mox use in pwrs edf operation experiencerecycle/global2011/slides/pl-iv-3.pdftitle...

MOX use in PWRsEDF operation

experience

December 2011 - Global Copyright EDF

Jean-Luc ProvostNuclear Operation Division

EDF - Generation

1 – EDF back-end fuel cycle strategy

2 – Reactor adaptation for MOX fuel

3 – Fuel design and core management

Main itemsMain items

Global2011 – Japan - December 2011 Copyright EDF 2

4 – MOX fuel operation experience

5 – MOX fuel reliability

6 – EDF perspectives on MOX fuel

7 – Conclusions

1 1 –– EDF backEDF back--end fuel cycle strategyend fuel cycle strategy

At the end of 2010

58 units in operation (total installed capacity 63 GWe)(900 Mwe: 34 units, 1300 Mwe: 20 units, and 1500 Mwe: 4 units)

71000 FAs loaded in reactor (3500 MOX)


1230 cycles completed (300 cycles with MOX)

In 2010, EDF's generation : 476 TWh

Nuclear 408 TWh (86 %)Hydraulic 46 TWh (10 %)Fossil 22 TWh (4 %)

GR AVELINES6 N PP (5 M OX)

PEN LY2 N PPPA LU EL

4 N PP

FL AMA N VILL E2 N PP

SA IN T L AU R ENT

GR AVELINES6 N PP ( M OX)

PEN LY2 N PPPA LU EL

4 N PP

FL AMA N VILL E2 N PP

SA IN T L AU R ENT

D AMPIERR E4 N PP (4 M O X)

B ELLEVILLE2 N PP

C AT TEN OM4 N PP

N OGEN T SUR SEINE2 N PP

D AMPIERR E4 N PP (4 M O X)

B ELLEVILLE2 N PP

C AT TEN OM4 N PP

N OGEN T SUR SEINE2 N PP

C HO O Z2 N P P

C HO O Z2 N P P

EDF nuclear power plantsEDF nuclear power plants

Global2011 – Japan - December 2011 Copyright EDF4

C HINO N4 N PP (4 MOX)

SA IN T L AU R ENT2 NPP (

C HINO N4 N PP MOX)

SA IN T L AU R ENT2 NPP (2 MOX)

LE BU GEY4 N PP

SAINT A LB AN2 N PP

CR U AS4 NPP

G OLF ECH2 N PP

F ESSENH EIM2 N PP

LE B LAYA IS4 NPP (2 MOX)

2 MOX)

LE BU GEY4 N PP

SAINT A LB AN2 N PP

CR U AS4 NPP

G OLF ECH2 N PP

F ESSENH EIM2 N PP

LE B LAYA IS4 NPP (2 MOX)

C IVA UX2

C IVA UX2 NP P

TR IC A S TIN4 N P P (4 M O X )

9 00 M W P W R

1 300 M W P W R

1 450 M W P W R

The closed fuel cycle strategy , along with reprocessing and MOX recycling, enables today, with existing facilities :

• Stabilization of spent fuel quantity : with respect to underwater storage capacity - thanks to reprocessing and progress in fuel performance (average burn up increase)

• Vitrification of high level nuclear waste (fission products and actinides)

EDF backEDF back--end fuel cycle strategyend fuel cycle strategy


• Vitrification of high level nuclear waste (fission products and actinides) - a safe confinement under a reduced volume, internationally recognized,

• Recycling of plutonium- based on Pu flux equilibrium strategy : 120 tHM MOX/yr or 10 tHM Pu/yr recycled - MOX use produces 40 TWh/yr (or 9% of nuclear production)

• Preservation of long term energy resources- by concentration of Pu in MOX spent fuel under a reduced volume, full safeguard - leaves open the possibility to reuse Pu in future fast reactors (GEN IV)

Spent Fuel: 1200 tons /year (UOX et MOX)Recycling: MOX fuel

120 t/year on 22 units 900 MW --> 40 TWh/yr Spent Fuel

Transportation

UO2 Fuel fabrication ≈≈≈≈ 1000 t/year 2000 assemblies/yr (45 GWd/t average, max 52 GWd/t

Uranium and conversion≈≈≈≈ 8000 t/year

Enrichment≈≈≈≈ 5,5 MUTS/year

→→→→ time period 20 years

430 TWh /an

58 EDF NPPs22 units loaded with MOX4 units with ERU

EDF Nuclear fuel cycle strategyEDF Nuclear fuel cycle strategybased on the flux balance strategybased on the flux balance strategy


Reprocessing 1050 t/year

La Hague

MELOXFuel Fabricationplant

10 t/yr Separated plutonium (1%)

Reprocessed uranium: ~ 1000 t/yr(U235 content 0,8%) 540t re-enriched and recycled on 4 units 900W (100% core)or 80 t/yr ERU--> 30 TWh/yr

Vitrified High level Waste Interim passive storageDisposal optimisation

Transportation to La Hague, interim storage in cooling pools 1200 tons/year

120 m3/yr vitrified HLW

120 m3/yr compacted ILW

2 2 –– Reactor adaptation for MOX fuelReactor adaptation for MOX fuel

Reactivity control devices adapted

Due to higher energy neutron spectrum (higher Pu content)

Main adaptations : 8 RCCAs added, boron concentration increase

Fuel building adaptation Reinforcement of the crane (hardware and software)


Reinforcement of the crane (hardware and software)Direct storage under water in the fuel pit (dry storage forbidden) Visual examination by video camera of each MOX FA under waterReinforced safeguards on the plant (cameras in fuel building, …)

Fresh MOX fuel transport by MX8 cask ( design similar to spent fuel cask)To reduce the risk of excessive exposure of the operators during handlingTo improve transport safety and nuclear materials safeguardsUnloading currently under water, dry solution planed

Operators training (fuel handling, core monitoring)

3 3 –– Fuel design and core managementFuel design and core management

• MOX Fuel design

• MOX Fuel Assembly zoning

•


• MOX Parity core management

• Typical loading pattern

• Discharge burn-up

MOX fuel designMOX fuel design

Fuel type currently used : AREVA AFA-3G geometry M5 cladding and Zircaloy 4 structure

Use of depleted uranium (0,25% U235)To maximize the Pu concentration in FAs


Plutonium isotopic vectorMinimum fissile isotopes Pu139 + Pu141 : 63%MOX energy equivalence to UOX 3.7% � 8.65% Pu content

zoning : 3 Pu contents usedTo control the power distribution at MOX-UOX interface (high differences of fission cross-sections)

ZONE PERIPHERIQUE12 CRAYONS 2,3%Pu fissile

TUBED'INSTRUMENTATION

MOX AFA 3GMOX AFA 3G zoningzoning((averageaverage contentcontent : 8.65% max): 8.65% max)


ZONE INTERMEDIAIRE68 CRAYONS 6.5

1

%

ZONE CENTRALE184 CRAYONS 9.8 %

TUBE-GUIDE24 TUBES

CoreCore management management withwith MOXMOX

Recycling rate limited to 30% max (48 FAs/core)To maintain reactivity control devices efficiency (boron and RCCAs)

MOX Parity management (licensed in December 2006, implemented on


MOX Parity management (licensed in December 2006, implemented on 1 unit in 2007, 7 units in 2008, 17 units in 2009 and 20 units in 2010)

4-batch core management for MOX and UOXEach reload : 12 MOX (3.7% equivalent) + 28 UOX (3.7%)Pu content = 8.65% (fissile Pu: 63% total Pu)UOX average BU : 48 GWd/t (4 cycles) - max 50 GWd/t MOX average BU : 48 GWd/t (4 cycles) - max 50 GWd/t

� Parity of energy generated by UOX and MOX (after 4 annual cycles)

MOX Parity : typical loading patternMOX Parity : typical loading pattern

R P N M L K J H G F E D C B A

1 M

2

3 M M M M M M M

4 M M

5 M M M

6 M M M M M

7 M M


AC 1er cycle

AC 2ème cycle

AC 3ème cycle

AC 4ème cycle

7 M M

8 M M M M M M M M

9 M M

10 M M M M M

11 M M M

12 M M

13 M M M M M M M

14

15 M

UOX and MOX fuel discharged BU UOX and MOX fuel discharged BU EDF experience (2009EDF experience (2009--2010)2010)

150

200

250

Fue

l A

ssem

bly

num

ber

MOX & UOX discharge BU (2009-2010)


0

50

100

150

32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

Fue

l A

ssem

bly

num

ber

fuel assembly burn-up (GWd/t)

UOXMOX

4 4 –– feedback experience of MOX usefeedback experience of MOX use

• MOX use on EDF PWR units

• Core Physics measurements

•


• Load follow operation

• Environment impact

MOX use on PWR 900 MW unitsMOX use on PWR 900 MW units

22 PWR 900 MW units licensed to plutonium recycling1987 : Saint Laurent B1 (first unit opened to MOX)2008 : Gravelines 6 (21st unit opened to MOX)3500 FAs loaded which corresponds to 1600t MOX or 102t Pu recycled22nd unit Gravelines 5 will be open to MOX in 2012


Public inquiry launched in November 2011 for 2 new units with MOXNew Decree for Blayais 3 and 4 in 2012 : licensing in progress

EPR Flamanville 3an option with 30% MOX has been taken into account in the NSSS basis design

MOX FA loaded in PWR 900MWMOX FA loaded in PWR 900MW3500 MOX loaded # 102 3500 MOX loaded # 102 tHMtHM PuPu recycled (end 2010)recycled (end 2010)

150

200

250

300

MO

X F

A n

umbe

r

AFA 3G

AFA 2G


0

50

100

150

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

MO

X F

A n

umbe

r

year

AFA 2G

AFA

Core Physics measurementsCore Physics measurements

Core Physic start-up testsGood coherence between measurements and calculation

Boron concentration temperature coefficientRCCA rod worth

Core Physic measurements during periodic testsGood agreement between measurements and calculation


Good agreement between measurements and calculationFlux maps (incore instrumentation)Power picking factors

Conclusion : safety assessment calculations validat edSame uncertainties can be taken into account for UOX and MOX in the EDF safety reload demonstration (key parameters check-list)

� All EDF NPPs operated in load follow

� Frequency control (+/- 2%)

� Remote control (+/- 5%)

� Daily load follow (typically 6 hours at 50 % NP during the night)

� Extended low power operation (ELPO) during the week-end, and in summer

Operation experience : load followOperation experience : load follow


� Load follow experience with MOX

� Liquid waste volume decrease : 30% (due to Xenon effect)

� Ramp tests on MOX rods at Studvik

� better PCI behavior for MOX than for UOX

� No specific Technical Specifications for MOX

� CONCLUSION : no specific problem regarding plant operation with MOX

Operation experienceOperation experienceexample of a typical power history during a cycleexample of a typical power history during a cycle

80

100

120

% n

omin

al p

ower


0

20

40

60

16/10/01 24/01/02 04/05/02 12/08/02 20/11/02 28/02/03

% n

omin

al p

ower

no specific problem identified regarding plant oper ation with MOX

Environment : MOX impact on waste releaseEnvironment : MOX impact on waste release

•Waste release• Gaseous and liquid waste release are similar for MOX and UOXplants


plants• Iodine and Tritium releases equivalent

• waste release mainly due to fuel rod leakage history

LiquidLiquid wastewaste releaserelease

50

60

70

80

90

100

Act

ivit

y(M

Bq)

units 1&2units 3&4units 5&6Average PWR 900

Limit for two units = 300 MBq

20

25

30

35

40

Act

ivit

y(T

Bq)

units 1&2units 3&4units 5&6Average PWR 900

Limit for two units = 40 TBq


Iodine releaseUnits 1-4 used MOX fuel Units 5-6 used only UOX fuel

0

10

20

30

40

50

2002 2003 2004

Act

ivit

y

0

5

10

15

1998 1999 2000 2001 2002 2003 2004

Act

ivit

yTritium releaseUnits 1-4 used MOX fuel -Units 5-6 used only UOX fuel

GaseousGaseous releaserelease

0,30

0,40

0,50units 1&2units 3&4Average PWR 900

Limit for two units = 0,8 GBq

1,2

1,4

1,6

1,8

2,0units 1&2units 3&4Average PWR 900

Limit for two units = 4 TBq


Iodine releaseUnits 1-2 used MOX fuel Units 3-4 used only UOX fuel

0,00

0,10

0,20

2002 2003 20040,0

0,2

0,4

0,6

0,8

1,0

2002 2003 2004

Tritium releaseUnits 1-2 used MOX fuel Units 3-4 used only UOX fuel

5 5 -- MOX fuel reliability history (to end 2010)MOX fuel reliability history (to end 2010)

• 6 FA leakages from the origin : detected in operation by radio-chemistry analysis (discrimination based on Xe135/Kr85m)

• Dampierre 1 in 1993 (due to debris, reloaded)

• Tricastin 2 in 1997 (due to debris, repaired and reloaded)

• Tricastin 4 in 2001 (due to debris)

• Dampierre 1 in 2002 (at EOL, no examination)

• Dampierre 4 in 2009 (due to debris)




• CONCLUSION at end 2010 :

� 24 years of operation

� more than 300 reactor-years of experience

� good reliability of MOX, equivalent to UOX

MOX fuel reliability history (to end 2010)MOX fuel reliability history (to end 2010)

1,50

2,00

Fue

l as

sem

bly

failu

re r

ate

%

UOX and MOX Fuel failure rate on 900 MW units


0,00

0,50

1,00

1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Fue

l as

sem

bly

failu

re r

ate

%

Year

UOX Fuel

MOX Fuel

MOX impact on reactor operationMOX impact on reactor operationSummarySummary

No change regarding plant availability of the PWR 9 00MWe fleetSame annual cyclesLight increase of outage duration due to decay heat (Tpool<50°C)

No significant impact regarding operational maneuve rabilityBetter axial flux stability during power transients (reduced xenon efficiency)


Environment (liquid and gaseous waste release)reduced volume of effluents (30%) during power transients, similar gaseous and liquid waste release for MOX and UOX plants

No impact on Radioprotection Doses during outage mainly due to maintenancelow sensitivity to fuel (BU or Pu content)

6 6 -- EDF perspectives on MOX fuelEDF perspectives on MOX fuel

Plutonium isotopic vector has changed during these last 20 yearsThanks to evolution of core management and of fuel performanceSpent fuel burn-up has significantly increased (from 33 to 45 GWd/t)

Isotopic vector taken into account currently in MO X Parity core management Minimum fissile isotopes (Pu139 + Pu141) content : 63%Origin : UOX spent fuel BU = 43 GWd/t, stored 9 years before reprocessingSeparated Pu stored 3 years before MOX manufacturing


Available UOX spent fuel to be reprocessed during t he next decade:Increased BU > 46 GWd/t, stored more than 10 years (Pu139 decrease)Longer time of separated Pu storage before manufacturing (Am141 increase)Main consequence : isotopic vector degradation to 61% fissile isotope

To maintain UOX 3.7% equivalence, total Pu content needs to be increase from 8.65% to 9.5%

Each accidental transient of SAR has to be re-assessed and to be reviewed by the French Regulator

7 7 -- Main ConclusionsMain Conclusions

• The large EDF experience of 24 years with MOX is globally satisfactory (plant safety and availability, fuel reliability, environment and radioprotection),


• From 2007, implementation of MOX Parity fuel management achieves the balance of MOX and UOX fuel performance and contributes to stabilize the amount of separated plutonium

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