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International audience; In order to improve the safety of nuclear power plant, loss-of-coolant accident experiments areimplemented in research reactor. In this framework, we develop an optical pyrometry device to measuresurface temperature (700-1200°C) of Zircaloy cladding without contact. The whole set-up of thesimplified device (under air, without radiation) and the measurement procedure including data treatmentbased on bichromatic pyrometry are presented, as well as results for various temperature levels.Temperature retrieval based on the hypothesis of emissivity ratio equal to a constant, is scanned over alarge wavelength range. A constant surface temperature is obtained on the spectral range ofmeasurement, confirming the relevancy of emissivity hypothesis. Differences between this non-contacttemperature measurement and a complementary thermocouple temperature measurement are alsodiscussed.

International audience; The Jules Horowitz Reactor (JHR) is a high performance Material Testing Reactor under construction in southern France (CEA/Cadarache research centre), that will carry out experimental irradiations for Nuclear Power Plants (NPP) and fuel vendors, utilities, safety organizations and research institutes. Therefore CEA is developing a set of test devices that will be operational for the start-up of the reactor or few years later. These experimental hosting systems will have to fulfil experimental needs concerning current NPP technologies (GEN II-III) and future reactors (GEN IV) as well. Experimental programs could be related to either fuel basis properties acquisition, mastering of margins or improvement of fuel products (clad and pellet), in term of performance, safety, maximum burn up, innovative materials or extension of validation domain of fuel performance codes.Then the present paper describes the main experimental hosting systems currently under design The MADISON device will be available at the JHR start up, and will allow testing the comparative behaviour of several instrumented fuel rods (from 1 up to 8 rods, of up to 60 cm fissile stack height) under NPP normal operating conditions (no clad failure expected). The ADELINE device will be available for the JHR start up, and will allow testing a single experimental rod up to its operating limits. The fuel rod will be tested under conditions that correspond to off-normal situations with possible occurrence of a clad failure. The first version so called ADELINE power ramps will focus on the clad failure occurrence during one of these abnormal situations.The LORELEI device will be available few years after the reactor start up and will allow testing a single rod under accidental situation that may lead to fuel damage. It will be able to reproduce all sequences of a LOCA-type transient, including the re-irradiation, the loss of coolant and the quenching phases, on a separate effect approach.In-core and in reflector material test devices are presented as well, corresponding to large ranges of irradiation conditions, in terms of temperature, neutron flux and neutron spectra. A special attention focuses on the improvement of the thermal stability and gradients in the interest zones of irradiated samples. Some specific devices are described such as equipments designed to the qualification of reactor pressure vessel steels (OCCITANE test device), to the studies of creep-swelling of structural materials (MICA test device) or to the study of the stress corrosion cracking assisted by irradiation phenomena (CLOE test device a corrosion loop with an accurate water chemistry monitoring for PWR or BWR requirement).

International audience; One of the main experimental equipment under construction within the Jules Horowitz Reactor isthe LORELEI (Light water One Rod Equipment for LOCA Experimental Investigation). The aim ofthis test device is to study the thermomechanical behavior of the cladding and the fuel rod in order todetermine the radiological consequences in the case of a Large Break LOCA (Loss-Of-Coolant Accident)accident. In order to design appropriately this device it is important to simulate its behaviorin normal operation or in incidental and accidental situations by using a thermal-hydraulic two-phaseflow software. In this paper, we present two different numerical tests corresponding to the two mainworking conditions of the LORELEI device. The first test simulates the working condition of there-irradiation phase, when the device is filled with water and the fuel rod cooled in a natural convectionloop. This test is thought to provide temperature profiles and velocities in the thermosiphoncomponent, both in single and two phase regime, and to determine the power threshold needed tolimits the thermosiphon working conditions. The second test, consecutive to the re-irradiation phase,reproduces the LOCA sequence with the device in a gas environment (steam, helium and hydrogen).For this case, where high temperatures occur, a new dedicated radiative heat transfer module isintroduced. The objective of the simulation is to obtain representative thermal maps of all significativecomponents from the beginning of the LOCA sequence up to the high temperature plateau. Weperform CATHARE-2 computations and compare the results with CFD corresponding simulations.

International audience; Experiments on nuclear fuels and materials in MTRs are a mandatory step for supporting their characterization and qualification before introduction at industrial scale in power reactors. They are the most often carried out in irradiation loops and capsules embarking a lot of instrumentation, either on-line or by integration. Besides measurement of local irradiation conditions (fast and thermal neutron flux, coolant temperature and pressure, stress applied to experimental load etc.), behavior of sample is monitored thanks to specific sensors measuring on-line important parameters for models and codes. However it presents a lot of constraints such as miniaturization, robustness, adapted measurement range with requested accuracy, negligible drift, materials compatibility etc. which can cause technical issues for long duration experiments. Some of these issues can be overcome by equipping with lines either the sample (internal free volume…) or the surrounding connected volumes (coolant pipe, gas gap…). Their role is to collect and route the fluids to specific out-of-pile measurement means which monitor by on-line and delayed techniques specific chemical elements and isotopes released by the sample: fission products, fissile material, activation or corrosion isotopes or molecules, either in normal conditions (high demanding conditions, power transients, innovative coolant chemistry, first barrier loss…) or during safety tests with sample damage (loss of coolant, power injection…). This paper presents the interest of such measurements for supporting the development process of nuclear fuels and materials. Relevant design data for implementation on experimental samples are given. Analysis equipment recommended to be installed in the Fission Product Laboratory and the Chemistry Laboratory of the Jules Horowitz MTR, for activity and for atoms counting, are presented. Such laboratories are underlined as a key service offered by a modern multipurpose irradiation infrastructure.

International audience; For the operational starting of the Jules Horowitz material testing reactor (JHR) in France, CEA intends to promote different experimental devices aiming at testing materials and fuels under irradiation. More specifically, in the safety studies domain, the LORELEI "Light water One Rod Equipment for LOCA Experimental Investigations" test device is dedicated to the study of the thermal-mechanical behavior of a fuel rod and quantification of Fission Product (FP) and fissile material releases under Loss Of Coolant Accident (LOCA) type conditions. Lorelei will allow investigating ballooning and burst of the fuel cladding, clad corrosion phenomena (oxidation and hydriding), post quench behavior and FP release (for that aim, the device will be connected to water and gas sampling lines to the Fission Product Laboratory of the JHR). This paper presents the scientific objectives of the Lorelei device, its main technical characteristics, its experimental protocol and the main options of the preliminary design, based on thermal-hydraulic and mechanical studies. Examinations planned on non-destructive underwater benches and characterization laboratories of the JHR will be detailed, in order to highlight their essential support for gaining as soon as possible exclusive and valuable scientific data on the "as tested" sample.

International audience; The Jules Horowitz Reactor (JHR) is a high performance Material Testing Reactor (MTR) under construction in southern France (CEA Cadarache). JHR will host a set of fuel and material test facilities for the nuclear industry or other organizations. In the safety studies domain, the LORELEI (Light water One Rod Equipment for LOCA Experimental Investigations) test device is dedicated to the study of the thermal-mechanical behavior of a fuel rod and quantification of Fission Product (FP) and fissile material releases under Loss Of Coolant Accident (LOCA) type conditions. LORELEI will allow investigating ballooning and burst of the fuel cladding, clad corrosion phenomena (oxidation and hydriding), post quench behavior and FP release (for that aim, the device will be connected with water and gas sampling lines to the Fission Product Laboratory of the JHR). After a quick description of the JHR, this paper presents the main objectives of the LORELEI test device, its main technical characteristics and its experimental protocol.

International audience

International audience

International audience

International audience; The effects of interfacial adhesion strength on the mechanical behavior of composites of polyamide 66 and precipitated calcium carbonate (CaCO 3) particles have been investigated. The 50 nm average diameter particles have been surface-treated using two kinds of coupling agent having various affinities with respect to the matrix. The surface-modified particles have been incorporated into the polyamide matrix via melt processing. Tensile and impact tests, associated with dynamical mechanical analysis, have been performed on injection-molded samples. The structural characterization of the specimens has been carried out using differential scanning calorimetry and wide-angle X-ray scat-tering. It is observed that the matrix structure is roughly insensitive to the surface treatment, despite a weak nucleating effect of the filler particles. In contrast, the particle sur-face treatment strongly influences the particle dispersion in the polymer matrix. Although dispersion was not optimized, the elastic properties of the reinforced polyamide increase with the CaCO3 content, below as well as above the glass transition temperature. Impact toughness decreases for CaCO3 weight fraction greater than 5%. Scanning electron microscopy investigation reveals that the interfacial adhesion affects local deformation processes, such as debonding and fibrillation of the polymer matrix around the particles. during the macroscopic deformation of the composites