Development of a 3D Neutron Kinetic-Thermal-hydraulic …...Development of a 3D Neutron Kinetic-Thermal-hydraulic Model for an RBMK Reactor by RELAP5-3D© CodeCode C. Parisi, M. Cherubini,

Development of a Development of a 3D Neutron Kinetic3D Neutron Kinetic--ThermalThermal--hydraulic hydraulic

Model for an RBMK Reactor by Model for an RBMK Reactor by RELAP5RELAP5--3D3D©© CodeCode

C. ParisiC. Parisi, M. , M. CherubiniCherubini, F. D, F. D’’AuriaAuria(San Piero A Grado Nuclear Research Group )

DIMNP – University of Pisa - ITALY

2006 RELAP5-3D© Users Seminar Holiday Inn SunSpree Resort – West Yellowstone – USA

16 – 18 August 2006

ContentsContents

•• Main Goal and StepsMain Goal and Steps•• ThermalThermal--hydraulic modelinghydraulic modeling

QualificationQualificationTransient resultsTransient results

•• Neutron Parameters DatabaseNeutron Parameters Database•• RBMK peculiarities and 3D NK modelingRBMK peculiarities and 3D NK modeling

QualificationQualificationTransients Results Transients Results

•• ConclusionsConclusions

1) Core

2) Water pipe

3) Reactor bottom plate

4) Group Distribution Header

5) Shield

6) Steam Drum

7) Steam Water Pipe

8) Reactor top plate

9) Refuelling machine

10) Reactor lid structure

11) Top reactor channel

12) Downcomers

13) Pressure Header

14) Suction header

15) Main Coolant Pump

Framework of the activitiesFramework of the activities

12 units still in operation12 units still in operation

1 unit under construction (Kursk 5)1 unit under construction (Kursk 5)

Development of Plants life extension (50 yrs)Development of Plants life extension (50 yrs)

NEEDS TO INCREASE & IMPROVE

KNOWLEDGE FORTHIS TECHNOLOGY

TACIS Project TACIS Project R2.03/97 part BR2.03/97 part B

RBMK Sketch

A project funded

by the

European Union

Develop a reliable tool Develop a reliable tool for detailed 3D NK for detailed 3D NK –– TH TH

analyses of RBMK systemanalyses of RBMK system

Main Goal & Steps 1/2Main Goal & Steps 1/2

RELAP5RELAP5--3D3D©©

TH NODALIZATION

RELAP5RELAP5--3D3D©© (NESTLE)(NESTLE)3D NK-TH

COUPLED MODEL

VALIDATION & VALIDATION & CALCULATIONSCALCULATIONS

HELIOSHELIOSXSec

LIBRARIESGENERATION VALIDATION & VALIDATION &

CALCULATIONSCALCULATIONS

VALIDATIONby MonteMonte--Carlo Carlo

calculationscalculations

Main Goal & Steps 2/2Main Goal & Steps 2/2

•• RELAP5RELAP5--3D3D©© hadhad a a centralcentral rolerole in the in the assembledassembledChainChain of of CodesCodes forfor RBMK severe RBMK severe accidentsaccidents analysesanalyses

TH modeling 1/5TH modeling 1/5Relap5-3D©

nodalisation

sketch of the right side

TH modeling 2/5TH modeling 2/5Steam Drum FW Steam Line ICV, MSV, BRU-K, BRU-D

TH modeling 3/5TH modeling 3/5Downcomers Suction Header Suction pipes Pumps Pressure Header

Group Distribution Header Water lines

TH modeling TH modeling 4/54/5Core & Graphite stack Steam water lines

22 hydraulic volumes for the active part

Graphite Gap

TH modeling 5/5TH modeling 5/5

Adopted code resourcesNumber of NodesNumber of Nodes 42724272

Number of JunctionsNumber of Junctions 44114411

Number of Heat structuresNumber of Heat structures 45614561

Number of Mesh PointsNumber of Mesh Points 3259032590

Number of active structures (fuel + graphite)Number of active structures (fuel + graphite) 6464

Main modelled subsystemsMain modelled subsystems Right sideRight side Left sideLeft side

Number of GDHNumber of GDH 2222

2424

22

11

Number of PumpsNumber of Pumps 44 44

Number of Bypass linesNumber of Bypass lines 44 44

11

Number of Core channelsNumber of Core channels 77

Number of Steam DrumsNumber of Steam Drums 22

Number of Additional Absorber channelsNumber of Additional Absorber channels 11

Basic condition for TH system codes useBasic condition for TH system codes use::

Frozen code versionFrozen code version

User qualificationUser qualification

Nod. qualification process Nod. qualification process

Steady stateSteady state

On transientOn transient

Qualification ProcessQualification Process


Steady State level – Volume vs. Height

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0

Height (m)

Volu

me

(m3)

NodalizationSmolensk 3 NPP

BAF TAF SD in

Qualification ProcessQualification ProcessSteady State level- DP vs. Length

6.25E+06

6.50E+06

6.75E+06

7.00E+06

7.25E+06

7.50E+06

7.75E+06

8.00E+06

8.25E+06

8.50E+06

8.75E+06

9.00E+06

Pres

sure

(Pa)

DC inlet

Pump Head

PH GHD out Core outCore in SWL in SD in

Qualification Process Qualification Process -- SS levelSS level

RELAP5

right side No QUANTITY Unit Design

left side

AcceptableError (o) Error Notes

1 Circuit volume m3 667.67

667.78 1% 0.01%

For right side

3

Active structures heat transfer area

(overall)

m2

5919.4 (fuel & PT)

6712.0 (Graphite-Gap)

5919.6 5906.5 0.1% 0.03%

-12%

Error on Graphite-

Gap surface due to

different geometry

5

Active structures heat transfer volume

(overall)

m3 14.423 378.7

14.427 408.44 0.2% 0.02%

7.8%

Error on Graphite-

Gap surface due to

different geometry

6 Volume vs. height curve m3 -- -- 10% 5% Max

error

Nodalisation geometrical check

Qualification Process Qualification Process -- SS levelSS levelRELAP5

right side N. Quantity Unit Design

left side

Acceptable

Error (o) Error Notes

1629 1628.1 0.05% 1 Thermal power MW 1583 1588.1 2% -0.3%

6.861 6.862 -0.01% -0.03%2 DS pressure MPa 6.86

6.859 6.859 0.1%

0.01% 0.01% On all

SD dome

269 0.37% 3 Core inlet temperature

oC 270 269 0.5% 0.37%

284.5 0.1% 4 DS inlet temperature

oC 284 284.5 0.5% 0.1%

15.5 5 Average quality in the core exit

% 14.5 15.3 ?

6 DS feed water temperature

oC 165 165 0.5% 0.0% Imposed Value

7 Maximum fuel rod temperature surface

oC ? 298 10

104.7 0.4% 8 MCP speed rad/s 104.2 104.7 1% 0.4% Imposed

Value 0.496 ÷ 0.51 0.8% ÷ - 2% 9 Pressure drop on

the water line 0.5 0.491 ÷ 0.497 1.8% ÷ 0.6% 0.64÷0.658 2.5%÷ -0.15% 10 Pressure drop on

the core 0.657 0.654÷0.658 0.46%÷ -0.15% 0.376÷0.387 4%÷1.3%

11 Pressure drop on the steam-water line

MPa

0.392 0.366÷0.369

10%

6.6%÷5.9%

For 2.049 MW

channel

12 Total pressure drop on the TC MPa 1.549 10%

13 MCP head MPa 1.51 1.512 10% -0.13% For all pumps

14 PS total mass inventory tons ? 801 2%

89.5 91.4 -5% -7% 15 DS mass inventory m3 85±?

86.8 87.8 2%

-2% -3%

Liquid Fraction Volume

5157.9 5185.2 -0.5% 16 Total loop coolant flow rate Kg/s 5103.9 5106 2% -0.04%

105.82 103.5 2% 18 Additional absorber

flow rate Kg/s 105 92.5

10% 12%

0.6% 19

Balance between feed water and steam mass flow rate

% 0.0 0.7%

?

485 20 Average graphite

temperature oC ?

484 ?

Steady Statedemonstration:

20 selected parameters

-300.0 -250.0 -200.0 -150.0 -100.0 -50.0 0Time (s)

265.0

270.0

275.0

280.0

285.0

290.0

295.0

300.0

305.0

Tem

pera

ture

(°C

)

XXX LOP17b tempf145260000X

X

XX

X XX X X X X X X X X X X X X

YYY LOP17b tempf214260000

Y

Y Y YY

YY Y Y Y Y Y Y Y Y Y Y Y Y

ZZZ LOP17b tempf145470000Z

ZZ Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z

VVV LOP17b tempf214470000V

V V V V V V V V V V V V V V V V V

-300.0 -250.0 -200.0 -150.0 -100.0 -50.0 0Time (s)

5000

5050

5100

5150

5200

5250

5300

5350

Mas

s Fl

ow ra

te (K

g/s)

XXX V8=V5+V6+V7

X

X

X

X

X

XX X X X X X X X X X X X


SD pressure

Core flow rateright side

Core inlet-outlet tempright side

AA flow rateright side

-350.0 -300.0 -250.0 -200.0 -150.0 -100.0 -50.0 0Time (s)

6.75

6.80

6.85

6.90

6.95

7.00

7.05

Pres

sure

(MPa

)

XXX LOP17b p360010000X

X

XX

XX X X X X X X X X X X X

YYY LOP17b p410010000

Y

YY


ZZZ LOP17b p860010000

Z

Z

ZZ

ZZ Z Z Z Z Z Z Z Z Z Z Z Z

VVV LOP17b p910010000

V

VV

VV V V V V V V V V V V V V

-300.0 -250.0 -200.0 -150.0 -100.0 -50.0 0Time (s)

96.0

98.0

100.0

102.0

104.0

106.0

108.0

110.0

112.0

Mas

s Fl

ow R

ate

(Kg/

s)

XXX LOP17b mflowj142200000

X

X X XX X X X X X X X X X X X X X

-300.0 -250.0 -200.0 -150.0 -100.0 -50.0 0Time (s)

80.0

85.0

90.0

95.0

100.0

105.0

110.0

Volu

me

(m^3

)

XXX LOP17b cntrlvar401

X

XX

XX

X X X X X X X X X X X X X

YYY LOP17b cntrlvar403

Y

YY

YY

Y Y Y Y Y Y Y Y Y Y Y Y Y

ZZZ LOP17b cntrlvar405

Z

Z ZZ

ZZ Z Z Z Z Z Z Z Z Z Z Z Z Z

VVV LOP17b cntrlvar407

VV

V VV

V V V V V V V V V V V V V

-300.0 -250.0 -200.0 -150.0 -100.0 -50.0 0Time (s)

250

300

350

400

450

500

550

600

650

Tem

pera

ture

(°C

) XXX LOP17b httemp145401301

X X X X X X X X X X X X X X X X X X X

YYY LOP17b httemp145401302

Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y

ZZZ LOP17b httemp145401303

Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z

VVV LOP17b httemp145401304

V V V V V V V V V V V V V V V V V VJJJ LOP17b httemp145401305

J J J J J J J J J J J J J J J J J J

HHH LOP17b httemp145401306

H H H H H H H H H H H H H H H H H

### LOP17b httemp145401307

# # # # # # # # # # # # # # # # #

OOO LOP17b httemp145401308

O O O O O O O O O O O O O O O O O

AAA LOP17b httemp145401309

A A A A A A A A A A A A A A A A

BBB LOP17b httemp145401310

B B B B B B B B B B B B B B B B

CCC LOP17b httemp145401311

C C C C C C C C C C C C C C C

DDD LOP17b httemp145401312

D D D D D D D D D D D D D D D


Graphite radial tempdistribution

13th plane

SD volume

Clad Temp. axial distribution

-300.0 -250.0 -200.0 -150.0 -100.0 -50.0 0Time (s)

270.0

275.0

280.0

285.0

290.0

295.0

300.0

305.0

310.0

315.0

Tem

pera

ture

(°C

)

XXX LOP17b httemp214500212

X

XX

XX X

X X X X X X X X X X X X X

YYY LOP17b httemp214500312

Y

Y Y YY


ZZZ LOP17b httemp214500412

Z

Z Z Z ZZ Z Z Z Z Z Z Z Z Z Z Z Z Z

VVV LOP17b httemp214500512

V V VV V

V V V V V V V V V V V V V

JJJ LOP17b httemp214500612

J J J JJ J J J J J J J J J J J J J

HHH LOP17b httemp214500712H H H H H H H H H H H H H H H H H### LOP17b httemp214500812# # # # # # # # # # # # # # # # #OOO LOP17b httemp214500912

O O O O O O O O O O O O O O O O O

AAA LOP17b httemp214501012

A A A A A A A A A A A A A A A A

BBB LOP17b httemp214501112

B B B B B B B B B B B B B B B B

CCC LOP17b httemp214501312

C C C C C C C C C C C C C C C

DDD LOP17b httemp214501412

D D D D D D D D D D D D D D D

EEE LOP17b httemp214501512

E E E E E E E E E E E E E E

FFF LOP17b httemp214501612

F F F F F F F F F F F F F F

GGG LOP17b httemp214501712

G G G G G G G G G G G G G

III LOP17b httemp214501812

I I I I I I I I I I I I I

LLL LOP17b httemp214501912

L L L L L L L L L L L L

MMM LOP17b httemp214502012

M M M M M M M M M M M M


On Transient levelREPLICATION OF A SELECTED TEST

Accuracy quantificationQualitative evaluation

LOSS of POWERComparisonwith exp. data

FFT BM

Comparison with Russian results

Qualification Process Qualification Process –– On TransientOn TransientTime sequence of main events

UnipiUnipiTime (s)Time (s)

EventEvent RussianRussianTime (s)Time (s)

0.0. Loss of preferred AC power supply. Diesel generators start.Loss of preferred AC power supply. Diesel generators start. 0.0.

0.40.4

1.01.0

1.01.0

1.01.0

226.226.

15.015.0

55.055.0

180.0180.0

600.600.

1211.1211.

3000.3000.

0.40.4 Turbine isolation and regulation valves fully closed.Turbine isolation and regulation valves fully closed.

1.01.0 11stst AZAZ--5 command issued by CPS upon EPPS reading that turbine valve has5 command issued by CPS upon EPPS reading that turbine valve has closed. closed. This signal isThis signal is neglected in the simulation.neglected in the simulation.

1.01.0 22ndnd AZAZ--5 command issued as a result of pressure downstream turbine valv5 command issued as a result of pressure downstream turbine valve falling e falling to 12 bar. This signal isto 12 bar. This signal is credited in the simulation. Pcredited in the simulation. Power begins to reduce. CPS rods ower begins to reduce. CPS rods start moving.start moving.

1.01.0 BRUBRU--K valves start to open due to overK valves start to open due to over--pressure. BRUpressure. BRU--K operate as pressure K operate as pressure controller with opening and closure setcontroller with opening and closure set--points equal to 7.11 MPa and 6.86 MPa points equal to 7.11 MPa and 6.86 MPa respectively respectively

3.03.0 First group of MSV start to open.First group of MSV start to open.

15.015.0 Diesel generators reach nominal loading.Diesel generators reach nominal loading.

55.055.0 2 EFWP starts.2 EFWP starts.

180.180. BRUBRU--K valves are fully closed.K valves are fully closed.

600.600. BRUBRU--D valves are closed.D valves are closed.

1090.1090. The operator switch off EFWP on level signal. The operator switch off EFWP on level signal.

3000.3000. Final problem timeFinal problem time

Qualification Process Qualification Process –– On TransientOn Transient

SD pressure

Right & left power

Right & left total flow rate Steam line mass flow rate

-500. 0 500. 1000. 1500. 2000. 2500. 3000.Time (s)

6.60

6.80

7.00

7.20

7.40

7.60

7.80

8.00

Pres

sure

(MPa

)

XXX LOP17b p360010000X

XXXXXX

X

X

X X

X X

XX

X

X

X

X

X

YYY LOP17b p410010000

Y

YYYYYY

Y

Y

Y

YY

Y

YY

Y YY

Y Y

ZZZ LOP17b p860010000

Z

ZZZZZ

Z

Z

ZZ

Z

Z Z

Z

ZZ

Z

Z

Z

Z

VVV LOP17b p910010000

V

VVVVV

V

V

V

V

V

V V

V

V

V

V

V

VV

-500. 0 500. 1000. 1500. 2000. 2500. 3000.Time (s)

0

.25

.5

.75

1

1.25

1.5

1.75

2

2.25x 10 9

Pow

er (W

)

WinGraf 4.1 - 01-20-2005

XXX LOP17b cntrlvar127

XXXXXXX

X

XX X X X X X X X X X X

YYY LOP17b cntrlvar463Y

YYYYYY

Y

YY Y Y Y Y Y Y Y Y Y Y

-500. 0 500. 1000. 1500. 2000. 2500. 3000.Time (s)

0

1000

2000

3000

4000

5000

6000

Mas

s Fl

ow R

ate

(Kg/

s)

XXX V8=V5+V6+V7XXXXXXX

X

XX

XX X X X X

X X X X

YYY V63=V61+V62+V60YYYYYYY

YYY

Y Y Y YY Y Y

Y Y Y

-500. 0 500. 1000. 1500. 2000. 2500. 3000Time (s)

-500

0

500

1000

1500

2000

2500

3000

3500

4000

Mas

s Fl

ow R

ate

(Kg/

s)

XXX LOP17b mflowj397000000X

XXXXXX

XXX X X X X X X X X X X

YYY LOP17b mflowj447000000

Y

YYYYYY

YYY Y Y Y Y Y Y Y Y Y Y


MSV mass flow rate

BRU-K mass flow rate

BRU-D mass flow rate

-500. 0 500. 1000. 1500. 2000. 2500. 3000Time (s)

-50

0

50

100

150

200

250

300

Mas

s Fl

ow R

ate

(Kg/

s)


XXXXXXX

X

XX X X X X X X X X

X

X


YYYYYYYYYY Y Y Y Y Y Y Y Y Y Y

ZZZ LOP17b mflowj958000000

ZZZZZZZZZZ Z Z Z Z Z Z Z Z Z Z

VVV LOP17b mflowj959000000

VVVVVVVVVV V V V V V V V V V V

-500. 0 500. 1000. 1500. 2000. 2500. 3000.Time (s)

-25

0

25

50

75

100

125

150

175

200

225

Mas

s Fl

ow R

ate

(Kg/

s)


XXXXXXX

X

X

X X X X X X X X X X X


YYYYYYY

Y

Y

Y Y Y Y Y Y Y Y Y Y Y

ZZZ LOP17b mflowj950000000

ZZZZZZZ

Z

Z

Z

Z Z Z Z Z Z Z Z Z Z

VVV LOP17b mflowj951000000

VVVVVV

V

V

VV

V V V V V V V V V V

-500. 0 500. 1000. 1500. 2000. 2500. 3000.Time (s)

-20

0

20

40

60

80

100

120

140

Mas

s flo

w ra

te (K

g/s)


XXXXXXX

X

X

X X X X X X X X X X X

Qualification Process Qualification Process –– On TransientOn TransientSteam Drum pressure vs. time

6.6

6.8

7

7.2

7.4

7.6

7.8

8

-500 0 500 1000 1500 2000 2500 3000

Time (s)

Pres

sure

(MPa

)

SD 1 ru SD 1 unipi

Qualification Process Qualification Process –– On TransientOn TransientMSV group 1 Mass flow rate vs. time

0

50

100

150

200

250

300

-500 -200 100 400 700 1000 1300 1600 1900 2200 2500 2800

Time (s)

Mas

s flo

w ra

te (K

g/s)

MSV 1 group ru MSV 1 group unipi


0

1000

2000

3000

4000

5000

6000

-500 0 500 1000 1500 2000 2500 3000

Time (s)

Mas

s Fl

ow ra

te (K

g/s)

Total flow rate RU Total flow rate Unipi

Core Mass flow rate vs. time

Considerations on TH modelConsiderations on TH model

• The pioneering study (for UNIPI) of the RBMK reactor type gave the following results:

•Steady State level: all the limits regarding the geometrical fidelity have been fulfilled; precision of few parameters should be improved (i.e. SD mass inventory)•On transient level: a qualitative comparison between Russian and UNIPI results shows some discrepancies (e.g. MSV timing)

• The same phenomena are predicted from both calculations (SD pressure trend)

• Lacking of measured values does not permit the application of the FFT-BM to quantify the accuracy of the obtained results

• The nodalisation is capable to reproduce the selected transient –LOOP – even though some improvements are necessary

Successive stepSuccessive step development of 3D NK model

RBMK 3D NK PeculiaritiesRBMK 3D NK Peculiarities•• RBMK peculiaritiesRBMK peculiarities::

Loosely coupled coreLoosely coupled coreLargeLarge number of nodes (30000)number of nodes (30000)24882488 channels (channels (15701570 FC, FC, 314314 nonnon--FC FC (AA, Axial detectors,..), and (AA, Axial detectors,..), and 604604Reflector ChannelsReflector Channels))Complex neutron Complex neutron XSecsXSecs structure structure (graphite & fuel temp, water density, (graphite & fuel temp, water density, Xenon Xenon concconc,.. feedbacks),.. feedbacks)Different CR arrangements & type:Different CR arrangements & type:

Up & Bottom InsertedUp & Bottom InsertedManual CR, Shortened CR, Fast Manual CR, Shortened CR, Fast Acting Scram CRActing Scram CR

Manual CR Shortened CR Fast CR

Neutron Database Neutron Database -- CodeCodeHELIOSHELIOS::

1D1D-- 2D neutron2D neutron--gamma gamma transport code for transport code for lattice lattice burnupburnupcomplete geometric flexibilitycomplete geometric flexibilityGenerate FewGenerate Few--Groups Groups Macroscopic Macroscopic XSecsXSecs LibrariesLibraries

ENDF/B-VI NJOY MultiG XSec

HELIOS

→

j→

j

→

j

Graphite Zirconium Alloy (Э125)UO2

Zirconium Alloy (Э110)Coolant

Graphite Zirconium Alloy (Э125)UO2

Zirconium Alloy (Э110)Coolant

→

j→

Φ

* NEM-Cross Section Table Input * * T Fuel T Mod. Rho Cool. CXe 3 4 6 0 * ******* X-Section set # 1 * * Group No. 1 * *************** Diffusion Coefficient Table * .5570000E+03 .8500000E+03 .1030000E+04 .5570000E+03 .7000000E+03 .8560000E+03 .1060000E+04 .1000000E+02 .1000000E+03 .3000000E+03 .5000000E+03 .7440000E+03 .9980000E+03 .1161020E+01 .1161020E+01 .1161000E+01 .1161440E+01 .1161430E+01 .1161420E+01 .1160100E+01 .1160100E+01 .1160090E+01 .1157710E+01 .1157680E+01 .1157680E+01 .1159020E+01 .1159020E+01 .1159010E+01 .1159440E+01 .1159420E+01 .1159410E+01 .1158080E+01 .1158060E+01 .1158060E+01 .1155670E+01 .1155650E+01 .1155640E+01 .1153360E+01 .1153330E+01 .1153300E+01 .1153740E+01 .1153710E+01 .1153700E+01 .1152390E+01 .1152360E+01 .1152340E+01 .1149940E+01 .1149910E+01 .1149890E+01 .1146530E+01 .1146480E+01 .1146460E+01 .1146920E+01 .1146850E+01 .1146830E+01 .1145540E+01 .1145490E+01 .1145470E+01 .1143070E+01 .1143020E+01 .1142980E+01 .1137150E+01 .1137100E+01 .1137090E+01 .1137520E+01 .1137460E+01 .1137460E+01 .1136130E+01 .1136080E+01 .1136050E+01 .1133630E+01 .1133580E+01 .1133550E+01 .1126540E+01 .1126500E+01 .1126480E+01 .1126880E+01 .1126840E+01 .1126800E+01 .1125490E+01 .1125440E+01 .1125400E+01 .1122970E+01 .1122890E+01 .1122850E+01 * *************** Total Absorption X-Section Table

XSecs Libraries

1D – 2D Transport Calculations

•• Database function of:Database function of:ExposureExposureFuel temperatureFuel temperatureGraphite temperatureGraphite temperatureCoolant densityCoolant density

•• 675 675 Compositions Compositions for fuel cells: for fuel cells: 610610for nonfor non--fuel cells: fuel cells: 6565

• Operational data obtained with radial & axial in-core detectors • Reactor core divided axially into 10 layers with a height of 70.0 cm• Upper and lower axial reflectors have a thickness of 30 cm• All non-fuel cell type considered• Validation of the Neutron Cross Sections DatabaseNeutron Cross Sections Database by precise Monte CarloMonte Carlo calculationscalculations

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

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29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56

GraphiteZirconium Alloy (Э125)Aluminum AlloyCR Channel CoolantGraphite

UO2

CoolantZirconium AlloyAbsorber

Graphite Zirconium Alloy (Э125) UO2

Zirconium Alloy (Э110) Coolant

Graphite Zirconium Alloy (Э125) UO2

Zirconium Alloy (Э110) Coolant

SmolenskSmolensk--3 NPP status at 16.10.19963 NPP status at 16.10.1996

FC cell

MCR cell

Neutron Database Generation 2/2Neutron Database Generation 2/2

RBMK TH/3D NK Model DevelopedRBMK TH/3D NK Model Developed

Number of Volumes : 4728

Number of Meshes for Heat Transfer : 32400

Number of Axial Meshes per TH channel : 20

Number of TH channels : 58

Economy of Code resources

3D NK Core 3D NK Core ModelingModeling & Qualification& Qualification

• 29856 Neutron Kinetic Nodes

• All CR Types (Manual, Shortened, Safety), Axial Detectors & Additional Absorbers Simulated

• Bottom, Top and Radial Graphite Reflector Modelled

NESTLE 3D NK modelNESTLE 3D NK model

•• Radial power peaking factor Radial power peaking factor –– 1.621.62•• Radial power distribution: RMS from 130 radial detectors Radial power distribution: RMS from 130 radial detectors –– 7%7%•• Axial power distribution: RMS from 12 axial detectors Axial power distribution: RMS from 12 axial detectors –– 8%8%

0.00

0.20

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0.60

0.80

1.00

1.20

1.40

0 100 200 300 400 500 600 700

Distance from the Bottom (cm)

NESTLE_DETECTORSSMOLENSK_3_DETECTORS

2D Core Power2D Core PowerAxial Core Peaking FactorAxial Core Peaking Factor

3D NK 3D NK SensitivitySensitivity AnalysisAnalysis

•• SeveralSeveral teststests performedperformed forfor axialaxial power power distributiondistributionchangingchanging NESTLE NESTLE numericalnumerical methodsmethods

•• Pure CMFD Pure CMFD methodmethod resultedresulted more more robustrobust thanthan NEM NEM forfor thisthis core core configurationconfiguration

0

0.2

0.4

0.6

0.8

1

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1.6

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Distance from the BOTTOM (cm)

Axi

al P

OW

ER

NEM_CHB_5REFERENCE_DETECTORSCMFD_CHB_5CMFD_CHB_0CMFD_CHB_20FINAL

RBMK Transient AnalysesRBMK Transient Analyses

•• Several Plant transients were proposed and analyzed in order Several Plant transients were proposed and analyzed in order to check the codes capabilities in modeling RBMK phenomena:to check the codes capabilities in modeling RBMK phenomena:

CR Withdrawal CR Withdrawal **CR Bank Withdrawal CR Bank Withdrawal **GDH RuptureGDH RuptureFlow Blockage in GDH Flow Blockage in GDH **Flow Blockage in FC Flow Blockage in FC **CPS cooling LOCA CPS cooling LOCA

* * = sample results given in next slides= sample results given in next slides

Sample Results 1/3Sample Results 1/3

0.00E+00

5.00E+05

1.00E+06

1.50E+06

2.00E+06

2.50E+06

3.00E+06

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0

Time (s)

Pow

er (W

)

214_EQ669_EQ259_EQ265_EQ

RELAP5-3D© CR Bank Withdrawal

Local power

0 10.0 20.0 30.0 40.0 50.0 60.0 70.0Time (s)

3.1

3.15

3.2

3.25

3.3

3.35

3.4x 10 9

Pow

er (W

)

WinGraf 4.1 - 08-17-2005

XXX RBMK_CR_Withdrawal rkotpow0

X

X

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RELAP5-3D© CR Withdrawal

Total power

CR GROUP WITHDRAWAL

CR WITHDRAWAL

CR GROUP WITHDRAWAL

CR WITHDRAWAL

• CR system (CPS) operating at lowpressure CR / CRbank withdrawal at 0.4 m/s

•CR Bank withdrawalgenerated scram signal(Reactor Power 106% of Nominal Power)

0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0Time (s)

540.0

545.0

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565.0

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580.0

Tem

pera

ture

(K)

WinGraf 4.1 - 08-16-2005

XXX RBMK_CR_BANK_W httemp669500812

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YYY RBMK_CR_BANK_W httemp265501112Y

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ZZZ RBMK_CR_BANK_W httemp259500812Z

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VVV RBMK_CR_BANK_W httemp214501012V

V

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VV V V V V V V V V V V V V

RELAP5-3D© CR Bank Withdrawal

Clad Temperature for affected zone


0 50.0 100.0 150.0 200.0 250.0 300.0Time (s)

-2.00

-1.00

0

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Mas

s Fl

owra

te (K

g/s)

WinGraf 4.1 - 08-19-2005

XXX RBMK_GDH_BLOCKAGE mflowj214

XX

X XX

X

XX

X X X XX

X XX X X X

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YYY RBMK_GDH_BLOCKAGE mflowj259

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ZZZ RBMK_GDH_BLOCKAGE mflowj265

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ZZ Z

RELAP5-3D© GDH Blockage

Flow oscillations in blocked FC


Clad temperatures in hot-FC

Time trend of the main events:

0.0 sec. – onset of the GDH Blockage; coolant flowrateby the ECCS by-pass line5.0 secs. – onset of mass

flow oscillations in the affected FCs140 secs. – Pressure tube

reaches maximum temperature

0 50.0 100.0 150.0 200.0 250.0 300.0Time (s)

3.06

3.08

3.1

3.12

3.14

3.16

3.18x 10 9

Pow

er (W

)

WinGraf 4.1 - 08-17-2005

XXX RBMK_GDH_BLOCKAGE rkotpow0

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Total Reactor Power

0 50.0 100.0 150.0 200.0 250.0 300.0Time (s)

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(K)

WinGraf 4.1 - 08-17-2005

XXX RBMK_GDH_BLOCKAGE httemp214501512

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YYY RBMK_GDH_BLOCKAGE httemp259501812

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Y

Y YY

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Y YY

YY Y

YY

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ZZZ RBMK_GDH_BLOCKAGE httemp265501612

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VVV RBMK_GDH_BLOCKAGE httemp669501412

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VV V V

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JJJ RBMK_GDH_BLOCKAGE httemp175501612

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J J J J J J J J JJ

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HHH RBMK_GDH_BLOCKAGE httemp244501012

H H H H H H H H H H H H H H H H

0 50.0 100.0 150.0 200.0 250.0 300.0Time (s)

.75

.80

.85

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Void

Fra

ctio

n

WinGraf 4.1 - 08-17-2005

XXX RBMK_GDH_BLOCKAGE voidg214560000

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YYY RBMK_GDH_BLOCKAGE voidg259560000

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ZZZ RBMK_GDH_BLOCKAGE voidg265560000

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VVV RBMK_GDH_BLOCKAGE voidg669560000

V V V V V V V V V V V V V V V V V V

JJJ RBMK_GDH_BLOCKAGE voidg175560000

J J J J J J J J J J J J J J J J J

HHH RBMK_GDH_BLOCKAGE voidg244560000



Void fraction in affected FCs

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XXX RBMK_GDH_BLOCKAGE httemp214402101

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YYY RBMK_GDH_BLOCKAGE httemp259402201

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ZZZ RBMK_GDH_BLOCKAGE httemp265402001

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VVV RBMK_GDH_BLOCKAGE httemp669402001

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V V VV V V V V V V V V V V

JJJ RBMK_GDH_BLOCKAGE httemp175401801

J J JJ J J J J J J J J J J J J J

HHH RBMK_GDH_BLOCKAGE httemp244401201



Pressure Tubes temperature in affected FCs


•• FuelFuel ChannelChannel blockageblockage referencereference transienttransient forfor the the TACIS TACIS ProjectProject demonstrationdemonstration thatthat PressurePressure Tube Tube RuptureRupture doesdoes notnotpropagate propagate whatwhat happenshappens toto FC power?FC power?

1.50E+06

1.70E+06

1.90E+06

2.10E+06

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2.70E+06

2.90E+06

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Time (s)

Cha

nnel

Pow

er (W

)

Blocked_Channel

29-30

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30-30

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RELAP5-3D© FC Blockage

Power in blocked FC and neighbor FCs

0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0Time (s)

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WinGraf 4.1 - 09-26-2005

XXX RBMK_FC_BLOCKAGE httemp214400101

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YYY RBMK_FC_BLOCKAGE httemp214400201

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ZZZ RBMK_FC_BLOCKAGE httemp214400301

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Z

VVV RBMK_FC_BLOCKAGE httemp214400401

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JJJ RBMK_FC_BLOCKAGE httemp214400501

J JJ

JJ

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HHH RBMK_FC_BLOCKAGE httemp214400601

HH

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H

H H### RBMK_FC_BLOCKAGE httemp214400701

##

##

##

##

#

#OOO RBMK_FC_BLOCKAGE httemp214400801

OO

OO

OO

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O

O O

AAA RBMK_FC_BLOCKAGE httemp214400901

AA

AA

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BBB RBMK_FC_BLOCKAGE httemp214401001

BB

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B

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CCC RBMK_FC_BLOCKAGE httemp214401101

CC

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C

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DDD RBMK_FC_BLOCKAGE httemp214401201

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D

D D

EEE RBMK_FC_BLOCKAGE httemp214401301

EE

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FFF RBMK_FC_BLOCKAGE httemp214401401F

F F F

F

F F

GGG RBMK_FC_BLOCKAGE httemp214401501GG G G

G

G G

III RBMK_FC_BLOCKAGE httemp214401601II I I

I

I

LLL RBMK_FC_BLOCKAGE httemp214401701

L L L

L

L L

MMM RBMK_FC_BLOCKAGE httemp214401801

M M M

M

M

NNN RBMK_FC_BLOCKAGE httemp214401901

N N

N

N N

PPP RBMK_FC_BLOCKAGE httemp214402001

P P

P

P

QQQ RBMK_FC_BLOCKAGE httemp214402101Q Q

Q Q

RRR RBMK_FC_BLOCKAGE httemp214402201

R R

R

SSS RBMK_FC_BLOCKAGE httemp214402301

SS S

TTT RBMK_FC_BLOCKAGE httemp214402401

T T


Pressure Tube temp. in blocked FC


Power in blocked FC and neighbor FCs

ConclusionsConclusions

A detailed A detailed TH RBMK NPP nodalizationTH RBMK NPP nodalization was was developed developed RELAP5RELAP5--3D3D©© demonstrated capabilities in demonstrated capabilities in reproducing all TH phenomena of RBMK reproducing all TH phenomena of RBMK 3D NK model3D NK model was able to reproduce all reactor core was able to reproduce all reactor core peculiarities peculiarities good agreement with ingood agreement with in--core plant core plant datadataRELAP5RELAP5--3D3D©© (NESTLE)(NESTLE) -- HELIOSHELIOS constitutes an constitutes an independent and valid alternativeindependent and valid alternative toto Russian Russian system system codescodes KORSARKORSAR--BARSBARS--UNK (comparison executed)UNK (comparison executed)Future works in the framework of a PhD thesis: Future works in the framework of a PhD thesis: reproduction of transients at low power (e.g., reproduction of transients at low power (e.g., Chernobyl accident)Chernobyl accident)

Documents

Development of a 3D Neutron Kinetic-Thermal-hydraulic …...Development of a 3D Neutron Kinetic-Thermal-hydraulic Model for an RBMK Reactor by RELAP5-3D© CodeCode C. Parisi, M. Cherubini,