experimental evaluation of am and np bearing mixed oxide ...experimental evaluation of am and np...
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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
Plutonium Fuel Development Facility
- 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
Plutonium Fuel Development Facility
Outline
Sample preparation
Phase state and Phase separation
Lattice parameters
Oxygen potentials
Melting temperatures
Thermal conductivities
Plutonium Fuel Development Facility
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
Plutonium Fuel Development Facility
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)
Plutonium Fuel Development Facility
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
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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.
Plutonium Fuel Development Facility
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.
Plutonium Fuel Development Facility
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]
Plutonium Fuel Development Facility
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
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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
Plutonium Fuel Development Facility
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
Plutonium Fuel Development Facility
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
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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
Melting Temperatures
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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
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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
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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
Thermal conductivity
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
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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.
Thermal conductivity
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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
Thermal conductivity
Plutonium Fuel Development Facility
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
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Plutonium Fuel Development Facility
The expected phase diagram in U-Pu-O ternary system The effect of O/M ratio
Melting Temperatures
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
Plutonium Fuel Development Facility
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
Thermal conductivity
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