Experimental Evaluation of Am and Np Bearing Mixed Oxide Fuel - - PowerPoint PPT Presentation

Japan Atomic Energy Agency

Plutonium Fuel Development Facility

Experimental Evaluation

• f 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

• xide containing minor actinides

(MA-MOX) as a fuel of the advanced fast reactor. Specification of the fuel pellet Type : Hollow type Pu content : 20 - 30% MA content : - 5%(Np+Am+Cm) Density : 93%TD O/M ： 1.95 Burn-up : 150GWd/t Hollow pellets of MOX Pellets of (Np0.02Am0.02Pu0.3U0.64)O2

Background

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

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Outline

Sample preparation Phase state and Phase separation Lattice parameters Oxygen potentials Melting temperatures Thermal conductivities

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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

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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 2.00-1.909 2.00-1.924 2.00-1.914 2.00-1.909 2.00-1.951 2.00-1.923 2.00-1.919 2.00-1.971 2.00-1.942 2.00-1.947 2.00 2.00-1.916 2.00-1.961 2.00 2.00 2.00-1.718 2.00 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)

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Homogeneity of samples

100 200 300 400 500 600 700 110 115 120 125 130 135 140 145 2θ I ntensi ty 100 200 300 400 500 600 700 800 900 1000 110 115 120 125 130 135 140 145 ２ θ I ntensi ty

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 20 40 60 80 100

fcc single phase Two pahases

O/M Two phases Pu content (%) Single phase

200 400 600 800 1000 1200 ２ θ I nt ens i t y

100 200 300 400 500 600 110 115 120 125 130 135 140 145 2θ I nt ensi ty

Two fcc Phases Single fcc Phase

Sari et al.

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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 5 10 15 20 MOX 6%Np-MOX 12%Np-MOX 1.8%Np/Am-MOX 2.4%Am-MOX Phase separation temperature (K ) MA content (%) MOX-Np MOX-Np/Am MOX-Am O/M=1.91-1.93

The effect of MA content on the phase separation temperature.

No effect of phase separation

• n the fuel properties.

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Lattice parameters

5.42 5.43 5.44 5.45 5.46 5.47 5 10 15 MA Content (%)

29%Pu 40%Pu

Am/Np-MOX Np-MOX Am-MOX Calculation Am/Np-MOX Np-MOX Am-MOX Experiment Lattice parameter (A)

• 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-MOX 20%Pu-MOX-1 20%Pu-MOX-2 6%Np-MOX 12%Np-MOX MOX-1 1.8%Np/Am-MOX 2%Np/Am-MOX 40%Pu-MOX 46%Pu-MOX 30%Pu-MOX Lattice parameter (A) O/M

Reference [11]

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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(mg) PO2(atm) Time(s) TG PO2

15 min

FM

Gｌ

• ｖ

e Box

Air Damper Oxygen sensor Oxygen sensor 220cc/min Gas Mixer TG-DTA (Rigaku TG812 8120 mo 0 mode del ) Measurement Temperature : ～1400℃ Thermo Gravimetry Horizontal al dif differentia ial l ty type pe ba bala lance Acc Accuracy racy o

• f t

the w e weig eight m mea easu surem ement ent : : ±1μg g (O/M :±0.00015) Sample Reference(Al2O3) 200cc/min MFC MFC He/0.05%H

2

He/5%H

2

He 20cc/min

Instrument adding water vapor

Gas System

1～2000ppmH2O 0.01～5%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

1000 1200 1400 1600 1800 2000 ΔGO2 (kJ/mol) Temperature (K) (U0.8Pu0.2)O1.995 (U0.7Pu0.3)O1.995 (U0.9Pu0.1)O1.995 (U0.6Pu0.4)O1.995 Besmann et al. 10%Pu 40%Pu (U0.66Pu0.3Am0.02Np0.02)O1.995 AmO1.995 (Thiriet and Konings) 20%Pu 30%Pu NpO1.995 (Bartscher and Sari) (U0.65Pu0.3Am0.045)O1.995 (Osaka et al.) (U0.656Pu0.32Am0.024)O1.995

1.96 1.97 1.98 1.99 2.00 2.01

• 500
• 450
• 400
• 350
• 300
• 250

1623K 1573K 1473K 1623K 1573K 1473K H I J O/M ΔGo

2(kJ/mol)

(U,Pu,Np,Am)O2-X (U0.7Pu0.3)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

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2500 2600 2700 2800 2900 3000 100 200 300 400 500

Elapsed time Temperature (°C)

Melting temperatures

2200 2400 2600 2800 3000 3200 3400 2200 2400 2600 2800 3000 3200 3400

Melting point measuered in this work (K) Melting point (K)

Ta Mo Nb Al

2O 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

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2800 2900 3000 3100 3200 10 20 30 40 50

Solidus Re Solidus Solidus Solidus

mol% PuO2 Temperature (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 10 20 30 40 50

Solidus Re Solidus Solidus Solidus

mol% PuO2 Temperature (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 Temperatures UO2- PuO2 system and effect of MA addition

2900 2950 3000 3050 3100 3150 10 20 30 40 50

D Re inner capsule W capsule

Pu content (%) Temperature (K)

Solid Liquid

(a) Am content : 0-3.3% 2 4 6

Np Am Np/Am Np Am Np/Am 38-42%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 supply Thermo couple Glove box

• High temperature furnace

Resistance heating furnace

• Temperature-measuring

device

W-Re thermo couple

• Laser source

Nd glass Laser

Maximum output 17 J / Pulse

• Infrared detector

InSb 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 and Power 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 Thermal conductivity (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.

λ λ × = 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 specimen ρth : Theoretical density of specimen

( ) ( )

p p F × + − = β 1 1

F : Maxwell-Eucken equation β =0.5

Plutonium Fuel Development Facility 1 2 3 4 5 6 800 1000 1200 1400 1600 1800

Temperature (K) Thermal conductivity (W/m/K) 6%Np-MOX 12%Np-MOX 0.7%Am-MOX 2%Am-MOX 3%Am-MOX

1.0 2.0 3.0 4.0 5.0 6.0 0% 2% 4% 6% 8% 10% 12% 14% Thermal conductivity (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 （ ％） Thermal conductivity (W/m/K)

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

K K 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 2400 Temperature (K) Thermal conductivity (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

( ) (

)

T x x

4 2

• 2

2

• 1

1

• 10

493 . 2 2.625

• 10

1.595 z 10 6.317 z 10 3.583 2.713 1

−

× + + × + × × + × × + = λ

⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ × × + T T

4 2 / 5 11

10 522 . 1 exp 10 541 . 1

z1: Am content z2: Np content x:Deviation x in MO2-x

Thermal conductivity

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The physical properties, lattice parameters, phase diagram,

• xygen

potentials, melting temperatures and thermal conductivities, of Am and Np-bearing MOX were measured. The effects of MA addition on the physical properties are small. No MA addition affects fuel properties significantly. We obtained the basic data for conducting the irradiation tests of MA-bearing MOX fuel.

Summary

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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 UO2 11.8%Pu 20%Pu 39%Pu 46%Pu PuO2-X Temperature (K) O/M Solidus calculated in this work 11.8%Pu 20%Pu 39%Pu 46%Pu

UO2±X L 3000K 2500K 2000K Pu

. 2

U

. 8

O

2 ± X

Pu0.1U0.9O2±X O/M＝2.0 O/M＝1.5 Limit of hypo-stoichiometric composition Maximum melting temperature Limit of hyper-stoichiometric composition L 3000K 2500K 2000K PuO2-x

Pu

. 4

U

. 6

O

2 ± X

P u O

1.7

• U

O

2

Effect of O/M ratio

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0.1 0.2 0.3 0.4 0.5 0.6 AmO2 PuO2 0.1 0.2 0.3 0.4 0.5 at 2980K 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 2.1 10-25 10-20 10-15 10-10 10

• 5

1373 K 1473 K 1573 K 1623 K 1623 K 1373 K 1473 K 1573 K 1623 K O/M

P

Markin and McIver[21] Kato et al.[19] Chilton and Edwards[23] Calculation