EUROTRANS – DM1 Preliminary Transient Analysis for EFIT with RELAP5 and RELAP/PARCS Codes WP5.1 Progress Meeting Empresarios Agrupados - Madrid, November

ENTE PERLE NUOVE TECNOLOGIE,L’ENERGIA E L ’AMBIENTE


EUROTRANS – DM1

Preliminary Transient Analysis for EFIT with RELAP5 and

RELAP/PARCS Codes

WP5.1 Progress MeetingEmpresarios Agrupados - Madrid, November 13-14, 2007

G. Bandini, P. Meloni, M. Polidori

FPN-FISNUC / Bologna

OUTLINE

RELAP5 Thermal-Hydraulic Model Improvements and EFIT Parameters

List of Transients to be Analyzed by ENEA

Sensitivity Study to Pump Inertia (ULOF)

Definition of Reactor Trip Set-Points

Results of Protected Transients with RELAP5

Analysis of Unprotected Transients with RELAP/PARCS



Empresarios Agrupados – Madrid, November 13-14, 2007, EUROTRANS – DM1 – WP1.5 Progress Meeting

RELAP5 Model Improvements




22

112

173

UPPER PLENUMbranch120

110

LOWER PLENUMbranch 100

176 (177/8/9)175

6282

171

branch 160

Jun 106

InnerAverage

151

152153154

111

InnerHot

210211

OuterHot

OuterAverage

pipe281

282/3/4

SGswater side

Pumps113

DHR

Pth

pumpsplenumbranch

121

SGsPb side

SGsPb side

pipe381

382/3/4

annulus181

182/3/4

311310109

CoreMiddle

AverageMiddle

Hot

By pass&

reflector

branch

branchbranch

branch

03 010204050607

07 06 05 04 0203 01

01

01 0101

02

Jun 63Jun 23 Jun 83

Jun 104 Jun 114

01

05

06

01 02

22

112

170


110


176 (177/8/9)175

6282

171

branch 160

Jun 106

InnerAverage

152153154

111

InnerHot

210211

OuterHot

OuterAverage

pipe281

282/3/4

SGswater side

113

DHR

Pth

SGsPb side

pipe381

382/3/4

annulus181

182/3/4

311310109

CoreMiddle

AverageMiddle

Hot

By pass&

reflector

branch

branchbranch

branch

03 010204050607

07 06 05 04 0203 01

01 0101

02

Jun 63Jun 23 Jun 83

Jun 104 Jun 114

01

05

06

01 02

0101

0108

108

Tar

get

lo

op

102

161

Jun 105

08

102

161

Jun 105

08

22

112

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110


176 (177/8/9)175

6282

171

branch 160

Jun 106

InnerAverage

151

152153154

111

InnerHot

210211

OuterHot

OuterAverage

pipe281

282/3/4

SGswater side

Pumps113

DHR

Pth

pumpsplenumbranch

121

SGsPb side

SGsPb side

pipe381

382/3/4

annulus181

182/3/4

311310109

CoreMiddle

AverageMiddle

Hot

By pass&

reflector

branch

branchbranch

branch

03 010204050607

07 06 05 04 0203 01

01

01 0101

02

Jun 63Jun 23 Jun 83

Jun 104 Jun 114

01

05

06

01 02

22

112

170


110


176 (177/8/9)175

6282

171

branch 160

Jun 106

InnerAverage

152153154

111

InnerHot

210211

OuterHot

OuterAverage

pipe281

282/3/4

SGswater side

113

DHR

Pth

SGsPb side

pipe381

382/3/4

annulus181

182/3/4

311310109

CoreMiddle

AverageMiddle

Hot

By pass&

reflector

branch

branchbranch

branch

03 010204050607

07 06 05 04 0203 01

01 0101

02

Jun 63Jun 23 Jun 83

Jun 104 Jun 114

01

05

06

01 02

0101

01080108

108

Tar

get

lo

op

102

161

Jun 105

08

102

161

Jun 105

08

RELAP5 Nodalization Scheme

Update of steam generator model and secondary side boundary conditions

Primary mechanical pump model added effect of pump inertia in LOF transients

Core pressure drop (grid spacer model added)

Target loop and power removal added

Upper plenum mesh refinement recirculation flows according to SIMMER-III results




Primary circuit layout from ANSALDO presentation at the last EUROTRANS - DM4 Technical Review Meeting (March 2007): Reactor core with 3 fuel zones 4 primary pumps, 8 steam generators, 4 secondary loops 4 DHR units (3 out of 4 in operation in transient analysis)

Primary circuit parameters: Reactor thermal power = 395.2 MW Lead mass flowrate = 33230 kg/s Core inlet / outlet temperature = 400 / 480 C Total primary circuit pressure drop = 1.1 bar

(core = 0.45 bar, SG = 0.35 bar, Pump + others = 0.3 bar )

Secondary circuit parameters: Total feedwater flow rate (4 SGs) = 244.4 kg/s, Temperature = 335 C Steam pressure = 140 bar Steam temperature = 452 C (Superheating of 115 C)

EFIT Design and Parameters

Nominal Conditions: RELAP5 Steady-State




Maximum temperature

(°C)

Inner zone (Fax = 1.14)

Middle zone (Fax = 1.16)

Outer zone (Fax = 1.17)

Hot FA 1/42

Fr = 1.12

Average FA 41/42

Hot FA 1/66

Fr = 1.13

Average FA 65/66

Hot FA 1/72

Fr = 1.24

Average FA 71/72

Central fuel 1251 1150 1328 1213 1285 1094

Surface fuel 869 818 857 804 816 735

Internal clad 538 523 534 519 535 509

External clad 527 513 524 509 526 501

Lead 494 484 494 483 503 483

Parameter Inner zone

Middle zone

Outer zone

Reflector + by-pass

Target Total

Thermal power (MW) 96 142.3 140.5 5.2 11.2 395.2

Lead mass flow rate (kg/s) 7707 11548 11345 1120 1512 33232

By-pass

outlet

Target

outlet

- -

- -

- -

- -

431 450

List of Transients to be Analyzed by ENEA (1)




TRANSIENT TO BE ANALYZED FOR PB-COOLED EFIT DESIGN

Number Transient Description BOC EOCENEA

RELAP5 (X-S) RELAP/PARCS (X-C)

SIMMER

PROTECTED TRANSIENTS

P-1 PLOFTotal loss of forced

circulation in primary system (4 pumps)

x xX-S (reactor trip on

core outlet temp. threshold)

P-1.1 PLOF-1Loss of 1 out of 4

primary pumps (pump rotor seizure)



P-4 PLOHTotal loss of secondary

loops (4 loops)x x

X-S (reactor trip on core outlet temp.

threshold)

P-4.1 PLOH-1loss of 1 out of 4 secondary loops



P-5PLOF + PLOH

(station blackout)

Total loss of forced circulation and secondary loops

x xX-S (reactor trip

at 0 s)X (reactor trip at 0 s)

P-10Spurious beam

tripbeam trip for 1,2,3 …..

10 s intervalsx x X-C

P-11 SGTRSteam generator tube rupture (1 to 5 tubes)

xX (reactor trip at 0 s)

List of Transients to be Analyzed by ENEA (2)




TRANSIENT TO BE ANALYZED FOR PB-COOLED EFIT DESIGN

Number Transient Description BOC EOCENEA

RELAP5 (X-S) RELAP/PARCS (X-C)

SIMMER

UNPROTECTED TRANSIENTS

U-1 ULOF

Total loss of forced circulation in

primary system (4 pumps)

x x X-C X

U-2 UTOP(?) pcm jump in

reactivity at HFPx x X-C

U-4 DEC ULOHTotal loss of

secondary loops(4 loops)

x x X-C

U-5 DECULOF + ULOH

Total loss of forced circulation and secondary loops

x x X-C

U-11Beam

Overpower to (?)% at HFP

x x X-C

U-12Beam Power

Jump to 100% at HZP

x x X-C




Preliminary Analysis of Protected Transients

P-1 – PLOF: Total loss of forced circulation in primary system (4 pumps)

P-1.1 – PLOF-1: Loss of 1 out 4 primary pumps (pump rotor seizure)

P-4 – PLOH: Loss of all secondary loops

P-4.1 – PLOH-1: Loss of 1 out of 4 secondary loops

P-5 – PLOF + PLOH (Station blackout): Total loss of forced circulation and secondary loops and beam trip

REACTOR TRIP: Proton beam switch-off if average core outlet temperature > Threshold set-point (primary pump trip??, actions on secondary side??)

Sensitivity Study to Pump Inertia (ULOF) (1)




-20

-10

0

10

20

0 5 10 15 20 25 30

Time (s)

Vel

ocity

(ra

d/s)

Inertia = 20

Inertia = 50

Inertia = 100

Inertia = 200

Pump Velocity

-5000

-2500

0

2500

5000

7500

10000

0 5 10 15 20 25 30

Time (s)

Flo

w r

ate

(kg/

s)

Inertia = 20

Inertia = 50

Inertia = 100

Inertia = 200

Pump Mass Flow Rate Unprotected Loss of Flow accident analysis (4 pumps lost)

Pump inertia varying in the range 20 – 200 kg*m2

Primary pumps stop in few seconds

High pump reverse flow is induced by free level movements

Sensitivity Study to Pump Inertia (ULOF) (2)




Inlet Core Mass Flow Rate

Maximum Clad Temperature Core mass flow rate oscillations induced by free level movements

Lowest undershoot for pump inertia in the range 50 – 100 kg*m2

No significant effect of pump inertia on maximum clad temperature peak

Largest value of pump inertia is not favorable

-10000

0

10000

20000

30000

40000

0 5 10 15 20 25 30

Time (s)

Flo

w r

ate

(kg/

s)

Inertia = 20

Inertia = 50

Inertia = 100

Inertia = 200

700

800

900

1000

1100

1200

0 5 10 15 20 25 30

Time (s)

Tem

pera

ture

(K

)

Inertia = 20

Inertia = 50

Inertia = 100

Inertia = 200

Definition of Reactor Trip Set-Points (1)




Threshold set-point on measured lead temperature (top assembly, upper plenum average core outlet, pump inlet)

2 2

1 1 2

1 7 3

U P P E R P L E N U Mb r a n c h 1 2 0

1 1 0

L O W E R P L E N U Mb r a n c h 1 0 0

1 7 6 ( 1 7 7 / 8 / 9 )1 7 5

6 28 2

1 7 1

b r a n c h 1 6 0

J u n 1 0 6

I n n e rA v e r a g e

1 5 1

1 5 21 5 31 5 4

1 1 1

I n n e rH o t

2 1 02 1 1

O u t e rH o t

O u t e rA v e r a g e

p i p e2 8 1

2 8 2 / 3 / 4

S G sw a t e r s i d e

P u m p s1 1 3

D H R

P t h

p u m p sp l e n u mb r a n c h

1 2 1

S G sP b s i d e

S G sP b s i d e

p i p e3 8 1

3 8 2 / 3 / 4

a n n u l u s1 8 1

1 8 2 / 3 / 4

3 1 13 1 01 0 9

C o r eM i d d l e

A v e r a g eM i d d l e

H o t

B y p a s s&

r e f l e c t o r

b r a n c h

b r a n c hb r a n c h

b r a n c h

0 3 0 10 20 40 50 60 7

0 7 0 6 0 5 0 4 0 20 3 0 1

0 1

0 1 0 10 1

0 2

J u n 6 3J u n 2 3 J u n 8 3

J u n 1 0 4 J u n 1 1 4

0 10 5

0 6

0 1 0 2

2 2

1 1 2

1 7 0


1 1 0


1 7 6 ( 1 7 7 / 8 / 9 )1 7 5

6 28 2

1 7 1

b r a n c h 1 6 0

J u n 1 0 6


1 5 21 5 31 5 4

1 1 1

I n n e rH o t

2 1 02 1 1

O u t e rH o t


p i p e2 8 1

2 8 2 / 3 / 4


1 1 3

D H R

P t h

S G sP b s i d e

p i p e3 8 1

3 8 2 / 3 / 4

a n n u l u s1 8 1

1 8 2 / 3 / 4

3 1 13 1 01 0 9

C o r eM i d d l e


H o t

B y p a s s&

r e f l e c t o r

b r a n c h


b r a n c h

0 3 0 10 20 40 50 60 7

0 7 0 6 0 5 0 4 0 20 3 0 1

0 1 0 10 1

0 2

J u n 6 3J u n 2 3 J u n 8 3

J u n 1 0 4 J u n 1 1 4

0 10 5

0 6

0 1 0 2

0 10 1

0 10 8

1 0 8

Ta

rg

et

loo

p

1 0 2

1 6 1

J u n 1 0 5

0 8

1 0 2

1 6 1

J u n 1 0 5

0 8

2 2

1 1 2

1 7 3


1 1 0


1 7 6 ( 1 7 7 / 8 / 9 )1 7 5

6 28 2

1 7 1

b r a n c h 1 6 0

J u n 1 0 6


1 5 1

1 5 21 5 31 5 4

1 1 1

I n n e rH o t

2 1 02 1 1

O u t e rH o t


p i p e2 8 1

2 8 2 / 3 / 4


P u m p s1 1 3

D H R

P t h


1 2 1

S G sP b s i d e

S G sP b s i d e

p i p e3 8 1

3 8 2 / 3 / 4

a n n u l u s1 8 1

1 8 2 / 3 / 4

3 1 13 1 01 0 9

C o r eM i d d l e


H o t

B y p a s s&

r e f l e c t o r

b r a n c h


b r a n c h

0 3 0 10 20 40 50 60 7

0 7 0 6 0 5 0 4 0 20 3 0 1

0 1

0 1 0 10 1

0 2

J u n 6 3J u n 2 3 J u n 8 3

J u n 1 0 4 J u n 1 1 4

0 10 5

0 6

0 1 0 2

2 2

1 1 2

1 7 0


1 1 0


1 7 6 ( 1 7 7 / 8 / 9 )1 7 5

6 28 2

1 7 1

b r a n c h 1 6 0

J u n 1 0 6


1 5 21 5 31 5 4

1 1 1

I n n e rH o t

2 1 02 1 1

O u t e rH o t


p i p e2 8 1

2 8 2 / 3 / 4


1 1 3

D H R

P t h

S G sP b s i d e

p i p e3 8 1

3 8 2 / 3 / 4

a n n u l u s1 8 1

1 8 2 / 3 / 4

3 1 13 1 01 0 9

C o r eM i d d l e


H o t

B y p a s s&

r e f l e c t o r

b r a n c h


b r a n c h

0 3 0 10 20 40 50 60 7

0 7 0 6 0 5 0 4 0 20 3 0 1

0 1 0 10 1

0 2

J u n 6 3J u n 2 3 J u n 8 3

J u n 1 0 4 J u n 1 1 4

0 10 5

0 6

0 1 0 2

0 10 1

0 10 80 10 8

1 0 8

Ta

rg

et

loo

p

1 0 2

1 6 1

J u n 1 0 5

0 8

1 0 2

1 6 1

J u n 1 0 5

0 8

Upper plenum

Pump

2 2

1 1 2

1 7 3


1 1 0


1 7 6 ( 1 7 7 / 8 / 9 )1 7 5

6 28 2

1 7 1

b r a n c h 1 6 0

J u n 1 0 6


1 5 1

1 5 21 5 31 5 4

1 1 1

I n n e rH o t

2 1 02 1 1

O u t e rH o t


p i p e2 8 1

2 8 2 / 3 / 4


P u m p s1 1 3

D H R

P t h


1 2 1

S G sP b s i d e

S G sP b s i d e

p i p e3 8 1

3 8 2 / 3 / 4

a n n u l u s1 8 1

1 8 2 / 3 / 4

3 1 13 1 01 0 9

C o r eM i d d l e


H o t

B y p a s s&

r e f l e c t o r

b r a n c h


b r a n c h

0 3 0 10 20 40 50 60 7

0 7 0 6 0 5 0 4 0 20 3 0 1

0 1

0 1 0 10 1

0 2

J u n 6 3J u n 2 3 J u n 8 3

J u n 1 0 4 J u n 1 1 4

0 10 5

0 6

0 1 0 2

2 2

1 1 2

1 7 0


1 1 0


1 7 6 ( 1 7 7 / 8 / 9 )1 7 5

6 28 2

1 7 1

b r a n c h 1 6 0

J u n 1 0 6


1 5 21 5 31 5 4

1 1 1

I n n e rH o t

2 1 02 1 1

O u t e rH o t


p i p e2 8 1

2 8 2 / 3 / 4


1 1 3

D H R

P t h

S G sP b s i d e

p i p e3 8 1

3 8 2 / 3 / 4

a n n u l u s1 8 1

1 8 2 / 3 / 4

3 1 13 1 01 0 9

C o r eM i d d l e


H o t

B y p a s s&

r e f l e c t o r

b r a n c h


b r a n c h

0 3 0 10 20 40 50 60 7

0 7 0 6 0 5 0 4 0 20 3 0 1

0 1 0 10 1

0 2

J u n 6 3J u n 2 3 J u n 8 3

J u n 1 0 4 J u n 1 1 4

0 10 5

0 6

0 1 0 2

0 10 1

0 10 8

1 0 8

Ta

rg

et

loo

p

1 0 2

1 6 1

J u n 1 0 5

0 8

1 0 2

1 6 1

J u n 1 0 5

0 8

2 2

1 1 2

1 7 3


1 1 0


1 7 6 ( 1 7 7 / 8 / 9 )1 7 5

6 28 2

1 7 1

b r a n c h 1 6 0

J u n 1 0 6


1 5 1

1 5 21 5 31 5 4

1 1 1

I n n e rH o t

2 1 02 1 1

O u t e rH o t


p i p e2 8 1

2 8 2 / 3 / 4


P u m p s1 1 3

D H R

P t h


1 2 1

S G sP b s i d e

S G sP b s i d e

p i p e3 8 1

3 8 2 / 3 / 4

a n n u l u s1 8 1

1 8 2 / 3 / 4

3 1 13 1 01 0 9

C o r eM i d d l e


H o t

B y p a s s&

r e f l e c t o r

b r a n c h


b r a n c h

0 3 0 10 20 40 50 60 7

0 7 0 6 0 5 0 4 0 20 3 0 1

0 1

0 1 0 10 1

0 2

J u n 6 3J u n 2 3 J u n 8 3

J u n 1 0 4 J u n 1 1 4

0 10 5

0 6

0 1 0 2

2 2

1 1 2

1 7 0


1 1 0


1 7 6 ( 1 7 7 / 8 / 9 )1 7 5

6 28 2

1 7 1

b r a n c h 1 6 0

J u n 1 0 6


1 5 21 5 31 5 4

1 1 1

I n n e rH o t

2 1 02 1 1

O u t e rH o t


p i p e2 8 1

2 8 2 / 3 / 4


1 1 3

D H R

P t h

S G sP b s i d e

p i p e3 8 1

3 8 2 / 3 / 4

a n n u l u s1 8 1

1 8 2 / 3 / 4

3 1 13 1 01 0 9

C o r eM i d d l e


H o t

B y p a s s&

r e f l e c t o r

b r a n c h


b r a n c h

0 3 0 10 20 40 50 60 7

0 7 0 6 0 5 0 4 0 20 3 0 1

0 1 0 10 1

0 2

J u n 6 3J u n 2 3 J u n 8 3

J u n 1 0 4 J u n 1 1 4

0 10 5

0 6

0 1 0 2

0 10 1

0 10 80 10 8

1 0 8

Ta

rg

et

loo

p

1 0 2

1 6 1

J u n 1 0 5

0 8

1 0 2

1 6 1

J u n 1 0 5

0 8

Upper plenum

Pump

Clad safety limits for categories DBC II – DBC IV (PDS-XADS):• Tclad max ≤ 823 K with

• time ≤ 600 s at 823 – 873 K

• time ≤ 180 s at 873 – 923 K

ULOH Temperature

Threshold set-point at 773 K on average core outlet temperature limits the maximum clad temperature at 823 K

700

750

800

850

900

950

0 20 40 60 80 100 120

Time (s)

Tem

pera

ture

(K

)

Top assemblyupper plenumpump inletMaximum clad

Threshold set-point at 773 K

Reactor trip

Definition of Reactor Trip Set-Points (2)




700

750

800

850

900

950

0 10 20 30 40 50 60

Time (s)

Tem

pera

ture

(K

)

Top assembly

upper plenum

pump inlet

Maximum clad

Threshold set-point at 773 KReactor trip

600

700

800

900

1000

1100

1200

0 10 20 30 40 50 60

Time (s)

Tem

pera

ture

(K

)

Top assembly

upper plenum

pump inlet

Maximum clad


Reactor trip

ULOF Temperature

ULOF (1 Pump) Temperature

The clad safety limit of 823 K is exceeded by 15 K in case of 1 pump trip event and threshold set-point at 773 K on average core outlet temperature

In case of all primary pumps trip the high clad temperature peak cannot be limited by lead temperature threshold on average core outlet temperature




700

750

800

850

900

950

0 100 200 300 400 500 600

Time (s)

Tem

pera

ture

(K

)

Top assemblyupper plenumpump inletMaximum clad


Reactor trip

Actions on Primary and Secondary sides are in general needed after automatic proton beam trip to bring the plant in safe conditions and avoid lead overcooling

Actions Following Proton Beam Trip

ULOH (1 Loop) Temperature Primary pump trip

Turbine and feedwater trip

The results of different actions and timing have been evaluated for the initiating event of loss of 1 secondary loop

Beam trip at 120 s when core outlet temperature > 773 K

Actions Following Beam Trip (Short Term)




Action Primary pump trip Turbine and feedwater trip

1 Never Never

2 At proton beam trip Never

3 30 s after beam trip Never

4 30 s after beam trip 30 s after beam trip

600

650

700

750

800

850

0 100 200 300 400 500

Time (s)

Tem

pera

ture

(K

)

Action 1Action 2Action 3Action 4

600

650

700

750

800

850

0 100 200 300 400 500

Time (s)

Tem

pera

ture

(K

)


Maximum Clad TemperatureInlet Core Temperature

Loss of 1 Secondary Loop

Actions Following Beam Trip (Long Term)




Action Primary pump trip Turbine and feedwater trip

1 Never Never

2 At proton beam trip Never

3 30 s after beam trip Never

4 30 s after beam trip 30 s after beam trip

Maximum Clad TemperatureInlet Core Temperature

Loss of 1 Secondary Loop

600

650

700

750

800

850

0 1000 2000 3000 4000 5000

Time (s)

Tem

pera

ture

(K

)


600

650

700

750

800

850

0 1000 2000 3000 4000 5000

Time (s)

Tem

pera

ture

(K

)


Preliminary Analysis of Protected Transients




INITIATING EVENTS: PLOF-1: Loss of 1 out 4 primary pumps

PLOF: Total loss of forced circulation in primary system

PLOH-1: Loss of 1 out of 4 secondary loops

PLOH: Loss of all secondary loops

PLOF + PLOH (Station blackout): Total loss of forced circulation and secondary loops and beam trip

REACTOR TRIP: Proton beam trip if average core outlet temperature > 773 K

Primary pump trip at beam trip

No actions on secondary side

PLOF-1: Loss of 1 Primary Pump (1)




Primary Pump Mass Flow Rate Inlet Core Mass Flow Rate

Pump 2,3,4 stop(Reactor trip)

Pump 2,3,4 stop(Reactor trip)

Pump 1 lost

Steady-state at 5000 s (primary pump 1 lost with reverse flow)

Pump 2, 3 , 4 stop at reactor trip after about 10 s

PLOF-1: Loss of 1 Primary Pumps (2)




Lower and Upper Plenum Temperature Maximum Lead Temperature

Reactor trip (T > 773 K)

T max = 839 K(hot channel of outer core)

Reactor trip 10 s after pump 1 stop (T > 773 K)

Maximum lead temperature is 839 K in the hot channel of outer core zone






T max = 1620 K(hot channel of middle core)

Maximum Fuel TemperatureMaximum Clad Temperature

Maximum clad temperature exceeds the limit of normal conditions (823 K) but is below the clad safety limit for DBC1- 4 transient conditions (923 K)

Limited fuel temperature increase (below 1620 K)





Primary Pump 2, 3, 4 Trip 30 s after Beam Trip

Pump 2,3,4 stop(30 s after reactor trip)

T max = 838 K

Pump 1 lost

Primary Pump Mass Flow Rate Maximum Clad Temperature

Clad temperature peak is limited by delaying primary pump shutdown (30 s) with respect to proton beam switch-off

Beam trip

PLOF: Loss of All Primary Pumps (1)




Primary Pump Mass Flow Rate Inlet Core Mass Flow Rate

Pump mass flow rate reverses just after stopping (negligible effect of pump inertia)

Initial oscillations of inlet core mass flow rate are due to free level movements and stabilization





Reactor Trip

Reactor trip about 10 s after pump trip (average lead temp. at core outlet > 773 K)

Large temperature peak due to initial core mass flow rate undershoot

The maximum lead temperature remains well below the boiling point (1476 K)

Lower and Upper Plenum Temperature Maximum Lead Temperature






T max = 1700 K(hot channel of middle core)

T max = 1080 K(hot channel of inner core)

Maximum Fuel TemperatureMaximum Clad Temperature

Maximum clad temperature exceeds for few seconds the limit of 923 K for DBC1 – 4 transient conditions

The maximum fuel temperature is 1700 K in the hot channel of middle core zone

PLOH-1: Loss of 1 Secondary Loop (1)




0.E+00

1.E+08

2.E+08

3.E+08

4.E+08

5.E+08

0 100 200 300 400 500

Time (s)

Po

we

r (W

)

Core powerSG power

0

10000

20000

30000

40000

0 100 200 300 400 500

Time (s)

Flo

w r

ate

(kg

/s) mflowj 100080000

600

650

700

750

800

0 100 200 300 400 500

Time (s)

Te

mp

era

ture

(K

)

Lower plenum

Upper plenum

Inlet Core Mass Flow Rate

Upper and Lower Plenum Temp.

Core and SG Power


Pump trip at beam trip

Reactor trip at 120 s (T lead > 773 K, beam and pump trip)




PLOH-1: Loss of 1 Secondary Loop (2)

Maximum Fuel Temperature

600

800

1000

1200

1400

1600

1800

0 100 200 300 400 500

Time (s)

Te

mp

era

ture

(K

)

ave (in core)ave (mid core)ave (out core)hot (in core)hot (mid core)hot (out core)

Maximum Clad Temperature

650

700

750

800

850

900

0 100 200 300 400 500

Time (s)

Te

mp

era

ture

(K

)

ave (in core)ave (mid core)ave (out core)hot (in core)hot (mid core)hot (out core)Maximum Lead Temperature

650

700

750

800

850

900

0 100 200 300 400 500

Time (s)

Te

mp

era

ture

(K

)


Lead and clad temperature peaks can be avoided with pump trip delay

Maximum clad temperature peak is within the safety limit for DBC1 – 4 transient conditions

T max = 860 K

T max = 865 K

PLOH: Loss of All Secondary Loops (1)




Inlet Core Mass Flow RateLower and Upper Plenum Temperature

Reactor trip (proton beam switch-off and pump stop) after 43 s (T lead > 773 K)

Large oscillation of lead mass flow rate at core inlet due to free level movements


Pump trip





Lower and Upper Plenum TemperatureCore and DHR Power

Maximum DHR performance (3 units) = 20 MW is attained after about 5000 s

Maximum lead temperature stabilizes after about 5000 s at 723 K





Maximum Vessel TemperatureMaximum Clad Temperature

Maximum clad temperature is 877 K in the hot channel of outer core zone (no peak with delayed pump trip)

Vessel temperature (maximum after about 3000 s) remains below the safety limit (723 K)

T max = 877 K(hot channel of outer core) T max = 722 K

PLOF + PLOH: Station Blackout (1)




Core and DHR Mass Flow Rate

Core and DHR Inlet/Outlet Temp.

Core and DHR Power

650

680

710

740

770

800

-2000 0 2000 4000 6000 8000 10000

Time (s)

Te

mp

era

ture

(K

)

Core inlet

Core outlet

DHR inlet

DHR outlet

0.0E+00

5.0E+06

1.0E+07

1.5E+07

2.0E+07

2.5E+07

3.0E+07

-2000 0 2000 4000 6000 8000 10000

Time (s)

Po

we

r (W

)

Core power

DHR power

0

1000

2000

3000

4000

5000

-2000 0 2000 4000 6000 8000 10000

Time (s)

Flo

w r

ate

(kg

/s)

Core inlet

DHR inlet

Natural circulation mass flow rate in primary system and DHR power removal confirmed by SIMMER-III 2-D results

DHR mass flow rate in good agreement with ANSALDO specifications at 3600 s (2985 kg/s)





Maximum Fuel Temperature

600

800

1000

1200

1400

1600

1800

-50 0 50 100 150 200 250

Time (s)

Te

mp

era

ture

(K

)


Maximum Lead Temperature

700

730

760

790

820

850

-50 0 50 100 150 200 250

Time (s)

Te

mp

era

ture

(K

)


T max = 844 K


700

730

760

790

820

850

-50 0 50 100 150 200 250

Time (s)

Te

mp

era

ture

(K

)


T max = 848 K

Maximum clad temperature is within the safety limit for DBC1 – 4 transient conditions (time ≤ 600 s at 823 – 873 K)






Maximum Vessel Temperature

Maximum Lead Temperature

700

730

760

790

820

850

-2000 0 2000 4000 6000 8000 10000

Time (s)

Te

mp

era

ture

(K

) ave (in core)ave (mid core)ave (out core)hot (in core)hot (mid core)hot (out core)

700

730

760

790

820

850

-2000 0 2000 4000 6000 8000 10000

Time (s)

Te

mp

era

ture

(K

)


650

670

690

710

730

-2000 0 2000 4000 6000 8000 10000

Time (s)

Te

mp

era

ture

(K

)httemp 100100201

httemp 100100401

httemp 100100601

T limit = 723 K

T max = 715 K

Maximum lead and clad temperatures stabilize around 730 K

Maximum vessel temperature remains below the safety limit

Documents

EUROTRANS – DM1 Preliminary Transient Analysis for EFIT with RELAP5 and RELAP/PARCS Codes WP5.1 Progress Meeting Empresarios Agrupados - Madrid, November