Development of Np and Am bearing MOX fuels for Japan ... · Am, Np (count/sec) Pu Am Np Central...

Japan Atomic Energy Agency

Plutonium Fuel Development Facility

Masato KATO

Development of Np and Am bearing MOX fuels for Japan sodium cooled fast reactors

Fuel Technology R&D SectionPlutonium Fuel Development CenterNuclear Fuel Cycle Engineering LaboratoriesJapan Atomic Energy Agency


Masato KATO


2


－－－－ Development of MOX containing MA －－－－

Hollow MOX pellets

Pellets of (Np0.02Am0.02Pu0.3U0.64)O2

Background

Specification of the fuel pelletType : Hollow type Pu content : 20 - 30%MA content : ~ 5%(Np+Am+Cm)Density : 95%TDO/M : ＜＜＜＜1.97

1. Database and models for properties

2. Advanced fabrication process

3. Analysis code of irradiation behaviour of low O/M MA-MOX pellet

� Japan Atomic Energy Agency has developed homogeneous mixed oxide containing minor actinides (MA-MOX) for Japan sodium-cooled fast reactors.

Subjects to be carried out

3


－－－－ Development of MOX containing MA －－－－Background

１. Property Measurements・Thermodynamic data・Thermal properties・Chemical properties

2. Pellet Fabrication Test・Homogenization・O/M adjustment Technology・Sintering behavior

3. Irradiation test・Actinide redistribution・Microstructure change・FCCI

Experimental evaluation




� Japan Atomic Energy Agency has developed homogeneous mixed oxide containing minoractinides (MA-MOX) for Japan sodium-cooled fast reactors.


4


－－－－ Development of MOX containing MA －－－－Background

１. Property Measurements・Thermodynamic data・Thermal properties・Chemical properties

2. Pellet Fabrication Test・Homogenization・O/M adjustment Technology・Sintering behaviour

3. Irradiation test・Actinide redistribution・Microstructure change・FCCI

Purpose of this workTo analysis PIE results by using the measured data to develop an analysis code.

Experimental evaluation� Japan Atomic Energy Agency has developed homogeneous mixed oxide containing minoractinides (MA-MOX) for Japan sodium-cooled fast reactors.





5


Contents1. Irradiation Test and PIE Results

2.Properties of the fuel pellets

3.Analysis of Irradiation behaviour

•Irradiation condition•Microstructure changes•Actinides redistribution•Evaluation of properties

Lattice parameter, Meting temperatureThermal conductivity, Oxygen potential

•O/M redistribution•Relation between Pu redistribution and vapour pressure•Evaluation of microstructure change

6

Plutonium Fuel Development FacilityIrradiation test

200m m

1500

mm

Fuel Pin

MA-MOX

MOX

Condition 1

Irradiation pattern

Held for 10min at 430W/cm

MA-MOX (Np0.016Am0.016Pu0.3U0.668)Oy 1.98MOX (Pu0.3U0.7)Oy 1.98

Composition O/M Pin No. Name

No.1-1

First Test

O/M=1.98

Pin No.1-1

MA-MOX

MOX

Time

7

Plutonium Fuel Development FacilityIrradiation test

Fuel Pins

MA-MOX

MOX

Second Test

O/M=1.98 , 1.96

MA-MOX (Np0.016Am0.016Pu0.3U0.668)Oy 1.98MOX (Pu0.3U0.7)Oy 1.98

Condition 2

Composition O/M

Irradiation pattern

Pin No.

200m m

1500

mm

Pin No.2-1

Pin No.2-1

Name

No.2-1

No.2-2 MA-MOX (Np0.016Am0.016Pu0.3U0.668)Oy 1.96MOX (Pu0.3U0.7)Oy 1.96

Held for 24h at 430W/cm

8

Plutonium Fuel Development FacilityPIE Results Microstructure Change

No.1-1 MA-MOX, O/M=1.98, at 427W/cm for 10 min

1.The heat rate of the fuels attained about 430W/cm.

2.The pellets were unmelted.

3.Pores migrated to the center.

4.Columnar grain and central void were observed

Central voidColumnar grain

Central void

Columnar grain


Observation results

No.2-1 MA-MOX, O/M=1.98, at 432W/cm for 24h


9


0

1000

2000

3000

4000

5000

6000

7000

8000

0.0 0.5 1.0 1.5 2.0 2.5Radius（mm）

Pu (c

ount/

sec)

0

200

400

600

800

1000

1200

1400

Am, N

p (co

unt/s

ec)

PuAmNp

Central void

0

1000

2000

3000

4000

5000

6000

7000

8000

0.0 0.5 1.0 1.5 2.0 2.5Radius（mm）

Pu (c

ount/

sec)

0

200

400

600

800

1000

1200

1400

Am, N

p (co

unt/s

ec)

PuAmNp

Central void

Actinide Redistribution

1.The content of Puand Am increased at pellet center.

2.The increment of Pu and Am decreased with decreasing O/M.

3.The contents of Npand U were flat.

Observation results


N0.2-2 MA-MOX, O/M=1.96, at 429W/cm for 24h

PuAm

Np

Pu

AmNp

PIE Results

10


Lattice Parameter

5.40

5.42

5.44

5.46

5.48

5.50

1.80 1.85 1.90 1.95 2.00 2.05

B

C

MOX

MA-MOX

Lattic

e para

meter

; a (A

)

O/M

o

(U

1-y

Pu

y

)O

2.00

(U

0.96-y

Pu

y

Am

0.02

Np

0.02

)O

2.00

Properties of fuel pellets (1/4)

Lattice Parameter vs. O/M ratio

1.The model to represent the lattice parameter was derived.

2.MA content slightly caused the lattice parameters to decrease.

3.The difference of theoretical density is 0.01-0.02g/cm3.

Results

))112.01((3/4 ac rxra ++=)"')"'1(( yryrzryyzrr NpAmPuUc +++−−−=

M.Kato, et al.,J.N.M.385 (2009) 117

11


Melting Temperature

3000

3020

3040

3060

3080

3100

0 1 2 3 4

Temp

eratur

e (K)

3000

3020

3040

3060

3080

3100

0 0. 0. 0. 0. 0. 0. 0 . 0.

3000

3020

3040

3060

3080

3100

0 0. 0. 0. 0. 0. 0. 0. 0.

Am+Np content (Am/Np=1)2.00

1.98O/M

Liquidus

1.96Solidus

Properties of fuel pellets (2/4)

Variation of Solidus and Liquidus Temp.

1.The data were measured and analyzed by the ideal solid solution model.

2.MA content caused to decrease by 2-3K /%MA.

3.The solidus temperature of MA-MOX is over 3000K.

Results

M.Kato, et al.,ICAPP ‘09

12

Plutonium Fuel Development FacilityProperties of fuel pellets (3/4)

0

1

2

3

4

5

0 500 1000 1500 2000 2500

BCDE

Therm

al co

nduc

tivity

;λ0(W

/mK)

Temperature (K)

MOXMA-MOX

O/M=1.98

O/M=1.96

Thermal conductivity

1.The data were measured as functions of MA content, density, O/M and temperature.

2.MA content caused to decrease slightly in temperatures of less than 1000K.

Results


( ) ( ) Txx 42- 2

2-1

1-0 10493.22.625-101.595 z106.317 z103.583 2.7131

−×++×+××+××+=λ

××+

TT

4

2/5

11 10522.1exp10541.1

z1: Am contentz2: Np content x:Deviation x in MO2-x

M.Kato, et al., OECD/NEA, Oct. 6-10, 2008, Japan

13

Plutonium Fuel Development FacilityProperties of fuel pellets (4/4)

-700

-600

-500

-400

-300

-200

1200 1400 1600 1800 2000

CDBC

Oxyg

en po

tentia

l (kJ/m

ol)

Temperature (K)

O/M=1.98

O/M=1.96

MOX

MA-MOX

Oxygen potential

Oxygen potential

1.The data were measured by gas equilibrium method.

2.MA content caused the oxygen potential to increase slightly.

Results

M.Kato, et al.,J.N.M. 385 (2009) 419

14

Plutonium Fuel Development FacilityProperties of fuel pellets (4/4)Oxygen potential

1.The data were measured by gas equilibrium method.

2.MA content caused the oxygen potential to increase slightly.

Results

Oxygen potential

SummaryThe effect of MA addition on the properties is negligibly small in the operation temperature range of FR fuels

-700

-600

-500

-400

-300

-200

1200 1400 1600 1800 2000

CDBC

Oxyg

en po

tentia

l (kJ/m

ol)

Temperature (K)

O/M=1.98

O/M=1.96

MOX

MA-MOX

15


Analysis ProcedureInput

Vapour pressure


Lattice parameter

-Vapour pressure-Oxygen potential

Results- Temperature- O/M ratio

TemperatureO/M redistribution

Migration rate of pore2.Relation between vapourpressure and Pu redistribution

3.Evaluation of microstructure change

1.Comparison with Melting temperature

Analysis of irradiation behaviour

DimensionDensityO/M ratioLinear heat rateCoolant temperature

16


Input

Vapour pressure

Lattice parameter







Analysis Procedure



17




Input

Vapour pressure

Lattice parameter







Analysis Procedure

18


Input

Vapour pressure

Migration rate of pore

Lattice parameter



2.Relation between vapourpressure and Pu redistribution



1.Comparison with melting temperature

Analysis Procedure



19


Input

Vapour pressure


Lattice parameter







Analysis ProcedureDimensionDensityO/M ratioLinear heat rateCoolant temperature

20


O/M Redistribution

1.80

1.85

1.90

1.95

2.00

2.05

0.0 0.5 1.0 1.5 2.0 2.5 3.0

O/M=1.98O/M=1.96O/M=1.98O/M=1.96

O/M

Distance from cladding inner surface (mm)

Sari's modelAitken's model

O/M ratio distribution in the radial direction

Results 1.Both models gave

almost the same result in high O/M pellets.

2.The results of low O/M pellets differed according to models.

3.Sari’s model was employed.

21


10

-5

10

-4

10

-3

10

-2

10

-1

10

0

10

1

0.0 0.5 1.0 1.5 2.0 2.5 3.0

O/M=1.98

O/M=1.96

P (Pu

-spec

ies)/P

(U-sp

ecies

)

Composition of the pellet


Evaluation of vapour pressure

Variation of vapor pressure

10-35

10-30

10-25

10-20

10-15

10-10

10-5

0.0 0.5 1.0 1.5 2.0 2.5 3.0

UUOUO2UO3PuPuOPuO2AmO2AmO

Vapo

ur pre

ssure

(atm

)

Distance from pellet surface(mm)

Variation of Pu-/U- species

Result1.Variation of vapor pressure ratio of Pu/U-species

was evaluated using Rand –Markin model.

22


Evaluation of Pu redistribution

0.1 1.0 10.0

0

5

10

15

20

MOX

MA-MOX

MOX

MA-MOX

F

MOX

MA-MOX

MOX

MA-MOX

PPu-species/PU-species ratio

Amount of Pu increase (wt%)

O/M=1.98

O/M=1.96


Sari's model

： Pu/U ~ 0.3/0.7

U increasePu increase

0.4

Result1.Calculation result shows that U content increases

at pellet center.

23


0.1 1.0 10.0

0

5

10

15

20

MOX

MA-MOX

MOX

MA-MOX

F

MOX

MA-MOX

MOX

MA-MOX



O/M=1.98

O/M=1.96


Sari's model

： Pu/U ~ 0.3/0.7


?


0.4

ExpectationIncrement of Pu should be increased with decreasing the PPu-species/PU-species.

24


0.1 1.0 10.0

0

5

10

15

20

MOX

MA-MOX

MOX

MA-MOX

F

MOX

MA-MOX

MOX

MA-MOX



O/M=1.98

O/M=1.96


Sari's modelO/M=1.98

O/M=1.96

Author's correction

： Pu/U ~ 0.3/0.7



Results1.Calculation results show that Pu content increase at pellet centre.

2.Two lines were obtained depending on O/M ratio.

0.4

O/M=1.96O/M=1.98

25


Reviewing of the model for O/M redistributionSari’s model for O/M redistribution

−∗=

122

1 11ln TTRQ

xx

2455 105.81066.51045.9 PuPu VVQ ×−×+×−=∗

X: deviation in (U,Pu)O2-xT： temperatureR ：gas constant,Q* ：：：： the molar effective heat of transport VPu ： Pu valence

0

10000

20000

30000

40000

3.23.43.63.84.0

C

D

-Q

*

(cal/mol)

V

Pu

Sari's model

This work

Evaluation of equation for Q*

Calculation of O/M Redistribution, temperature and vapour pressure

Evaluation of the relationship between the PPu-species/PU-speciesand the Pu increase

Corrected Eq.352666 107122.1107705.1101012.61001.7 PuPuPu VVVQ ×−×−×+×−=∗

26


Sari’s model for O/M redistribution

−∗=

122

1 11ln TTRQ

xx

2455 105.81066.51045.9 PuPu VVQ ×−×+×−=∗

X: deviation in (U,Pu)O2-xT： temperatureR ：gas constant,Q* ： the molar effective heat of transportVPu ： Pu valence

Evaluation of equation for Q*

Calculation of O/M Redistribution, temperature and vapour pressure

Evaluation of the relationship between the PPu-species/PU-speciesand the Pu increase

Reviewing of the model for O/M redistribution

Corrected Eq.352666 107122.1107705.1101012.61001.7 PuPuPu VVVQ ×−×−×+×−=∗

0.1 1.0

0

5

10

15

20




Sari's model

Author's correction

27


Calculation results in MA-MOX pellets

1000

1500

2000

2500

3000

0.0 0.5 1.0 1.5 2.0 2.5 3.0

O/M=1.98O/M=1.96

Temp

eratur

e (K)


(a) Temperature

1.90

1.95

2.00

2.05

0.0 0.5 1.0 1.5 2.0 2.5 3.0

O/M=1.98O/M=1.96

O/M


(b) O/M ratio

0.0

1.0

2.0

3.0

4.0

5.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0

O/M=1.98O/M=1.96

Therm

al co

nduc

tivity

(W/cm

K)


(c) Thermal conductivity

10-310-210-1100

101

102

0.0 0.5 1.0 1.5 2.0 2.5 3.0

O/M=1.98O/M=1.96P (

Pu-sp

ecies

)/P(U

-spec

ies)



(d) Vapour pressure ratio

Temperature Thermal conductivity

O/M ratio Vapour pressure ratio of Pu-/U-species

28


3.0

3.2

3.4

3.6

3.8

4.0

2000 2200 2400 2600 2800 3000

MOXMA-MOXMOXMA-MOX

Diam

eter o

f colu

mnar

grain

region

(mm)

Temperature at pellet center (K)

O/M=1.98O/M=1.96

0.0

0.5

1.0

1.5

2000 2200 2400 2600 2800 3000

MOXMA-MOXMOXMA-MOX

Diam

eter o

f cen

tral v

oid (m

m)

O/M=1.98O/M=1.96

Temperature at pellet centre (K)


Results1.The both region grew with temperature.2.The central void of high O/M pellet is larger than

that of low O/M pellets.

Columnar grain region Central void

Microstructure change

O/M=1.96O/M=1.98

29


Summary1.The physical properties of the Np/Am-MOX were evaluated, and the effect of Np/Am addition was negligiblｙｙｙｙ small.

2.The relation between the Pu redistribution and the vapor pressure was described by correcting Sari’s model for O/M redistribution.

3.The low O/M pellet attained higher temperature, however, the diameter of the central void was small as compared with the high O/M pellet.

4. It is needed to measure experimental data and to derive advanced models for describing irradiation behavior of low O/M fuel.

Japan Atomic Energy Agency


Masato KATO




Masato KATO


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Development of Np and Am bearing MOX fuels for Japan ... · Am, Np (count/sec) Pu Am Np Central...

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