safety evaluation of vhtr cogeneration system - iaea · pdf file ·...

Safety Evaluation of VHTR Cogeneration System

Hiroyuki Sato, Tetsuo Nishihara, Xinglong Yan, Kazuhiko Kunitomi

Japan Atomic Energy Agency

IAEA International Conference on Non-electric Applications of Nuclear Power

18 April 2007 Oarai Japan

JAEA R&D for the VHTR system

High temperature operation (950℃) : 2004

Continuous hydrogen production 30NL/h 175hr : 2005

HTTR

IS Process

HTTR-IS system

World’s first demonstration of hydrogen production utilizing heat from nuclearpower

Hydrogen production rate : 800～1000 Nm3/h

Commercial VHTR systemCommercial VHTR system

Hydrogen production for commercial use

Economically competitive(20.5 JPY / Nm3 *)

2010 2030

* T. Nishihara et al., Proc. of 15th International Conference on Nuclear Engineering, ICONE15-10157 (2007).

GTHTR300C (170MWth for H2 plant)for Cogeneration of electricity and hydrogen

• Electricity generation : 202MWe• Hydrogen production rate : 2.6MNm3/h

GTHTR300C (370MWth for H2 plant)for Hydrogen production only

• Hydrogen production rate : 5.6MNm3/h• Electricity generation for H2 plant

GTHTR300CGTHTR300C (170MWth for H2 plant)for Cogeneration of electricity and hydrogen

• Electricity generation : 202MWe• Hydrogen production rate : 2.6MNm3/h

GTHTR300CGTHTR300C (370MWth for H2 plant)for Hydrogen production only

• Hydrogen production rate : 5.6MNm3/h• Electricity generation for H2 plant

Japanese Design of VHTR Cogeneration system

ReactorIHX

Precooler

Turbine

Generator

IS Process

Recuperator

Compressor

X. Yan et al., Proc. of 3rd information exchange meeting on nuclear production of hydrogen (2005).

950℃

900℃

Plant Layout of GTHTR300C

Heat Exchangers VesselReactor Pressure Vessel

Gas Turbine & IHX Vessel

2nd Loop He Circulator

Reactor Power Plant

IS Hydrogen Plant

HI Decomposition Facility Bunsen Reaction Facility

H2SO4 Decomposition Facility

Confinement Isolation Valves

GTHTR300C

Basic Philosophy of GHTHR300C Design

ReactorIHX

Precooler

Generator

IS Process

Recuperator

Non-nucleargrade

Nuclear grade

CompressorTurbine

Why Non-nuclear grade IS process ?Open the door to non-nuclear industries- IS process will be managed by oil and gas companies

Reducing the construction costs of the IS process- Apply the chemical plant design standard to the IS process

Why Non-nuclear grade IS process ?Open the door to non-nuclear industries- IS process will be managed by oil and gas companies

Reducing the construction costs of the IS process- Apply the chemical plant design standard to the IS process

Non-nuclear Design for IS process

a. Establishment of IS process thermal load disturbance absorption method

b. Countermeasure for H2 explosion

c. Countermeasure for toxic gas inflow to reactor control room

d. Reduction of tritium releasing to environment & mixing to product H2

a. Establishment of IS process thermal load disturbance absorption method

b. Countermeasure for H2 explosion

c. Countermeasure for toxic gas inflow to reactor control room

d. Reduction of tritium releasing to environment & mixing to product H2

Nuclear grade

Non-nuclear grade

b.

a.

c.

IS process Reactor facility

d.

R&D for non-nuclear grade IS processR&D for non-nuclear grade IS process

Safety philosophy for non-nuclear grade IS process*Safety philosophy for non-nuclear grade IS process*

Exempt the IS process from Prevention system 3 (PS-3)

Identify the abnormal events initiated in IS process as external events

*K. Ohashi, et. Al., J. Atom. Energ. Soc. Jpn., Vol.6, No.1 (2007)

Chemical reactor

Reactor

Primary System

2nd He gas system

IHX

Processapparatus

Loss of IS process Thermal Load

Turbo machine

Process apparatus failure e.g. Pump trip, Leakage

Loss of chemical reaction

Turbine inlet temperature increase

Outlet temperature increase

Turbine trip

Reactor scram

Countermeasure for loss of the IS process thermal load is required Countermeasure for loss of the IS process thermal load is required

Operational Sequence for GTHTR300CDecrease of H2 plant load

Turbine inlet temperatureincrease

Actuation of CV3

Turbine inlet temperature drop

Turbine inlet flow rate variation

Turbine inlet temperature control

Core flow rate decrease

Power generation variation

Actuation of CV1

Power generation rate control

Reactor power control

TurbineCompressor

Precooler

Reactor

IHX

Recuperator

From H2Plant

To H2Plant

～

CV2CV1

CV3

V4

CV1 : Turbine bypass flow control valve

CV2 : Recuperator inlet temperature control valve

CV3 : Turbine inlet temperature control valve

V4 : Turbine bypass valve

Dynamic Simulation Code for GTHTR300C

Component modelGas TurbineCompressorControl system

Reactor kineticsPoint nuclear kinetic equationReactor kinetics data

Thermal-hydraulic modelNon-condensable gas modelField equationsMass continuity, Momentum conservation,Energy conservation

Heat transfer correlation equationExperimental equation, Conventional equation

Compressor

TurbineIHX

Reactor core

Pre-cooler

Recuperator

CV3

CV1

CV2

VCSFlow Diagram of the Analytical Model of GTHTR300C

TurbineCompressor

Precooler

Reactor

IHX

Recuperator

From H2Plant

To H2Plant

～

CV2CV1

CV3

V4





600

800

1000

1200

1400

IHX

seco

ndar

y in

let

heliu

m g

as

tem

pera

ture

[K]

1000

1050

1100

1150

1200

020406080100

Turb

ine

inle

t he

lium

gas

te

mpe

ratu

re [K

]

CV3 flow

rate [kg/s]

356035703580359036003610

0246810

0 200 400 600 800 1000Turb

ine

rota

tiona

l sp

eed

[rpm

] CV1 flow

rate [kg/s]

Elapsed time from loss of H2 plant load [s]

- Loss of thermal load of H2 Plant (170MW) in GTHTR300C -Dynamic Calculation (1/2)

Elapsed time from loss of the IS process thermal load [s]

19 K

5 rpm

0100200300400500

Hea

t tra

nsfe

r qu

antit

y [M

W]

280300320340360380

350400450500550600650

Rea

ctor

inle

t flo

w ra

te [k

g/s] R

eactor pow

er [MW

]

TurbineCompressor

Precooler

Reactor

IHX

Recuperator

From H2Plant

To H2Plant

～

CV2CV1

CV3

V4





- Loss of Thermal Load of H2 Plant (170MW) in GTHTR300C -Dynamic Calculation (2/2)

0

500

1000

1500

0 200 400 600 800 1000

Rea

ctor

out

let

tem

pera

ture

[K]


Pre cooler

Elapsed time from loss of the IS process thermal load [s]

150MWIHX

50MW

100MW

Concluding Remarks

・ JAEA started the R&D for the safety design ofcommercial VHTR systems GTHTR300C

・ Dynamic simulation models of GTHTR300Cwas developed

・ Loss of the H2 plant thermal load can be absorbedby the operational sequence

Thanks for your [email protected]

Back ground information

IHX heat transfer correlation(Shell side)

(800<Re<7000)

(Re>7000)

(Tube side)

Analytical model of IHX

40801

.. PrReCNu =3060 ..

2 PrReCNu =

⎟⎟⎠

⎞⎜⎜⎝

⎛⋅

+×−

= )/(..)/(

)diRe(.

.PrPrdiRe.Nu 615260

65 06150100570

02230

C1,C2 : Design Coefficient

0

500

1000

1500

0

50

100

150

200

Turb

ine

inle

t he

lium

gas

te

mpe

ratu

re [K

]

CV3 flow

rate [kg/s]

TurbineCompressor

Precooler

Reactor

IHX

Recuperator

From H2Plant

To H2Plant

～

CV2CV1

CV3

V4






600

800

1000

1200

1400

IHX

seco

ndar

y in

let

heliu

m g

as

tem

pera

ture

[K]

3800390040004100420043004400

020406080100

0 200 400 600 800 1000

Rot

atio

nal

spee

d [r

pm] C

V1 flow rate [kg/s]


0100200300400500

-400

-200

0

200

400

Pre

cool

er

heat

tran

fer

quan

tity

[MW

]

IHX heat transfer quantity [M

W]

0

500

1000

1500

0 200 400 600 800 1000

Rea

ctor

out

let

tem

pera

ture

[K]


250300350400450500

0100200300400500600700

Rea

ctor

flow

in

let [

kg/s

] Reactor

power [M

W]

TurbineCompressor

Precooler

Reactor

IHX

Recuperator

From H2Plant

To H2Plant

～

CV2CV1

CV3

V4






IHX

Pre cooler

4

4.5

5

5.5

012345

IHX

heliu

m g

as

pres

sure

[MPa

] Pressure ratio

250300350400450500

0100200300400500600700

Rea

ctor

flow

in

let [

kg/s

] Reactor

power [M

W]

- Loss of thermal load of H2 Plant (370MW) in GTHTR300C -Dynamic calculation (4/4)

Primary

Secondary

CompressorTurbine

0

500

1000

1500

0 200 400 600 800 1000

Rea

ctor

out

let

tem

pera

ture

[K]


IHX pressure difference

MAX: +0.16 MPa

Reactor inlet flow rate variation

: -59.7 kg/s

Reactor power variation

: -293 MW

Reactor outlet temperature

: Constant


MAX: +0.16 MPa


: -59.7 kg/s


: -293 MW


: Constant

1000

1050

1100

1150

1200

020406080100

Turb

ine

inle

t he

lium

gas

te

mpe

ratu

re [K

]

CV3 flow

rate [kg/s]

- Loss of thermal load of H2 Plant (170MW) in GTHTR300C -

356035703580359036003610

0246810

0 200 400 600 800 1000Turb

ine

rota

tiona

l sp

eed

[rpm

] CV1 flow

rate [kg/s]


Thermal disturbanceIHX

2nd inlet

: +400 K

TurbineInlet

: +19.7 K

Turbine R.P.M. increase

: + 5 r.p.m.


2nd inlet

: +400 K

TurbineInlet

: +19.7 K


: + 5 r.p.m.

Dynamic calculation (1/4)

600

800

1000

1200

1400

IHX

seco

ndar

y in

let

heliu

m g

as

tem

pera

ture

[K]


280300320340360380

350400450500550600650

Rea

ctor

inle

t flo

w ra

te [k

g/s] R

eactor pow

er [MW

]

4.44.64.8

55.25.4

0246810

IHX

heliu

m g

as

pres

sure

[MPa

] Pressure ratio


CompressorTurbine

PrimarySecondary

0

500

1000

1500

0 200 400 600 800 1000

Rea

ctor

out

let

tem

pera

ture

[K]



MAX: +0.19 MPa


: -34.0 kg/s


: -93.5 MW


: Constant


MAX: +0.19 MPa


: -34.0 kg/s


: -93.5 MW


: Constant


100010501100115012001250

0

50

100

150

200

Turb

ine

inle

t he

lium

gas

te

mpe

ratu

re [K

]

CV3 flow

rate [kg/s]

600

800

1000

1200

1400IH

X se

cond

ary

inle

the

lium

gas

te

mpe

ratu

re [K

]


3800390040004100420043004400

020406080100

0 200 400 600 800 1000

Rot

atio

nal

spee

d [r

pm] C

V1 flow rate [kg/s]



2nd inlet

: +400 K

TurbineInlet

: +201 K


: + 90 r.p.m.


2nd inlet

: +400 K

TurbineInlet

: +201 K


: + 90 r.p.m.

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