup x x x Mix xTransient Shutdown x x Mix x xSS MW Increase xSS MW Decrease x x

CBC operational data for model comparisons

•Transient, steady state operations

•Working fluids -- N2, He, Ar, CO2, mixtures

• Operational data for --Inventory, temperature changes, startup, shutdown, power changes

8

Comparison of Measurements and Predictions

SNL 30 kWe CBC Measurements Dynamic Model Predictions

Startup InventoryReductions

TIT Increase 650 K,700 K,750K

RPM Increase Shutdown

10 kPa Argon Addition

dP =10 kPa5 Steps

RPM/5000

Power (kW)

100% N2

Heater Power (%)

Gas Coolant Temps (K)

Startup InventoryReductions

TIT Increase 650 K,700 K,750K

RPM Increase Shutdown

10 kPa Argon Addition

dP =10 kPa5 Steps

RPM/5000

Power (kW)

100% N2

Heater Power (%)

Gas Coolant Temps (K)

Startup InventoryReductions

TIT Increase 650 K,700 K,750K

RPM Increase Shutdown

10 kPa Argon Fill

dP =10 kPa

100% N2

Heater Power (%)

Gas Coolant Temps (K)

10 kPa Bleed

Startup InventoryReductions

TIT Increase 650 K,700 K,750K

RPM Increase Shutdown

10 kPa Argon Fill

dP =10 kPa

100% N2

Heater Power (%)

Gas Coolant Temps (K)

10 kPa Bleed

Startup InventoryReductions

TIT Increase 650 K,700 K,750K

RPM Increase Shutdown

10 kPa Argon Addition

dP =10 kPa5 Steps

RPM/5000

Power (kW)

100% N2

Heater Power (%)

Gas Coolant Temps (K)

Startup InventoryReductions

TIT Increase 650 K,700 K,750K

RPM Increase Shutdown

10 kPa Argon Addition

dP =10 kPa5 Steps

RPM/5000

Power (kW)

100% N2

Heater Power (%)

Gas Coolant Temps (K)

Startup InventoryReductions

TIT Increase 650 K,700 K,750K

RPM Increase Shutdown

10 kPa Argon Fill

dP =10 kPa

100% N2

Heater Power (%)

Gas Coolant Temps (K)

10 kPa Bleed

Startup InventoryReductions

TIT Increase 650 K,700 K,750K

RPM Increase Shutdown

10 kPa Argon Fill

dP =10 kPa

100% N2

Heater Power (%)

Gas Coolant Temps (K)

10 kPa Bleed

Temperatures

Pressure

Power

Rpm and flow

9

S-CO2 PCHE Heat Transfer Testing Facility -- ANL

0-60 VAC5000 A

440 VAC, 770 A

TT

PRESSURIZER

P

EXHAUST

CO2

LEVELDETECTOR

COLDLEG

HOTLEG

POWER SUPPLY

F TTW WTT WTT WTT FT

FT FT FT

FT

PP

TF

WT

= ABSOLUTE PRESSURE

= DIFFERENTIAL PRESSURE

= FLUID TEMPERATURE

= WALL TEMPERATURE

P

CO2GEARPUMP

HEATRIC HX

CORIOLISFLOWMETER

FILTER

FT

DIELECTRICUNION

= RELIEF VALVE

P

P FILTER

COLDLEGHOT

LEG FTFT

• Initial configuration - CO2-to-water heat exchange tests• 17.5 KW heat duty PCHE represents section of cooler for S-CO2

Brayton cycle• FY07 upgrade to CO2 to CO2 configuration (started in FY06).

(low temperature recuperator).

• Conducted initial series of CO2-to-water steady state under prototypical conditions.

• Determined average heat transfer coefficients on the water and CO2 sides. Compared ANL PCHE modeling with test data

• Good agreement is obtained for the heat exchange rate, Q, or CO2 and H2O outlet temperatures. CO2 side pressure drop is overpredicted

10

Small Scale S-CO2 Cycle Demonstration Loop

• Next stage of S-CO2 development –construct small scale S-CO2 power conversion system to demonstrate key technology issues

• Phased approach – key technical issues first -- and budget constraints

• First stage – experiments to address compression near critical point

• Progress to split flow recuperated Brayton cycle demo

• Contracts (FY06) solicited TM Industry input on small scale test loop to test key technical features (BNI, P&W-Rocketdyne)

1

23

5

6

6

T=825 K

Heater

Compressors

Turbineh = 0.94

Compressorh = 0.84

T=304.5 KP=7.5 MPa

Alternator

Waste Heat Cooler

Tfuel

~1070 K

Turbine

Recuperator

Low Pressure

High Pressure T=355 KT=498 K

20 MPa

T=683 K

4 7

T=707 K

T=505 K T=375K4.7 kg/s

1.88 kg/s819 kW

502 kW

~ 1086 kW ~707kW

317 kW197 kW605 kW 90 kW

2.82 kg/s

1

23

5

6

6

T=825 K

Heater

Compressors

Turbineh = 0.94

Compressorh = 0.84

T=304.5 KP=7.5 MPa

Alternator

Waste Heat Cooler

Tfuel

~1070 K

Turbine

Recuperator

Low Pressure

High Pressure T=355 KT=498 K

20 MPa

T=683 K

4 7

T=707 K

T=505 K T=375K4.7 kg/s

1.88 kg/s819 kW

502 kW

~ 1086 kW ~707kW

317 kW197 kW605 kW 90 kW

2.82 kg/s

Primary FY06 SOW Tasks • Review key technical issues for full

scale system • Examine approach for S-CO2

compression tests • Phased approach to develop full cycle,

preliminary cost and schedule

11

Key Technology for S-CO2 DevelopmentSNL LDRD -- S-CO2 other working fluids

S-CO2 Main Compressor TestElectric Motor Driven Option

Motor Comp

Liftoff Gas Seal

Ball BearingsGimbal MountTo Measure Torque

TurbineExpander

Major Technology IssuesGas Liftoff SealsEfficiency of CompressionThermal Input ControlBearings and Thrust LoadsOff-Normal behavior (wet)

Turbo Assisted Motor/ CompressorReduces motor power requirementsAllow modification – wheels, housings could be replaced with different designs.

1

23m

6

Compressor

CO2

h

η= 0.72

T=335 KP=19.99 MPa

Motor Alternatorη = 0.95

Waste HeatGas Chiller

Turbine

Recuperator

T=305 KP=7.69 MPa

T=306.2KP=7.84 MPa

3 kg/s

47 kW 75.5 kW28.4 kW28.4 kW

η= 0.85

Heater

1

23m

6

Compressor

CO2

h

η= 0.72

T=335 KP=19.99 MPa

Motor Alternatorη = 0.95

Waste HeatGas Chiller

Turbine

Recuperator

T=305 KP=7.69 MPa

T=306.2KP=7.84 MPa

3 kg/s

47 kW 75.5 kW28.4 kW28.4 kW

η= 0.85

Heater

Phase 1-LS: Turbo Assisted Main Compressor Study SC-CO2 Flow Compression (3 kg/s)

12

Gen IV S-CO2(1 MWth => 300 kWe with Split Flow)

Compressors Alternator

Waste Heat Cooler

TurbineAssist

Low PwrRecuperator

Low Pressure

High Pressure

T=355 KT=498 K

20 MPa

5 kg/s

2 kg/s

3kg/s

7 MPa

Compressors Alternator

Waste Heat Cooler

TurbineAssist

Low PwrRecuperator

Low Pressure

High Pressure

T=355 KT=498 K

20 MPa

5 kg/s

2 kg/s

3kg/s

7 MPa

Compressors Alternator

Waste Heat Cooler

TurbineAssist

Low PwrRecuperator

Low Pressure

High Pressure

T=355 KT=498 K

20 MPa

5 kg/s

2 kg/s

3kg/s

7 MPa

Heater

1 MWcapability

Compressors Alternator

Waste Heat Cooler

TurbineAssist

Low PwrRecuperator

Low Pressure

High Pressure

T=355 KT=498 K

20 MPa

5 kg/s

2 kg/s

3kg/s

7 MPa

Heater

1 MWcapability

1

23

5

6

6

T=825 K

Heater

Compressors

Turbineh = 0.94

Compressorh = 0.84

T=304.5 KP=7.5 MPa

Alternator

Waste Heat Cooler

Tfuel

~1070 K

Turbine

Recuperator

Low Pressure

High Pressure T=355 KT=498 K

20 MPa

T=683 K

4 7

T=707 K

T=505 K T=375K4.7 kg/s

1.88 kg/s819 kW

502 kW

~ 1086 kW ~707kW

317 kW197 kW605 kW 90 kW

2.82 kg/s

1

23

5

6

6

T=825 K

Heater

Compressors

Turbineh = 0.94

Compressorh = 0.84

T=304.5 KP=7.5 MPa

Alternator

Waste Heat Cooler

Tfuel

~1070 K

Turbine

Recuperator

Low Pressure

High Pressure T=355 KT=498 K

20 MPa

T=683 K

4 7

T=707 K

T=505 K T=375K4.7 kg/s

1.88 kg/s819 kW

502 kW

~ 1086 kW ~707kW

317 kW197 kW605 kW 90 kW

2.82 kg/s

Phase 1 - Split flow (Main and Recompressor) Study

Phase 2 - Non-recuperated Braytonsplit flow

Phase 3 – Recuperated split flow S-CO2 cycle

No Heater ~ 40 kWe MotorConsumes Electricity

Up to 1 MW Heater ~ 40 kWe Alternator PwrProduces Electricity

~1 MW Heater & ~40 kWe Motor/Alternator+ 300 kW Dynometer or 300 kWe Alt. is an OptionProduces Electricity

Phase 2

Phase 3

Phase 1

13

Gen IV Energy ConversionFY07 S-CO2 Summary

Develop experimental capability to address key technical issues– Main compressor operation, – System control strategies – Heat transfer experiments

Approach: phased design, construction – Address main compressor exps first– Split flow compression as first stage of small scale system – Optimize construction sequence to provide early results and

leverage previous phase

Planning Schedule for Gen IV scope– Gen IV funding - ~ 4 year schedule– Other SC fluids work on supercritical compression studies– GNEP – other program involvement

14

Gen IV Energy Conversion S-CO2 cycle phases, proposed schedule

SustainableSystem Selection

Dev Phase

S-CO2 Cycle Development

Components

Small Scale

Pilot Scale

Adv Cycle Eval. Key Technology Exps Pilot Scale Demo2005 2007 2009 2011 2013 20142012201020082006

S-CO2 Design / Eval

Main Comp, PCHE Exps

Split flow comp exps Non- recup

Brayton

Recup Brayton

Pilot Scale S-CO2 system design and technology demonstration

MW S-CO2 split flow devel.

15

Extra VGs

16

SNL LDRD Single Shaft SC-CO2 opt for SC-XeLab-Scale 120 kWth Heater Power : 7 kWe SC-CO2 : 33 kWe SC-Xe

1

23m

6

Compressor

CO2

h

η= 0.72

T=335 KP=19.99 MPa

Motor Alternatorη = 0.95

Waste HeatGas Chiller

Turbine

Recuperator

T=305 KP=7.69 MPa

T=306.2KP=7.84 MPa

3 kg/s

47 kW 75.5 kW28.4 kW28.4 kW

η= 0.85

Heater

1

23m

6

Compressor

CO2

h

η= 0.72

T=335 KP=19.99 MPa

Motor Alternatorη = 0.95

Waste HeatGas Chiller

Turbine

Recuperator

T=305 KP=7.69 MPa

T=306.2KP=7.84 MPa

3 kg/s

47 kW 75.5 kW28.4 kW28.4 kW

η= 0.85

Heater

Heater

1

2

4

4

Compressor

CO2

η= 0.85 η= 0.72

T=335.2 KP=19994 kPa

Motor Alternator Waste HeatGas Chiller

Turbine

Recuperator

T=305 KP=7690 kPa

T=307.1KP=7843 kPa

3.0 kg/s

56.4 kW 75.5 kW-19.1 kW123 kW

3T=350 KP=19594 kPa

T=335.2 KP=19994 kPa

T=307.4 KP=7834 MPa

120 kWHeater

1

2

4

4

Compressor

CO2

η= 0.85 η= 0.72

T=335.2 KP=19994 kPa

Motor Alternator Waste HeatGas Chiller

Turbine

Recuperator

T=305 KP=7690 kPa

T=307.1KP=7843 kPa

3.0 kg/s

56.4 kW 75.5 kW-19.1 kW123 kW

3T=350 KP=19594 kPa

T=335.2 KP=19994 kPa

T=307.4 KP=7834 MPa

120 kW

1

2

4

4

HeaterCompressor

CO2

η= 0.85 η = 0.72

T=308.8 KP=8797 kPa

Motor Alternator Waste HeatGas Chiller

Turbine

Recuperator

T=305 KP=7690 kPa

T=773.5 KP=7886 kPa

.9 kg/s

9.5kW 7.31 kW 2.2 kW112.4 kW

3T=783 KP=8579 kPa

T=670 KP=8687 kPa

T=318.7 KP=7787 MPa

120 kW

500 kW

1

2

4

4

HeaterCompressor

CO2

η= 0.85 η = 0.72

T=308.8 KP=8797 kPa

Motor Alternator Waste HeatGas Chiller

Turbine

Recuperator

T=305 KP=7690 kPa

T=773.5 KP=7886 kPa

.9 kg/s

9.5kW 7.31 kW 2.2 kW112.4 kW

3T=783 KP=8579 kPa

T=670 KP=8687 kPa

T=318.7 KP=7787 MPa

120 kW

500 kW

120 kW LDRDSC-CO2 / SC-Xe

120 kW LDRDSC-CO2 / SC-Xe

1 LS

2 LS

3 LS

SC-CO2 Comp. LDRD

Phase 1-LS: Turbo Assisted Main Compressor Study SC-CO2 Flow Compression (3 kg/s)

Phase 2-LS: Un-Recup. Brayton CycleSC-CO2 & SC-Xe Compression Higher TIT various RPMsSC-CO2 and SC-Xe

Phase 3-LS: Split Flow S-CO2 & XeBrayton Cycle with Recup.

No Heater ~ 30 kWe MotorConsumes Electricity

120 kW Lab-Scale Heater ~ 20 kWe Motor Pwr CO2~ 10 kWe Alternator Pwr XeConsumse &Produces

Electricity

~120 kW Heater & ~40 kWe Motor/Alternator+ 300 kW Dynometer300 kWe Alt. is an OptionProduces Limited Electricity 7- 32 kWe (CO2/Xe)

17

Small Scale S-CO2 Demo UnitConceptual Approach

Phase 1 - Main compressor and/or Recompressorwith/without split flow

Phase 2 – Non-recuperated BraytonSplit flow

Compressors Alternator

Waste Heat Cooler

TurbineAssist

Low PwrRecuperator

Low Pressure

High Pressure

T=355 KT=498 K

20 MPa

5 kg/s

2 kg/s

3kg/s

7 MPa

Compressors Alternator

Waste Heat Cooler

TurbineAssist

Low PwrRecuperator

Low Pressure

High Pressure

T=355 KT=498 K

20 MPa

5 kg/s

2 kg/s

3kg/s

7 MPa

Compressors Alternator

Waste Heat Cooler

TurbineAssist

Low PwrRecuperator

Low Pressure

High Pressure

T=355 KT=498 K

20 MPa

5 kg/s

2 kg/s

3kg/s

7 MPa

Heater

1 MWcapability

Compressors Alternator

Waste Heat Cooler

TurbineAssist

Low PwrRecuperator

Low Pressure

High Pressure

T=355 KT=498 K

20 MPa

5 kg/s

2 kg/s

3kg/s

7 MPa

Heater

1 MWcapability

1

23

5

6

6

T=825 K

Heater

Compressors

Turbineh = 0.94

Compressorh = 0.84

T=304.5 KP=7.5 MPa

Alternator

Waste Heat Cooler

Tfuel

~1070 K

Turbine

Recuperator

Low Pressure

High Pressure T=355 KT=498 K

20 MPa

T=683 K

4 7

T=707 K

T=505 K T=375K4.7 kg/s

1.88 kg/s819 kW

502 kW

~ 1086 kW ~707kW

317 kW197 kW605 kW 90 kW

2.82 kg/s

1

23

5

6

6

T=825 K

Heater

Compressors

Turbineh = 0.94

Compressorh = 0.84

T=304.5 KP=7.5 MPa

Alternator

Waste Heat Cooler

Tfuel

~1070 K

Turbine

Recuperator

Low Pressure

High Pressure T=355 KT=498 K

20 MPa

T=683 K

4 7

T=707 K

T=505 K T=375K4.7 kg/s

1.88 kg/s819 kW

502 kW

~ 1086 kW ~707kW

317 kW197 kW605 kW 90 kW

2.82 kg/s

No Heater & ~40 kWe Motor

Up to 1 MW Heater & ~40 kWe Motor/AlternatorProduces Electricity

~1 MW Heater & ~40 kWe Motor/Alternator+ 300 kW Dynamometer Produces Limited Electricity

Phase 3 – Split Flow S-CO2 Brayton

18

• Expected interaction mode in PCHE –small cracks – form oxides or carbonates – could lead to plugging if not removed, E release not primary concern.

• Does not appear to be major issue for current Na outlet temperatures – but need to confirm

• Significantly less of a concern than water – Na reaction

• ABR program – constructing a small facility to investigate plugging issue (ANL)

• ABR will investigate Na CO2 interactions,

• Gen IV focus on cycle development

Gen IV Energy ConversionS-CO2 Interactions

• CO2 reaction with Na at higher temperatures • Japanese observed slow reactions below ~ 550 C, increasing

reaction rates above 550 C• Korean data (CO2 bubbled into Na Column) suggest some

reaction below ~ 550 C

Sodium-CO2 reaction (Japanese results)

19

CO2 / H2O Heat Exchanger

0-60 VAC5000 A

440 VAC, 770 A

TT

RELIEF

EXHAUST

PRESSURIZER

TO 25 kW CHILLER

DRAWING: CO2 LOOPSCHEMATIC # 3DRAWING NO.: CO2L79DRAWN BY: D. KILSDONKDATE: 10/7/04FILE: CO2L_LS3.DWG(AC70)

P

RELIEFEXHAUST

He

CO2

2 m

1 m

LEVELDETECTOR COLD

LEGHOTLEG

POWER SUPPLY

P

F TTW WTT WTT WTT FT

FT FT FT

FTTF

PP

TF

WT

= ABSOLUTE PRESSURE

= DIFFERENTIAL PRESSURE

= FLUID TEMPERATURE

= WALL TEMPERATURE

P

He CO2

PUMP

HEATRIC HX

FLOWMETER

0-60 VAC5000 A

440 VAC, 770 A

TT

RELIEF

EXHAUST

PRESSURIZER

DRAWING: CO2 LOOPSCHEMATIC # 4DRAWING NO.: CO2L80DRAWN BY: D. KILSDONKDATE: 10/7/04FILE: CO2L_LS4.DWG(AC70)

P RELIEF

EXHAUSTHe

CO2

1 m

LEVELDETECTOR

COLDLEG

HOTLEG

POWER SUPPLY

P

F TTW WTT WTT WTT FT

FT FT FT

FTTF

PP

TF

WT

= ABSOLUTE PRESSURE

= DIFFERENTIAL PRESSURE

= FLUID TEMPERATURE

= WALL TEMPERATURE

P

PUMP

HEATRIC HX

CO2 He

TT

RELIEF

EXHAUST

P

P

F FT

FTTF

25 kW CHILLER

COLDLEG

HOTLEG

PUMP

FLOWMETER

FLOWMETER

CO2 / CO2 Heat Exchanger Design

ANL S-CO2 Heat Transfer Loop

20

Gen IV Energy Conversion Objectives: Optimize performance and cost effectiveness of Gen IV reactors

Generator

CompressorStages

Turbine Stages

Heat Sink

Blower

Interstage Cooling

Interstage Heating

Gen IV RX

Motor

Generator

CompressorStages

Turbine Stages

Heat Sink

Blower

Interstage Cooling

Interstage Heating

Gen IV RX

Motor200

400

600

800

1000

1200

19 20 21 22 23 24 25 26 27 28entropy (j/g*K)

Tem

pera

ture

(K)

Rankine Bottoming CycleMulti Reheat - Interstage cooled Brayton Cycle

Cycle Efficiencies vs Source Temperature for fixed component efficiencies and system effectiveness

0%

10%

20%

30%

40%

50%

60%

200 300 400 500 600 700 800 900 1000

Source Temperature (°C)

Cyc

le E

ffici

ency

(%)

1t/1c rec He BraytonSCSF CO2 Brayton3t/6c IH&C He Brayton

Figure 13: T-s diagram for split flow recuperated Brayton cycle using CO2 bew een 7.5 and 22.5 MPa w ith 29% of the flow diverted by the intermediate com pressor

(eff=49%)

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1000

1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9 3.1

entropy (J/g*K)

tem

pera

ture

(K)

phase dome

low er comp

LT HP rec

HT HP rec

Qin

turbine

HT LP rec

LT LP rec

Qrej

interm comp

Reactor

Generator

Motor

Main Compressor

Turbine Stages

Heat Sink

Motor

MotorRecompre

ssorLow Temp Recuperator

High Temp Recuperator

Split Flow S-CO2 Brayton Cycle

Brayton Cycle Options for Gen IV Reactors

Reactor

Generator

Motor

Compressor

Turbine

Generator

Motor

To Heat Sink

From heat sink

SteamTurbine

Pumping Stages

Circ

Steam DryerBypass

Circ

Figure 11: T-s plot for simple Brayton cycle using Helium flow at 6.9 and 23 MPa w ith SC steam bottoming cycle w ith mass flow ratio of 1.241 w ater/helium

(eff=48%)

300.00

400.00

500.00

600.00

700.00

800.00

900.00

1000.00

15.0 16.0 17.0 18.0 19.0 20.0 21.0 22.0 23.0 24.0

entropy (kJ/kg(helium)*K)

Tem

pera

ture

(K)

Q transfered

comp

Q in Brayton

turbine

steam dome

steam dome

Rankine pump

Q transfered

Q in Rankine

Steam Turbine

Q rejection