Experimental Evaluation of Am and Np Bearing Mixed Oxide ... · 05 10 15 MA Content (%) 29%Pu...

Japan Atomic Energy Agency

Plutonium Fuel Development Facility

Experimental Evaluation of Am and Np Bearing

Mixed Oxide Fuel Properties

M. Kato, K. Morimoto, A. Komeno, S. Nakamichi, M. Kashimura

Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency


－ Development of MOX containing MA －

Japan Atomic Energy Agency has developed homogeneous mixed oxide containing minor actinides (MA-MOX) as a fuel of the advanced fast reactor.

Specification of the fuel pelletType : Hollow type Pu content : 20 - 30%MA content : - 5%(Np+Am+Cm)

Density : 93%TDO/M ： 1.95Burn-up : 150GWd/t

Hollow pellets of MOX

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

Background

Physical property measurements of Am and Np bearing MOXThe effect of MA addition on the physical properties


Outline

Sample preparation

Phase state and Phase separation

Lattice parameters

Oxygen potentials

Melting temperatures

Thermal conductivities


Sample preparation

Ball mill

Starting materials

Press

Sintering

Annealing for MO2.00

Annealing to adjust O/M ratio

Measurement

UO2, (U,Pu)O2, (U,PuNp)O2, (Pu,Am)O2

at 1923-1973K for 3-4 h in 5%H2/Ar flowing gas added moisture

at 1123K for 4 h in the atmosphere of ΔG=-400-420kJ/mol

at 1123-1973K for 3-25 h in an appropriate atmosphere


Sample preparation List of samples

Composition Sample Name U(%) Pu(%) Np(%) Am(%) O/M MOX-1 MOX-2 6%Np-MOX 12%Np-MOX 2.4%Am-MOX 2%Np/Am-MOX 1.8%Np/Am-MOX 12%Pu-MOX 20%Pu-MOX-1 20%Pu-MOX-2 MOX-3 40%Pu-MOX-1 40%Pu-MOX-2 40%Pu-MOX-3 43%Pu-MOX 46% Pu-MOX 60% Pu-MOX 2%Am-PuO2 6%Am-PuO2 7%Am-PuO2

70.3 69.5 64.3 58.3 67.6 66

66.4 87.9 79.7 78.7 69.6 59.6 58.5 58.4 53.7 51.4 37.7

29 30 29 29 30 30 30

11.8 19.9 19.8 29.8 39.7 39.6 38.3 42.8 46.3 60

97.9 93.6 94

6 12 2

1.8

0.7 0.5 0.7 0.7 2.4 2

1.8 0.3 0.4 1.5 0.6 0.7 1.9 3.3 3.5 2.4 2.3 2.1 6.4 7.2

2.00-1.9092.00-1.9242.00-1.9142.00-1.9092.00-1.9512.00-1.9232.00-1.9192.00-1.9712.00-1.9422.00-1.947

2.00 2.00-1.9162.00-1.961

2.00 2.00

2.00-1.7182.00 2.00 2.00 2.00

(U1-z-y’-y“Pu z Amy’Np y”)O2.00-x

Pu : Z = 0 – 97.9%Am : y’ = 0.5 – 7.2%Np : y” = 0 – 12%x : x = 0 – 0.282(O/M=2.00 – 1.718)


Homogeneity of samples

0

100

200

300

400

500

600

700

110 115 120 125 130 135 140 145

2θ

Intensity

0

100

200

300

400

500

600

700

800

900

1000

110 115 120 125 130 135 140 145

２θ

Intensity

X-ray diffraction pattern

EPMA analysis on cross section(U0.668Pu 0.3 Am0.016Np 0.16)O2.00 (U0.537Pu 0.428 Am0.035)O2.00

SEM U Pu

Am Np

SEM U Pu

Am


Phase State at room temperature

Phase diagram in U-Pu-O system at R.T.

1.60

1.70

1.80

1.90

2.00

2.10

0 20 40 60 80 100

fcc single phaseTwo pahases

O/M Two phases

Pu content (%)

Single phase

0

200

400

600

800

1000

1200

２θ

Intensity

0

100

200

300

400

500

600

110 115 120 125 130 135 140 145

2θ

Intensity

Two fcc Phases

Single fcc Phase

Sari et al.


Phase Separation Behavior

50μm

(a) (b)

(c)

(d)(c)

(a)(Pu0.3U0.7)O1.927(b)(Pu0.3Np0.06U0.64)O1.92(c) (Pu0.3Np0.016Am0.016U0.68)O1.92(d) (Pu0.3Am0.024U0.636)O1.921

MOX 6%Np-MOX

Am/Np-MOX Am-MOX

300

400

500

600

700

800

0 5 10 15 20

MOX6%Np-MOX12%Np-MOX1.8%Np/Am-MOX2.4%Am-MOX

Phas

e se

para

tion

tem

pera

ture

(K )

MA content (%)

MOX-Np

MOX-Np/AmMOX-Am

O/M=1.91-1.93

The effect of MA content on the phase separation temperature.

No effect of phase separation on the fuel properties.


Lattice parameters

5.42

5.43

5.44

5.45

5.46

5.47

0 5 10 15MA Content (%)

29%Pu

40%Pu

Am/Np-MOXNp-MOXAm-MOX

Calculation

Am/Np-MOX

Np-MOXAm-MOX

Experiment

Latti

ce p

aram

eter

(A)o

Np

Am

The lattice parameters decrease with MA content, and increase with decreasing the O/M.The derived model represent the experimental data very well.

Np/Am

5.42

5.44

5.46

5.48

5.50

5.52

1.7 1.75 1.8 1.85 1.9 1.95 2 2.05

12%Pu-MOX20%Pu-MOX-120%Pu-MOX-26%Np-MOX12%Np-MOXMOX-11.8%Np/Am-MOX2%Np/Am-MOX40%Pu-MOX46%Pu-MOX

30%Pu-MOX

Latti

ce p

aram

eter

(A)

O/M

Reference[11]


Oxygen potentials Experiments

0.43

0.44

0.45

0.46

0.47

10-14

10-13

10-12

10-11

10-10

500 1000 1500 2000 2500 3000

at 1573K

TG(m

g)

PO2(a

tm)

Time(s)

TG

PO2

15 min

FM

Gｌoｖe Box

Air Damper

Oxygen sensor

Oxygen sensor220cc/min

Gas Mixer

TG-DTA (Rigaku TG8120 model )Measurement Temperature : ～1400℃Thermo Gravimetry

Horizontal differential type balanceAccuracy of the weight measurement : ±1μg

(O/M :±0.00015)

Sample

Reference(Al2O3)200cc/min

MFC MFC

He/0.05%

H2

He/5%

H2

He

20cc/min

Instrument adding water vapor

Gas System1～2000ppmH2O0.01～5%H2

TG-DTA

Horizon type TG-DTA was employed in the measurement.

The oxygen partial pressure was controlled by controlling the ratio of PH2/PH2O and measured with stabilized ZrO2 oxygen sensors.

The change of TG attained to equilibrium condition for about 15min.

The O/M ratio was calculated from the weight change.

The O/M ratio and PO2 were measured with good repeatability and precision.

Schematic diagram of measurement system

Measurement results


Oxygen potentials

-800

-600

-400

-200

0

1000 1200 1400 1600 1800 2000Δ

GO

2 (kJ/mol

)

Temperature (K)

(U0.8

Pu0.2

)O1.995

(U0.7

Pu0.3

)O1.995

(U0.9

Pu0.1

)O1.995

(U0.6

Pu0.4

)O1.995

Besmann et al.

10%Pu

40%Pu

(U0.66

Pu0.3

Am0.02

Np0.02

)O1.995

AmO1.995

(Thiriet and Konings)

20%Pu

30%Pu

NpO1.995

(Bartscher and Sari)

(U0.65

Pu0.3

Am0.045

)O1.995

(Osaka et al.)

(U0.656

Pu0.32

Am0.024

)O1.995

1.96 1.97 1.98 1.99 2.00 2.01-500

-450

-400

-350

-300

-250

1623K1573K1473K1623K1573K1473KHIJ

O/M

ΔGo 2(k

J/m

ol)

(U,Pu,Np,Am)O2-X

(U0.7

Pu0.3

)O2-X

[12]O/M=1.995

The ΔGO2 of (U,Pu,Am,Np)O2-X are slightly higher than those of MOX without MA. The slightly higher ΔGO2 is caused by Am content.

The change of the ΔGO2 Comparison of the ΔGO2 of MO1.995

Measurement Results


2500

2600

2700

2800

2900

3000

0 100 200 300 400 500Elapsed time

Tem

pera

ture

(°C

)

Melting temperatures

2200 2400 2600 2800 3000 3200 34002200

2400

2600

2800

3000

3200

3400

Melting point measuered in this work (K)

Mel

ting

poin

t (K

)

Ta

Mo

Nb

Al2O

3

Temperature calibration by standard samples

Solidus

Liquidus

Thermal arrest

Heating temperature curve of MOX

Specimen

Induction heating furnace

Two-color pyrometer for control

Two-color pyrometer for measurement

Experiments

Re inner

W capsule

Sample


2800

2900

3000

3100

3200

0 10 20 30 40 50

SolidusReSolidusSolidusSolidus

mol% PuO2

Tem

pera

ture

(K)

This work W capsule

Latta and Fryxell [7]Aitken and Evans [8]

Lyon and Baily [6]

Re inner

Solidus Temperatures depending on Pu content

The data measured by conventional method were in good agreement with other data, and the measured value fell off at about 30%Pu –MOX.

The reaction between MOX and W was observed in the measured samples with 30% and 40%Pu content.

Melting Temperatures


2800

2900

3000

3100

3200

0 10 20 30 40 50

SolidusReSolidusSolidusSolidus

mol% PuO2

Tem

pera

ture

(K)

This work W capsule

Latta and Fryxell [7]Aitken and Evans [8]

Lyon and Baily [6]

Re inner

Solidus Temperatures depending on Pu content

The data measured by conventional method were in good agreement with other data, and the measured value fell off at about 30%Pu –MOX.

The reaction between MOX and W was observed in the measured samples with 30% and 40%Pu content.

The solidus measured with Re-capsule are consistent with that of MOX with Pu content of less than 20%.

It can be concluded that the solidus temperature measured by using Re inner is true melting temperature of MOX



UO2-PuO2 system

Melting TemperaturesUO2- PuO2 system and effect of MA addition

2900

2950

3000

3050

3100

3150

0 10 20 30 40 50

DRe inner capsuleW capsule

Pu content (%)

Tem

pera

ture

(K)

Solid

Liquid

(a)

Am content : 0-3.3%

0 2 4 6

NpAmNp/AmNpAmNp/Am38-42%Pu

MA content (%)

Solid

Liquid

=1

40%Pu

(b)

Experiment

Calculated by Eqs.(1)-(7)

Am-MOX

-4K/1%Am


Measurement apparatus

Fig.1 Thermal diffusivity measurement apparatus.

Thermal diffusivity (α) measurement : Laser flash method

Infrared detector

W mesh heater

Mirror

Specimen

Temperature control system

and Power supplyThermocouple

Glove box

•High temperature furnaceResistance heating furnace

•Temperature-measuring deviceW-Re thermo couple

•Laser sourceNd glass Laser Maximum output 17 J / Pulse

•Infrared detectorInSb sensing device （~1673 K）

(Hamamatsu Photonics K.K. ) Si sensing device （1673 K ~）

(Tokyo Seiko co. )

Preamplifier and High speed memory

PC & monitor

t = 0 point monitor

Controller andPower supply

Laser Head

Thermal conductivity


Dependency of density

Porosity dependency of thermal conductivities on 2%Am-MOX

1

2

3

4

5

6

0.00 0.05 0.10 0.15 0.20

Porosity

Ther

mal

con

duct

ivity

(W/m

/K)

873K Obs.1073K Obs.1273K Obs.1473K Obs.1673K Obs.873K calc.1673K calc.

873K

1673K


Porosity (density) correction equation of λ is described as follows.In this section, correction coefficient(β) is determined.

0λλ ×= F

λ0 : The value of MOX specimen with theoretical density (100%TD)

λ : The experimental value of MOX specimen with porosity p

F : Porosity correction equation (Maxwell-Eucken equation)

β : Correction coefficient p : Porosity (p = 1-(ρ / ρth) )

ρ : Density of specimenρth : Theoretical density of specimen

( )( )p

pF×+

−=

β11

F : Maxwell-Eucken equation

β =0.5


1

2

3

4

5

6

800 1000 1200 1400 1600 1800Temperature (K)

Ther

mal

con

duct

ivity

(W/m

/K) 6%Np-MOX

12%Np-MOX0.7%Am-MOX 2%Am-MOX3%Am-MOX

1.0

2.0

3.0

4.0

5.0

6.0

0% 2% 4% 6% 8% 10% 12% 14%Th

erm

al c

ondu

ctiv

ity (W

/m/K

)Np content （％）

1073

1273

1473

1.0

2.0

3.0

4.0

5.0

6.0

0% 1% 2% 3% 4%Am content （％）

Ther

mal

con

duct

ivity

(W/m

/K)

TC/1073KTC/1273KTC/1473KTC/1673K

KK

K

O/M=2.00

Effect of MA content

The addition of MA caused to decrease slightly the thermal conductivities in the temperature range of less than 1000K.



The thermal conductivities decrease significantly with decreasing O/M ratio.The equation was derived as functions of temperatures, MA contents and O/M ratios.

It is expected that the equation will be revised by expanding data in the high temperature region.

0.0

1.0

2.0

3.0

4.0

5.0

800 1200 1600 2000 2400Temperature (K)

Ther

mal

con

duct

ivity

(W/m

/K)

O/M=2.00 O/M=1.944 O/M=1.919

O/M=1.945 O/M=1.923

Effect of O/M ratio

( ) ( ) 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



The physical properties, lattice parameters,phase diagram, oxygen potentials, meltingtemperatures and thermal conductivities, ofAm and Np-bearing MOX were measured.The effects of MA addition on the physicalproperties are small. No MA addition affectsfuel properties significantly.We obtained the basic data for conducting theirradiation tests of MA-bearing MOX fuel.

Summary


The expected phase diagram in U-Pu-O ternary system The effect of O/M ratio


2800

2900

3000

3100

3200

1.7 1.8 1.9 2 2.1

UO211.8%Pu20%Pu39%Pu46%PuPuO2-X

Tem

pera

ture

(K)

O/M

Solidus calculated in this work

11.8%Pu

20%Pu

39%Pu

46%Pu

UO

2±X L

3000K

2500K

2000K

Pu0.2 U

0.8 O2 ±X

Pu0.1 U

0.9 O2±X

O/M＝2.0

O/M＝1.5

Limit of hypo-stoichiometric composition

Maximum melting temperature

Limit of hyper-stoichiometric composition

L30

00K

2500

K

2000

K

PuO 2-

x

Pu0.4 U

0.6 O2±X

PuO1.7-UO2

Effect of O/M ratio


0 0.1 0.2 0.3 0.4 0.5 0.6

AmO 2

PuO2

0.1

0.2

0.3

0.4

0.5

at 2980K

0

UO2

Liquid

Solid

0.6

Solid+

Liquid

Database and Models

Modeling


Lattice parameter

Oxygen potential

Melting temperature

1.85 1.9 1.95 2 2.05 2.110-25

10-20

10-15

10-10

10-5

1373 K1473 K1573 K1623 K1623 K1373 K1473 K1573 K1623 K

O/M

PO

2 (atm

)

Markin and McIver[21]Kato et al.[19]

Chilton and Edwards[23]Calculation

Experimental Evaluation of Am and Np Bearing Mixed Oxide ... · 05 10 15 MA Content (%) 29%Pu...

Documents

Transcript of Experimental Evaluation of Am and Np Bearing Mixed Oxide ... · 05 10 15 MA Content (%) 29%Pu...