Solidus and liquidus temperatures in the UO2–PuO2 system

Kato, Masato; Morimoto, Kyoichi; Sugata, Hiromasa; Konashi, Kenji; Kashimura, Motoaki; Abe, Tomoyuki

doi:10.1016/j.jnucmat.2007.06.002

Cited by 68 publications

(52 citation statements)

References 20 publications

(41 reference statements)

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“…Given the limited amount and the high radioactivity of the investigated material, this dataset size was considered to be satisfactory, in that it permitted to obtain significant average values and standard deviations for each composition. The laser pulses lead to maximum temperatures between 3350 K and 3550 K. These temperatures compared with the expected values of the solid/liquid phase transitions for the pure dioxides [21][22][23][24][25]27,29], can be considered to be high enough to melt a sufficient amount of material to obtain a consistent thermal analysis during the cooling stage of the experiments.…”

Section: Laser Meltingmentioning

confidence: 94%

“…The method used for the melting experiments is based on laser heating and a self-crucible approach in order to avoid sample-crucible interactions during the measurements. It was recently applied to UO 2 [21], PuO 2 [22,23], U 1Àx Pu x O 2 [24,25] and MA-doped U 1Àx Pu x O 2 samples [26], and proved to give more accurate values than those previously obtained through more traditional thermal analysis methods [24,25,27]. The samples were also characterised after melting using powder X-ray Diffraction (XRD) and X-ray Absorption Spectroscopy (XAS).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Melting behaviour of americium-doped uranium dioxide

Prieur

Lebreton

Caisso

et al. 2016

The Journal of Chemical Thermodynamics

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a b s t r a c t (Uranium + americium) mixed oxides are considered as potential targets for americium transmutation in fast neutron reactors. Their thermophysical properties and notably their melting behaviour have not been assessed properly although required in order to evaluate the safety of these compounds under irradiation. In this study, we measured via laser heating, the melting points under inert atmosphere (Ar) of U 1Àx Am x O 2±d samples with x = 0.10, 0.15, 0.20. The obtained melting/solidification temperatures, measured here, indicate that under the current experimental conditions in the investigated AmO 2 content range, the solidus line of the (UO 2 + AmO 2 ) system follows with very good agreement the ideal solution behaviour. Accordingly, the observed liquidus formation temperature decreases from (3130 ± 20) K for pure UO 2 to (3051 ± 28) K for U 0.8 Am 0.2 O 2±d . The melted and quenched materials have been characterised by combining X-ray diffraction and X-ray absorption spectroscopy.

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Section: Laser Meltingmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Melting behaviour of americium-doped uranium dioxide

Prieur

Lebreton

Caisso

et al. 2016

The Journal of Chemical Thermodynamics

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“…In the hypothetical case of no interaction between the solution end-members, assuming that the heat capacity is approximately the same for solid and liquid phases in the vicinity of melting, and taking into account that the only entropy contributions to Gibbs free energy are related to configurational terms, the idealsolution solidus and liquidus lines of the binary phase diagram are solely defined by the melting temperatures and the enthalpies of fusion of the two end members [28] as shown by the dotted lines in figure 7. Actinide dioxide melting enthalpy values assessed by Konings et al [29] are used to calculate the optimised solidus and liquidus plotted in figure 7 together with the current experimental data.…”

Section: Phase Diagram Considerationsmentioning

confidence: 99%

High temperature phase transition of mixed (PuO 2 + ThO 2 ) investigated by laser melting

Böhler

Cakir

Beneš

et al. 2015

The Journal of Chemical Thermodynamics

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a b s t r a c tA laser heating approach combined with fast pyrometry in a thermal arrest method was used to provide new data for the melting/solidification phase transition in mixed (PuO 2 + ThO 2 ) at high temperature. At low concentration of ThO 2 in PuO 2 a minimum in the solidification temperature in the pseudo binary (PuO 2 + ThO 2 ) was observed. The minimum was found around a composition with 5 mol% ThO 2 . Phase transition temperatures of other compositions are closer to an ideal solution behaviour. To detect changes in the material a complete investigation with electron microscopy, Raman spectroscopy and powder X-ray diffraction was done. Raman vibration modes were found, that are characteristic for materials containing PuO 2 , and high temperature segregation effects during solidification were described. The results obtained in the present work are compared to other mixed actinide dioxides and compared to the ideal solution case for this system. The presented results show the importance of the hightemperature oxygen chemistry in this actinide oxide phase.

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“…Also, some other researchers [11,[14][15][16][17] [19,20] has the advantages of much shorter heating duration and quasicontainerless conditions and avoids most of the typical problems of traditional furnace techniques. Our MD calculated melting temperature, which lies between 2800 K and 2825 K, is lower than the melting point reported by Bruycker et al [20] and higher than the recommended value by ORNL [17] but matches well with the value reported by Kato et al [19].…”

Section: Enthalpy and Density Variation Of Th Rich (Thu)o2 And (Thpmentioning

confidence: 99%

“…ThO2 3650-3675 3663 ± 100 Benz et al [6] 3643 ± 30 Rand et al [7] 3573 ± 100 Lambertson et al [8] 3651 ± 17 Ronchi et al [9] 3624 ± 108 Bohler et al [10] UO2 3050-3075 3113 ± 20 Lyon et al [11] 3138 ± 15 Latta et al [12] 3075 ± 30 Ronchi et al [13] 3120 ± 30 Adamson et al [14] 3,113.15 MATPRO [15] 3138 ± 15 Komatsu et al [16] 3120 ± 30 ORNL [17] 3050 ± 55 Böhler et al [18] PuO2 2800-2825 2663 ± 20 Lyon et al [11] 2701 ± 35 Adamson et al [14] 2647 MATPRO [15] 2718 Komatsu et al [16] 2701 ± 35 ORNL [17] 2843 Kato et al [19] Table 4: MD calculated enthalpy increments (in J/mole) of solid and liquid phases of (Th,U)O2 and (Th,Pu)O2 MOX are fitted to equation (7) and (8), respectively and coefficients are enlisted.…”

Section: Calculated Temperature Range (K) Experimental Values (K)mentioning

confidence: 99%

Melting behavior of (Th,U)O2 and (Th,Pu)O2 mixed oxides

Ghosh

Kuganathan

Galvin

et al. 2016

Journal of Nuclear Materials

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The melting behaviors of pure ThO2, UO2 and PuO2 as well as (Th,U)O2 and (Th,Pu)O2 mixed oxides (MOX) have been studied using molecular dynamics (MD) simulations. The MD calculated melting temperatures (MT) of ThO2, UO2 and PuO2 using two-phase simulations, lie between 3650-3675 K, 3050-3075 K and 2800-2825 K, respectively, which match well with experiments. Variation of enthalpy increments and density with temperature, for solid and liquid phases of ThO2, PuO2 as well as the ThO2 rich part of (Th,U)O2 and (Th,Pu)O2 MOX are also reported. The MD calculated MT of (Th,U)O2 and (Th,Pu)O2 MOX show good agreement with the ideal solidus line in the high thoria section of the phase diagram, and evidence for a minima is identified around 5 atom% of ThO2 in the phase diagram of (Th,Pu)O2 MOX.

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Solidus and liquidus temperatures in the UO2–PuO2 system

Cited by 68 publications

References 20 publications

Melting behaviour of americium-doped uranium dioxide

Melting behaviour of americium-doped uranium dioxide

High temperature phase transition of mixed (PuO 2 + ThO 2 ) investigated by laser melting

Melting behavior of (Th,U)O2 and (Th,Pu)O2 mixed oxides

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