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The materials used for the design of solar receivers are one of the critical parts of the concentrated solar power (CSP) plants. An increase in the working temperature of a solar receiver could induce an increase in the efficiency of the CSP plants. Historically, stainless steels were used for solar receivers. However, one limit of these materials is their poor creep resistance at high temperature. Nowadays, Ni-based alloys are used, but they are limited at 1400 K by their oxidation resistance. Thus, to reach higher temperatures, other materials have to be used. Alumina-scale formers, such as FeCrAlloy, possess a very good oxidation resistance at high temperature. The Kanthal Super ER also shows an excellent oxidation resistance. Consequently, FeCrAlloy and Kanthal Super ER were oxidized at 1373 K in air up to 48 h and compared to the currently used nickel-based alloy Inconel 625. Inconel 625 shows an important mass gain followed by the spallation of its oxide scale. On the contrary, FeCrAlloy and Kanthal Super ER have a low mass gain (less than 0.40 mg cm−2) with an adherent oxide layer up to 48 h. Besides the oxidation resistance, the materials have to possess a high solar absorptivity and a total emissivity as low as possible. Oxidized Inconel 625 shows both high solar absorptivity and total emissivity. The other mentioned materials are more suitable due to their high solar absorptivity (> 0.70 for oxidized FeCrAlloy, > 0.80 for oxidized Kanthal Super ER) and their relatively low total emissivity (< 0.35 for oxidized FeCrAlloy, < 0.45 for oxidized Kanthal Super ER). Due to its high oxidation resistance and high solar absorptivity, the Kanthal Super ER seems to be the best candidate for the solar receiver application. [ABSTRACT FROM AUTHOR]

Abstract: An experimental study of the physico-chemical behavior of tungsten under severe conditions is presented. High temperatures (1300⩽ T ⩽2500K) generated by concentrated solar energy, high vacuum (∼10−6 hPa) and proton flux (1keV, ∼1017 ionsm−2 s−1) have been applied on polycrystalline W samples to simulate expected and also unexpected high heat loads that can occur on the ITER divertor (nominal and accidental conditions). During experiment, in situ measurements are performed and the material degradation, the mass loss kinetics, the characterization of the different species coming from the materials under coupled proton flux and high temperatures and the optical properties (reflectivity) are followed. Material characterization using SEM and XRD was investigated before and after treatment to understand the observed behavior. Bidirectional reflectivity measurements were carried out on the tested samples to explain the surface modifications, between the reference sample, the heated sample and the heated and ion irradiated one that can act on the thermo-radiative properties of tungsten. [Copyright &y& Elsevier]

In this paper, the concentrated solar energy is used as a source of high temperatures to study the physical and chemical behaviors and intrinsic properties of refractory materials. The atmospheres surrounding the materials have to be simulated in experimental reactors to characterize the materials in real environments. Several application fields are concerned such as the aerospace and the energy fields: examples of results will be given for the heat shield of the Solar Probe Plus mission (NASA) for the SiC/SiC material that can be used as cladding materials for next nuclear reactor (gas-cooled fast reactor—GFR, Generation IV) and for new advanced materials for solar absorbers in concentration solar power (CSP) plant. Two different facilities—REHPTS and MEDIASE—implemented at the focus of two different solar furnaces of the PROMES-CNRS laboratory—5 kW and 1 MW—are presented together with some experimental results on the behavior of high temperature materials. [ABSTRACT FROM AUTHOR]