Sylvie Chatain 1 , Jean-Louis Flèche 1 , Mickaël Achour 2 , Laure Martinelli 1
1 Den-Service de la Corrosion et du Comportement des Matériaux dans leur Environnement (SCCME) – CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France 2 Hall de Recherche de Pierrelatte (HRP) – Division Chimie et Enrichissement, F-26701, Pierrelatte, France
Corresponding author: email@example.com Abstract
A thermodynamic description ofthe Fe-Te system modeled via the Calphad method is proposed, based on data published in a preceding publication Part I: Experimental study, and that available in literature. End-member formation energies for the phases , , , and , as well as lattice stabilities of FCC and BCC tellurium, have been evaluated via DFT and used in the numerical optimization. The final Gibbs energy models fit thermodynamicand phase diagram data well, and inconsistencies are discussed. Thethermodynamic description is then used to evaluate Gibbs energy of formation for selected Fe-Te compounds of interest for the modeling of internal corrosion of stainless steel fuel pin cladding during operation of Liquid Metal-cooled Fast Reactors (LMFR).
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Figure 9: Possible in-vessel corium configuration in the case of an in-vessel relocation strategy. a) oxidic melt underneath the metallic melt; b) heavy metal melt formation under the oxidic pool  Since liquid metal has a low emissivity, the radiative heat transfer from the metal is limited. The main part ofthe heat release occurs at the molten metallic layer/steel vessel interface. If the thickness ofthe upper metallic layer is excessively reduced, the so-called focusing effect may take place. In this situation, the heat flux from the liquid metal to the steel vessel is important and it may lead to the vessel breach (if this heat flux is greater than the Critical Heat Flux, CHF=1.5 MWm -2 in the reported scenario). Seiler et al. considered the U-Zr-Fe-O system as a first approximation in-vessel corium. The authors showed that depending on the amount of dissolved iron an inversion ofthe melts density may be observed (Figure 10). The intersection between the oxidic phase density andthe metallic phase density in Figure 10 gives the maximum amount of steel (iron simulates steel behaviour) that stratify under the oxidic pool. For example, for an in-vessel corium with 30 % of oxidised zirconium (C30 in Figure 10), the metallic phase is heavier than the oxidic phase until 25 tons of dissolved iron. This means that a considerable amount of steel may stratify under the oxidic pool. It may be also noted that the density ofthe oxidic phase is practically not affected by theiron addition suggesting that the solubility ofiron in the oxidic phase is limited.
the section at 14 wt pct Si, as indicated by the dotted line in Figure 4 (b). While Balitchev et al. [ 20 ] did not show their calculations for that silicon content, Abou and Malakhov’s [ 22 ] results were similar to those found in the current study, i.e., precipitation of Si at temperatures close to 600 C at 14 wt pct Si. Accordingly, the dotted line in Figure 4 (b) remains unexplained, even by assess- ments based on these experimental results. Along with the conclusions ofthe review presented in Section I, this shows the need for further experiments before rejecting the view proposed long ago and adopted in the present work that no quaternary phase appears in the Al-rich corner ofthe Al-Fe-Mn-Si phase diagram and that the alpha-AlMnSi and beta-AlMnSi phases extend signiﬁ- cantly from the Al-Mn-Si system within the quaternary. The present optimization was ﬁnally used to calculate the section ofthe liquidus projection ofthe Al corner ofthe quaternary Al-Fe-Mn-Si system at 0.3 wt pct Mn for comparison with the experimental section proposed by Munson. [ 6 ] The few data points used by these authors were located along the boundary between the alpha- AlMnSi andthe alpha-s 5 phases, while all other bound-
A technique for the microstructural studyof steels, based on the use of matrix dissolution to collect the very low number density precipitates formed in martensitic steels, has been considerably improved. This technique was applied to two different grades of alloy, characterized by high nickel and cobalt contents and varying chromium, molybdenum and vanadium contents. The technique was implemented at tem- peratures ranging between 900 !C and 1000 !C, in order to accurately determine experimental data including the crystallographic structure and chemical composition ofthe carbides, the carbide solvus temperatures, and variations in the chemical composition ofthe matrix. These experimental investiga- tions reveal that the solubility of molybdenum in FCC carbides can be very high. These results have been compared with the behavior predicted by computational thermodynamics, and used to evaluate and improve thethermodynamic Matcalc steel database. This upgraded database has been validated on three other steels with different chemical compositions, characterized by the same Fe–Cr–Mo–V–C system.
c = 9 . 927
in the two phase domain η + ZrSn 2 . The two alloys in the two
phase domains were selected to studythe η phase at its richest and poorest Zr compositions. To studythe A 15 phase, an alloy with 20 at.% Sn was synthesized. In none ofthe samples, weight losses exceeded ∼ 1%. The annealing was performed under argon in a silica tube. In order to avoid any reaction with the silica the alloys were protected with Ta foils. The sample with the nominal composition 20 at.% Sn was annealed for 240 h at 1273 K. The samples, which contained 34, 41 and 49 at.% Sn, were annealed for 216 h at 1273 K. After the annealing treatment the alloys were quenched in water at room temperature. The sample containing 40 at.% Sn was annealed for 6 h at 1883 K in an induction furnace in a cold copper crucible under argon atmosphere and quenched by turning off the induction power. This annealing treatment was performed in order to check the closure ofthe miscibility gap. DSC experiments were performed on a sample with 10 at.% Sn previously thermally treated at 1073 K during 680 h.
to foresee the O/M of these compounds under different conditions. Thanks to the new experimental data acquired on the U-Am-O system, a CALPHAD assessment will be performed andthe resulting model will be integrated in theThermodynamicof Advanced Fuel International Database (TAFID).
was now examined how well the site fraction y O 2 follows a CaO in
the CaO–Al 2 O 3 –SiO 2 system. Lines for a series of those two
quantities were thus calculated from the present model, and have been plotted in Figs. 16 and 17. There is an encouraging similarity, and it may be interesting to continue this study by examining which of these two actually describes the puriﬁcation power ofthe slag best.
Thermodynamicstudyofiron-fluorinesystem Sylvie Chatain 1 , Mickaël Achour 2 , Jean-Louis Flèche 1 , Laure Martinelli 1
1 Den-Service de la Corrosion et du Comportement des Matériaux dans leur Environnement (SCCME) – CEA, Université Paris-Saclay, F-91919, Gif-sur-Yvette, France 2 Hall de Recherche de Pierrelatte (HRP) – Division Chimie et Enrichissement, F-26701, Pierrelatte, France
the temperature was reduced, andthe carrier gas was inserted with controlled humidity. In this middle part ofthe experiment, P D E F was kept constant, and increasing T plateaus were performed throughout the experiment. The @T, P D E F G conditions were maintained until stabilization ofthe mass signal. We observe an almost instantaneous 8% mass uptake with the insertion of humid gas (the mass ofthe sample increases from 4.20 mg to 4.54 mg). Afterward, we observe that for each increasing T step, the sample loses mass and m d reaches a new equilibrium value. This systematic behavior can be observed in the areas identified as zones 1 and 2, better shown in Figure 3(b) and Figure 3(c), respectively. According to @T, P D E F G, the overall mass m d ofthe sample can increase or decrease by hydration or dehydration processes. This behavior can be identified as bivariant, as the equilibrium values of m d depend on both intensive parameters ofthesystem, T and P D E F (two degrees of freedom).
Table 6 ).
Fluorine studies in Earth Science are far from complete. As concluding remarks, we summarize four challenges discussed above. (1) Behavior of F in hydrosphere: data on F abundance in various surface waters, especially other than ocean, are required for understanding the F transfer be- tween hydrosphere and crustal rocks during erosion and weathering. In addition, the role of biology in surface F cycle needs to be assessed quantitatively. (2) F abundance in metamorphic rocks: amount of F present in various types of metamorphic rocks is not studied extensively so far. Because of this, geochemical transport of F during the metamorphism is yet to be understood, except for certain cases related to a prograde metamorphism during the subduction of an oceanic lithosphere [22c] . (3) F abundance in mantle peridotites: data on F abundances in peridotites are also scarce. This prevents an assessmentof F abundance in the mantle from the peridotite data. Fluorine is also expected to provide an additional geochemical vector characterizing the metasomatic process in the mantle beneath continents, for example, providing insights into the origin of kimberlite (a diamond-bearing magma). (4) F incorporation in metallic core: although F is not expected to incorporate into the metallic more in a large quantity, even a small quantity can in ﬂuence the terrestrial budget signi ﬁcantly. Furthermore, at the extreme high pressure and temperature, new F-bearing minerals can be formed. Investigation of chemical reaction at the extreme condi- tions therefore potentially brings in new discoveries regarding F behavior deep inside the Earth.
boundaries of two-phase samples evaluated from the composition analyses via EDS and WDS. The respective tie-lines are shown in Figure 2, imposed on the calculated phase diagram compared with published phase boundary data (see Part II: Thermodynamic modelling). Filled symbols represent the prepared average sample compositions (Table 2), and empty symbols represent the evaluated phase boundary compositions (Table 3). The tie-lines are overall consistent with available solubility data. Most heat treated samples showed no to small interaction with the silica ampoule. Samples treated in equilibrium with liquid showed a thin, soot-like, dark layer on the inner wall ofthe ampoule; while a reaction had clearly taken place, the extent was deemed small enough to not affect the state ofthe bulk sample andthe ampoules remained intact. The largest extent of reaction was seen in sample FT58_S2, being cratered with large semi-spherical bubbles. The outer rim ofthe sample showed a clear and uniform, about 5 µm thick, region of phase composition. Analysis ofthe deposits on the ampoule revealed tellurium oxide particles. In all two-phase samples, oxygen was concentrated in the most Fe-rich phase, i.e. the phase with more vacant interstitial sites.
Databases for CALPHAD-type calculations have been made available for each ofthe corners ofthe Al–Fe–Ti system. The concerted European COST action 507 has led to the
development of a database for aluminium alloys  for which assessments were however limited to the description of binary and some ternary systems, but not the Al–Fe–Ti one. In fact, no CALPHAD-type description ofthe whole ternary Al–Fe–Ti system is available at present. As a matter of fact, the only tentative CALPHAD-type assessmentofthe Al–Fe–Ti system is due to Dew-Hughes and Kaufman  who calculated the 1000 °C isotherm. The extension of both the Laves phase andthe B2-ordered phase FeTi in the ternary system was unexpected for these authors, who assumed that Al should have substituted Ti in both phases, and this led them to perform new experiments which just confirmed previous data. Their conclusion, which appears still valid, is that further theoretical studies should attack the problem.
Dans ce stade on cherche sue la méthode plus approprier pour les caractéristiques physico-chimiques des eaux d'alimentation et la méthode moins couteux.
 Amini M., Abbaspour K.C., Berg M., Winkel L., Hug S.J., Hoehn E., Yang H., Johnson C.A. Statistical modeling of global geogenic. arsenic contamination in groundwater. Environmental Science and Technology. 2008, 42, 3669 –3675.
lower continental crust, by a factor of 1.4 - 2.3 (Rudnick and Gao 2004).
Fluorine contents in magmatic rocks are in the 100s to 1000s of ppm range. Highly fractionated peraluminous and peralkaline granitoids, and some basaltic rocks, show the highest abundances, as F is generally concentrated into magmas during crystal fractionation. In addition, F is incorporated into silicate melt by bonding to Si and Al, resulting its higher solubility in felsic than mafic melts (Dalou et al. 2015).
+ + 4 ↔ ∙ 4 +
Solid particles must fulfill specific requirements, in particular concerning the size. Thus, the control ofthe crystal growth becomes a key parameter during the uranium peroxide precipitation. Moreover, the solubility product, K s , is required to calculate the driving force on which the kinetic law depends. For the uranium peroxide precipitation, the supersaturation ratio, , is linked to the activities ofthe uranyl and peroxide ion as:
The modeling of CaO-MoO 3 , Na 2 O-MoO 3 , Na 2 MoO 4 -CaMoO 4 andof SiO 2 - Na 2 O-MoO 3 systems has been carried out. This study makes it possible to predict the formation ofthe molybdate phases in the simplified glass melt. The next step will focus on the introduction of B 2 O 3 in the database to get closer to the real industrial glass composition.
Borrelly et al. determined the solubility in the different solid solutions. The phase diagram was reviewed in the whole composition range by Alekseeva et al. . Later, Bhanumurthy et al. [47,48] and Kumar et al.  reported the C16 phase to be a high temperature stable phase. Servant et al.  reinvestigated the invariant reaction temperatures as well as the melting temperature ofthe C15 phase. A detailed review and a very careful reinvestigation ofthe whole composition range of this system has been carried out by Stein et al.  using metallography, XRD, EPMA and DTA measurements. These authors have shown that the presumed Fe 23 Zr 6 compound stable at high temperature is actually an
In addition, during the knee’s ﬂexion—extension, there is automatic rotation ofthe tibia, which authors have agreed has a real inﬂuence on the patellar tracking  , even if this inﬂuence has not been accurately described  . This assessment problem may be related to the probable existence of several instantaneous rotation axes during the ﬂexion—extension cycle  . The studies that controlled for this rotation  show great variability in this aspect of patellofemoral kinematics, which is why a certain number of authors leave the rotation free. We opted for this second solution in our study with a method that allowed us to apply return strength to the tibia at the same time.
The tests conducted on a single spiral followed a factorial design using wash water addition, feed rate and slurry solids concentration as the experimental factors. For the test conditions the wash water addition was found to have the most significant effect on the spiral performance. Increasing the wash water flow rate enhances the concentrate grade but reduces theiron recovery. The major effect of wash water was found to be on coarse particles. Other experimental factors (feed rate and slurry solids concentration ofthe feed) did not show any significant effect on recovery and concentrate grade. This result is most likely due to the high amplitude of wash water variation applied for the tests compared to that of other factors. The application of a stepwise regression confirms the significant effect ofthe wash water addition on theiron recovery and concentrate grade. Subsequent testing for these variables should use lower amplitude of wash water variation in order to be able to identify the effect of slurry solids concentration and feed rate on the spirals performance. In summer 2014 tests were conducted on a test rig consisting of three parallel spirals with 3, 5 and 7 turns at COREM. The test rig is well conceived and operates in a closed circuit with a recirculation of wash water addition, which is automatically controlled. A sampling system allows simultaneous sampling from 24 streams to minimize the disturbance to the process. The main objective ofthe test work on the test rig is to provide an answer to the initially felt obvious question of: ‘What is the effect ofthe number of turns on spirals performance?’ Answering this question will help plant operators to decide whether they should invest in 5-turn or 7-turn-spirals, or even a 3-turn-spiral could be sufficient for their needs. The parallel spirals are operated at identical operating conditions, e.g. feed characteristics (flow rate, slurry solids concentration and composition). Although more than 10 tests were conducted on the spiral test rig, we have not been able to clearly identify the role ofthe number of turns on spirals operation. In most ofthe tests the 3-turn-spiral outperforms, in terms of recovery, the 5 and 7-turn-spirals. There is no explanation to this counter intuitive behavior ofthe spirals and at the time of writing these lines the personnel of COREM is still investigating the process to identify the origin of this behavior (M. Renaud, March 2015, personnel communication).