(1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 0 |...

(1) Die Kooperation von Forschungszentrum Karlsruhe GmbH

und Universität Karlsruhe (TH)1 |

Transient Analysis for the EFIT 3-Zone CoreTransient Analysis for the EFIT 3-Zone Core

P. Liu, P. Liu, X.-N. ChenX.-N. Chen, A. Rineiski, S. Wang, M. Flad, W. Maschek, A. Rineiski, S. Wang, M. Flad, W. Maschek

Forschungszentrum Karlsruhe, IKETForschungszentrum Karlsruhe, IKETPostfach 3640, D-76021 KarlsruhePostfach 3640, D-76021 Karlsruhe

IP EUROTRANS DM1 WP1.5 Mtg. Bologna, 28-30 May 2008

IP EUROTRANS DM1IP EUROTRANS DM1



ContentsContents

Design base and Some former work;Design base and Some former work; (ULOF, Beam trip, UTOP, UBA already presented in last meeting)(ULOF, Beam trip, UTOP, UBA already presented in last meeting)SIMMER-III new model;SIMMER-III new model; (with a new implemented pump model)(with a new implemented pump model) ULOF ULOF (under new pressure drop conditions);(under new pressure drop conditions); Beam Trip Beam Trip (short term beam trip:1second);(short term beam trip:1second);Unprotected Blockage Unprotected Blockage (first fuel ring totally blocked);(first fuel ring totally blocked); SummariesSummaries



ENEA 384MWth 3Zone Core DesignENEA 384MWth 3Zone Core Design

42 66 72

Lower gas plenum

Upper gas plenum

Fuel pellets

Lower insulator

Upper insulator

Bottom plug

Top plug

9.52

40

845

15

15

900

265

20

2100

Output section

Hex. wrapper

Fuel bundle

Central rod

Joint section

186

Ø159

4080

70

2100

485

26

160

1220

Ø146

Ø127

4.0

18613

.63

186

Ø127

186

Ø12

186

Input tube

“Conical”foot

Output section

Hex. wrapper

Fuel bundle

Central rod

Joint section

186

Ø159 18

6

Ø159

4080

70

2100

485

26

160

1220

Ø146

Ø127

Ø 146

Ø127

4.0

18613

.63

4.0

18613

.63

186

Ø127

186

186

Ø127

186

Ø12

186

Ø12

186

Input tube

“Conical”foot



Former work-SIMMER-III simulation of the steady state

SIMMER-IIISIMMER-IIISIMMER-IIISIMMER-III

0

250

500

750

1000

1250

1500

1750

2000

1 2 3 4 5 6ring

pcm Worth/Ring BoCWorth/Ring EoC ENEAENEA



SIMMER-III Calculated SIMMER-III Calculated Peak Fuel Temperature: Peak Fuel Temperature: 1352.1 1352.1 ℃℃;; Peak Clad Temperature: Peak Clad Temperature: 521.1 521.1 ℃℃

SIMMER-III Calculated SIMMER-III Calculated Peak Fuel Temperature: Peak Fuel Temperature: 1352.1 1352.1 ℃℃;; Peak Clad Temperature: Peak Clad Temperature: 521.1 521.1 ℃℃

Limit temperatures at nominal conditions: Fuel 1380 ℃℃, Clad 550 ℃℃; (From ENEA Files)Limit temperatures at nominal conditions: Fuel 1380 ℃℃, Clad 550 ℃℃; (From ENEA Files)

Former work-SIMMER-III simulation of the steady state



New geometrical model of EFIT core in SIMMER-IIINew geometrical model of EFIT core in SIMMER-III

Coolant outlet Coolant outlet Coolant outlet Coolant outlet

Coolant inletCoolant inletCoolant inletCoolant inlet

Coolant flow passCoolant flow pass Coolant flow passCoolant flow pass

Pump regionPump regionPump regionPump region

Heat exchangerHeat exchanger

regionregion

Heat exchangerHeat exchanger

regionregion

NewNew



ULOF analysisULOF analysis

Assumptions and conditions: Core - SG midplane distance: 3.7 m; Core - SG midplane distance: 3.7 m; The transient starts at 60 s from a The transient starts at 60 s from a

well established steady-state;well established steady-state; Total pressure drop in the primary Total pressure drop in the primary

system system 1.1 bar;1.1 bar; 1.37 bar (two cases);1.37 bar (two cases); 1.87 bar;1.87 bar; Pump head becomes zero in 10 s; Pump head becomes zero in 10 s;

halving time = 2 s; (Main) halving time = 2 s; (Main) Pump head becomes zero in 5s, Pump head becomes zero in 5s,

halving time =2 s; halving time =2 s; (for the 2(for the 2ndnd case of 1.37bar) case of 1.37bar)

Assumptions and conditions: Core - SG midplane distance: 3.7 m; Core - SG midplane distance: 3.7 m; The transient starts at 60 s from a The transient starts at 60 s from a

well established steady-state;well established steady-state; Total pressure drop in the primary Total pressure drop in the primary

system system 1.1 bar;1.1 bar; 1.37 bar (two cases);1.37 bar (two cases); 1.87 bar;1.87 bar; Pump head becomes zero in 10 s; Pump head becomes zero in 10 s;

halving time = 2 s; (Main) halving time = 2 s; (Main) Pump head becomes zero in 5s, Pump head becomes zero in 5s,

halving time =2 s; halving time =2 s; (for the 2(for the 2ndnd case of 1.37bar) case of 1.37bar)



ULOF analysis -1.1 bar pressure dropULOF analysis -1.1 bar pressure drop

Pump head becomes zero in 10 s,Pump head becomes zero in 10 s, halving time =2 s halving time =2 s




ULOF analysis -1.37 bar pressure drop (1ULOF analysis -1.37 bar pressure drop (1stst case) case)





ULOF analysis -1.37 bar pressure drop (1st case)ULOF analysis -1.37 bar pressure drop (1st case)

Simple view of Simple view of the the Coolant Coolant

MovementMovement in the in the system during system during

the pump coast the pump coast down process.down process.

Simple view of Simple view of the the Coolant Coolant

MovementMovement in the in the system during system during

the pump coast the pump coast down process.down process.



ULOF analysis -1.37 bar pressure drop (2ULOF analysis -1.37 bar pressure drop (2ndnd case) case)


PPump coast down data needed!!ump coast down data needed!!


PPump coast down data needed!!ump coast down data needed!!



ULOF analysis -1.87 bar pressure dropULOF analysis -1.87 bar pressure drop





ULOF-ComparisonULOF-Comparison



Beam trip analysisBeam trip analysis Assumption: External beam amplitude being zero for 1 second.External beam amplitude being zero for 1 second. Assumption: External beam amplitude being zero for 1 second.External beam amplitude being zero for 1 second.

Maximum Maximum fuelfuel temp. temp. decrease aboutdecrease about 554 K 554 K;;

Maximum clad Maximum clad temperature decrease temperature decrease

about about 14 K;14 K; Maximum coolant Maximum coolant

temperature decrease temperature decrease about about 12 K.12 K.

Maximum Maximum fuelfuel temp. temp. decrease aboutdecrease about 554 K 554 K;;

Maximum clad Maximum clad temperature decrease temperature decrease

about about 14 K;14 K; Maximum coolant Maximum coolant

temperature decrease temperature decrease about about 12 K.12 K.

Fuel temp. at core Fuel temp. at core mid-plane;mid-plane;

Coolant and clad Coolant and clad temp. at core outlettemp. at core outlet

Fuel temp. at core Fuel temp. at core mid-plane;mid-plane;

Coolant and clad Coolant and clad temp. at core outlettemp. at core outlet



Unprotected blockageUnprotected blockage

Assumptions/Conditions/Parameters:Assumptions/Conditions/Parameters: Innermost ring totally blocked Transient starts at 30 s from a well established steady-state; He & fission gas pressure (1MPa BOC initial at gas plenum) Radial heat exchange between SA rings is taken into account; Clad failure and gas release at 1280K; Clad weakening and start of fuel movement at 1513 K Hexcan crack at 1280K; Hexcan weakening at 1513K; Fuel particle size volumetrically equals to one pellet: r = 4.555mm; Steel particle size r = 2.0mm; No-removable upper pin structure; No damage propagation to Target facility;

Assumptions/Conditions/Parameters:Assumptions/Conditions/Parameters: Innermost ring totally blocked Transient starts at 30 s from a well established steady-state; He & fission gas pressure (1MPa BOC initial at gas plenum) Radial heat exchange between SA rings is taken into account; Clad failure and gas release at 1280K; Clad weakening and start of fuel movement at 1513 K Hexcan crack at 1280K; Hexcan weakening at 1513K; Fuel particle size volumetrically equals to one pellet: r = 4.555mm; Steel particle size r = 2.0mm; No-removable upper pin structure; No damage propagation to Target facility;



Unprotected blockage-ContinuedUnprotected blockage-Continued

Power increased to a Power increased to a maximum of maximum of 655 MW655 MW;;

Fuel pin damage Fuel pin damage propagation happens, propagation happens, damage spreads to the damage spreads to the third fuel ring.third fuel ring.

Power increased to a Power increased to a maximum of maximum of 655 MW655 MW;;

Fuel pin damage Fuel pin damage propagation happens, propagation happens, damage spreads to the damage spreads to the third fuel ring.third fuel ring.



Summaries

ULOF AnalysisULOF Analysis New SIMMER modeling on the ULOF has been performed with a New SIMMER modeling on the ULOF has been performed with a

pump and heat exchange region and in turn, pump and heat exchange region and in turn, the three free surface the three free surface well modeled with the implemented pump model in SIMMER-IIIwell modeled with the implemented pump model in SIMMER-III;;

Under the 1.37 bar total pressure drop and the assumed pump coast Under the 1.37 bar total pressure drop and the assumed pump coast down conditions, the current core can survive the ULOF transient;down conditions, the current core can survive the ULOF transient;

Pump coast down data should be well establishedPump coast down data should be well established;;

Beam Trip AnalysisBeam Trip Analysis With a 1 seconds beam-off, the maximum fuel temperature With a 1 seconds beam-off, the maximum fuel temperature

decreases about decreases about 554 K554 K, the maximum clad temperature transiently , the maximum clad temperature transiently decreases decreases 14 14 KK, the maximum coolant temperature decreases , the maximum coolant temperature decreases 12 12 KK;;

UBA AnalysisUBA Analysis Fuel damage could happen and spread to the third fuel ring if the first fuel ring Fuel damage could happen and spread to the third fuel ring if the first fuel ring

is completely blocked;is completely blocked; The power can arrive as high as The power can arrive as high as 655 MW655 MW;; The power finally decreases due to the inherent fuel sweep-out mechanism.The power finally decreases due to the inherent fuel sweep-out mechanism.

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