Equipex PLANEX Orléans

Experimental Planet: In-situ analyses and simulations under extreme conditions
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Context

PLANEX is already the main HP/HT instrumental platform at the regional scale, since it gathers the main actors in this field in Orléans (ISTO, CEMHTI, LPC2E, GREMI), who use and develop equipments in the general field of instrumentation under extreme conditions. In addition to the Labex VOLTAIRE, PLANEX is complemented by its close relationships with ICARE lab, which coordinates the Labex CAPRYSSES, dedicated to the study of combustion and kinetic processes in industrial fluids, using a range of laboratory and modelling approaches. It was the recognition of the common interests between those laboratories that fostered the Orléans group to launch the PLANEX initiative in response to the PIA calls. The P-T range of conditions accessible with the various instruments deployed extends from below atmospheric pressure up to 5 GPa, with a focus in the intermediate pressure range (0.01-0.5 GPa). In terms of temperature, most of our devices go up to 2000°C, with routine access to the 500-1200°C temperature interval. Compared to existing HP-HT platforms in France, that of Orléans is therefore dedicated to intermediate pressures: in particular, we do not use multi-anvil cells to explore high to ultra high pressure conditions, which is the domain of expertise of the LMV at Clermont Ferrand, or diamond anvil cells which are implemented at either IMCMP at Paris or ENS-Lyon, or at other well established European labs in Earth Sciences (e.g., Bayreuth, ETH-Zurich, Bristol).

The development in the high pressure domain has focused on (1) the improvements of instruments allowing the accurate determination of rheological properties of partially molten systems in the pressure range 0.1-5 GPa (Paterson and Griggs apparatuses), and (2) the upgrade of transparent IHPV attached to various spectrometers, both type of instruments being unique in Europe, and possibly in the world, in particular when considered in combination : in both cases the common keyword is insitu. Other research centers in Earth Sciences in Europe have developed an expertise similar to ours in the implementation of IHPV (ex Hannover) allowing accurate control of redox conditions in addition to P-T parameters but none has so far implemented such vessels with a range of spectroscopies (IR, Raman, X-Ray) such as achieved within the framework of PLANEX. As far as we know, such a range of facilities is currently not provided by any other laboratory and we believe that the PLANEX integrated platform stands relatively unique in Earth and Material sciences.

The integration of I. Néel was motivated by various reasons, in particular their skills on transparent vessels, and a common scientific interest on the in-situ determination of properties of hydrothermal fluids. A further reason was to develop an instrument (ie IHPV) common to both lab-sized activities and a large scale instrument such as a synchrotron: the end goal is to offer the academic and industrial communities the possibility of a test phase on an intermediate-sized platform before going to an ESFR-like instrument, whose access is necessarily more limited, and on which single runs of long duration (exceeding 1 week) are hardly achievable, if at all. The last point is particularly important, since a variety of low temperature fluid-rock interaction processes is affected by kinetics, whose role can only be properly accessed via long run durations.

Once operationnal, PLANEX will be part also of the newly launched RéGEF french national network (RÉseau Géochimique et Expérimental Français) integrating all analytical and experimental instruments operated in Earth Sciences laboratories (with an estimated bulk cost exceeding 120 millions euros, and a yearly cost of operation of 10 millions euros). This is a recent initiative coordinated by the Solid Earth Sciences division of CNRS (INSU-TS) which aims at structuring all instrumental facilities in this field so as to facilitate access and optimise the use of the various, mostly intermediate (<500 ke, apart from SIMS, FAME line at ESFR etc..), equipments afforded by the 25 or so Earth Sciences French labs working in the field of Solid Earth. The RéGEF network will be coordinated via a national committee, formed by representatives of the main players, in which ISTO is present. The foreseen evolution of RéGEF is to transform it into a national research infrastructure, similar to the seismic and geodetic RESIF network.

At the European scale, the main part of the experimental facilities hosted by ISTO has been identified as part of the EPOS network (Earth Plate Observing System), whose phase of implementation will end in 2019. This European infrastructure consists of various workpackages, including one focused on laboratory and experimental facilities, in which the ISTO equipments have been listed as accessible, in particular via the response to H2020 calls related to EPOS (ex : trans-national access via INFRAI calls). Although so far EPOS activities have been mostly centered on geophysics, its foreseen development should include geochemical aspects as well and PLANEX will offer a unique set of facilities in this domain.

Impact of Equipex and its role on the site policy

The PLANEX project has had a strong and enduring impact on the structuration of the Orléans campus, via in particular the fostering of many collaborative actions between the partners present in Orléans (ISTO, CEMHTI, LPC2E, GREMI and BRGM). This is manifested by the start of common PhD theses (mostly ISTOCEMHTI and ISTOBRGM), the co-participation to scientific projects in response to regional (région Centre), national (ANR, CNRS) or european (ERC) calls. PLANEX has also tight connections with the labex VOLTAIRE, which provides part of the human ressources used to run/develop some of the equipments of PLANEX. The success of PLANEX has reinforced the strength of the doctoral school (EMSTU) to which the Orléans labs belong, and has helped to develop a common vision for future actions. In particular PLANEX has been pivotal in the setting up of CET-au-centre project, whose major actions have been funded by the région Centre.

One of the main achievement is the acquisition of a new TEM on the Orléans campus (3.5 millions euros, to be delivered in 2018), which will be used by the users of the platform for an in-depth chemical characterisation of quenched run-products. The PLANEX project has been also instrumental in the fostering of the collaboration between the french geological survey (BRGM) and the other academic Orléans labs involved in the project : more specifically, it is clearly seen as a strong opportunity for carrying out experimental simulations of processes, either natural or industrial, involving fluid flow or storage underground, which are themes on which the BRGM actively works, in particular using numerical approaches or via the instrumentation of natural sites : in other words, the PLANEX instruments offer a much needed experimental counterpart to the modelling approaches developped by the BRGM.

On a broader scale, the various facilities developed by PLANEX were also planed to serve as the instrumental backbone of the GEODENERGIES project, a former IEED structure, now transformed into a GIS (Groupement d’Intérêt Scientifique), hosted by BRGM, whose role is to enhance collaborative projects between industria and academia in three main fields : geothermal energy, CO2 capture and storage, and energy storage (ie H2 or compressed air) in geological formations. Altogether, PLANEX can be viewed as an instrumental platform which will serve all actors, either academic or industrial, located on the Orléans campus and outside it, and working in the general field of fluid flow/storage and associated ressources.