Degradation of Solar Array Components in a Combined UV/VUV High Temperature Test Environment

BepiColombo is the joint mission of the European Space Agency (ESA) and the Japanese Aerospace Exploration Agency (JAXA) to explore the planet mercury. The European contributions, namely the mercury transfer module (MTM) and the mercury planetary orbiter (MPO), are both powered by deployable solar arrays. Many materials and technologies are at their limit under the harsh high-intensity, high-temperature (HIHT) conditions of the mission. Synergistic effects like photo fixation and photo enhanced contamination by ultra violet and vacuum ultra violet radiation (UV/VUV) on sunlit surfaces are considered to play an important role in the HIHT environment of the BepiColombo mission. A design verification test under UV/VUV conditions of sun exposed materials and technologies on component level is presented which forms part of the overall verification and qualification of the solar array design of the MTM and MPO. The test concentrates on the self-contamination aspects and the resulting performance losses of the solar array under high intensity and elevated temperature environment representative for the photovoltaic assembly (PVA)

Degradation of Solar Array Components in a Combined UV/VUV High Temperature Test Environment

BepiColombo is the joint mission of the European Space Agency (ESA) and the Japanese Aerospace Exploration Agency (JAXA) to explore the planet mercury. The European contributions, namely the mercury transfer module (MTM) and the mercury planetary orbiter (MPO), are both powered by deployable solar arrays. Many materials and technologies are at their limit under the harsh high-intensity, high-temperature (HIHT) conditions of the mission. Synergistic effects like photo fixation and photo enhanced contamination by ultra violet and vacuum ultra violet radiation (UV/VUV) on sunlit surfaces are considered to play an important role in the HIHT environment of the BepiColombo mission. A design verification test under UV/VUV conditions of sun exposed materials and technologies on component level is presented which forms part of the overall verification and qualification of the solar array design of the MTM and MPO. The test concentrates on the self-contamination aspects and the resulting performance losses of the solar array under high intensity and elevated temperature environment representative for the photovoltaic assembly (PVA)

Pre-qualification of cladding materials for SCWR fuel qualification testing facility

In frame of the project “HPLWR – Phase 2” (Sept. 2006 to Feb. 2010), prospective cladding materials have been tested up to 650°C and stainless steels, such as 1.4970 which had already been used successfully in sodium cooled fast reactors, turned out to be among the most promising candidates. The main target of the follow-up FP7 project “Fuel Qualification test for SCWR” is to make significant progress towards the design, analysis and licensing of a fuel assembly cooled with supercritical water in a research reactor. The program of dedicated WP4-pre-qualification was focused on evaluation of general corrosion resistance of three austenitic stainless steels 08Cr18Ni10Ti (equivalent of 321), 347H and 316L, which should be pre-qualified for application as a cladding material for fuel qualification tests in SCW conditions. Therefore, the experiments in support of WP4 concentrated on 2000 h corrosion exposures in 25 MPa SCW at two different temperatures 550 and 500oC dosed with 2000 ppb of dissolved oxygen. Coupons manufactured according to ASTM G1-03 with milled surface finish were exposed for 600, 1400 and 2000 h in JRC IET autoclave connected to recirculation loop allowing continual water chemistry control during the test. Following examination of the exposed specimens consisted of weight change calculations and detailed macro and microscopic investigation of oxide layers using SEM, EDX. Furthermore, linear extrapolation to one year of operation in SCW was performed as the most conservative approach. With respect to general corrosion results, all tested steels showed sufficient corrosion resistance in SCW conditions taking into account the conditions foreseen for future fuel qualification test in the research reactor in Rez. When comparing the results of weight change calculations obtained for all three materials, it was found out, that the corrosion resistance increased in the following order: 316L<347 H<08Cr18Ni10Ti.JRC.F.4-Nuclear Reactor Integrity Assessment and Knowledge Managemen

Stress Corrosion Cracking Testing in SCW - Results of SSRT Tests

The presented paper summarizes the results of stress corrosion cracking (SCC) susceptibility tests in supercritical water (SCW), studied for austenitic alloys 316L, 316NG, 347HP and Alloy 690 with the aim to identify maximum SCW temperature usability and specific failure mechanisms prevailing during slow strain-rate tensile (SSRT) tests in ultra-pure demineralized SCW solution with controlled oxygen content. Besides the strain rate (resp. crosshead speed), the oxygen content was varied in the series of tests in case of austenitic stainless steel 316L. The fractography confirmed that failure was due to a combination of transgranular SCC and transgranular ductile fracture. Based on fractographic findings a phenomenological map describing the SCC regime of SSRT test parameters could be proposed for AISI 316L.JRC.DDG.F.4-Safety of future nuclear reactor

High Cr ODS steels performance under supercritical water environment

tThis paper summarizes the results of supercritical water corrosion studies of two ferritic oxide disper-sion strengthen (ODS) steels MA956 and PM2000 at the temperature of the upper limit of potential peakcladding temperature under normal operation, according to the conceptual design being developed inthe EU. As the high temperature and pressure above the thermodynamic critical point of water resultin higher oxidation rate for conventional austenitic alloys than observed in sub-critical light water reac-tor (LWR) conditions, ensuring adequate corrosion resistance is critical for thin-wall components likefuel cladding. This study concentrated on the investigation of two effects, surface finish and orientationof the cuts. Two different surface treated coupons were prepared in order to study the effect of coldwork in sample surface on corrosion resistance. Samples were exposed in supercritical water at 650◦Cand 25 MPa, for up to 1800 h. The corrosion rate was evaluated by measuring the weight change of thesamples and by cross-section examinations. The microstructure of the oxide layers was analyzed using ascanning electron microscope (SEM) in conjunction with energy dispersive spectroscopy (EDS) and X-raydiffraction analysis (XRD). Weight gain results of both ODS steels proved a good resistance to general cor-rosion. Nevertheless the cross-sectional SEM study showed signs of nodular corrosion, observed mostlyon the ground specimens after long exposure times.JRC.F.4-Nuclear Reactor Integrity Assessment and Knowledge Managemen

SCW Facilities Installed in JRC Petten - Past, Present and Future

Currently there are three SCW loops installed and operated in JRC IE Petten for different kind of tests such as SSRT (Slow Strain Rate Tests), Crack Growth Rate and CER (Contact Electric Resistance). In summer 2010, a new SCW loop built by Cormet was installed in JRC IE Petten. The main difference to first generation of SCW loops manufactured by Cormet consists in new two phase het exchanger and pre-heater system which allows reaching up to 20 l/h water flow even at the maximum parameters. First tests were focused on evaluation of the chemistry control at the maximum reachable parameters loop can achieve especially how effectively the oxygen dosed into the system can be controlled. Conclusions comparing the same conditions of the tests by using first generation of SCW loops and the new one are presented. By-pass system installed in high pressure part of the loop allows attachment of different loading devices based on pneumatic bellows technology. The first built prototype, which was developed during common JRC&VTT exploratory research project ¿Miniature Size Autoclave Bellows', is described in this paper.JRC.DDG.F.4-Safety of future nuclear reactor

European Project “Supercritical Water Reactor – Fuel Qualification Test”: Summary of general corrosion tests

The main target of the EUROATOM FP7 project “Fuel Qualification test for SCWR” is to make significant progress towards the design, analysis and licensing of a fuel assembly cooled with supercritical water in a research reactor. The program of dedicated WP4 - Pre-qualification was focused on evaluation of general corrosion resistance of three pre-selected austenitic stainless steels 08Cr18Ni10Ti, AISI 347H and AISI 316L, which should be pre-qualified for application as a cladding material for fuel qualification tests in supercritical water. Therefore, the experiments in support of WP4 concentrated on 2000 h corrosion exposures in 25 MPa SCW at two different temperatures 550 and 500oC dosed with both 150 and 2000 ppb of dissolved oxygen content. Moreover, water chemistry effect was investigated by conducting tests in 550oC SCW with 1.5 ppm of dissolved hydrogen content. At first, corrosion coupons were exposed for 600, 1400 and 2000 h in JRC IET, VTT and SJTU autoclaves connected to recirculation loop allowing continual water chemistry control during the test. Following examination of the exposed specimens consisted of weight change calculations and detailed macro and microscopic investigation of oxide layers using SEM and EDX. With respect to general corrosion results, all tested steels showed sufficient corrosion resistance in SCW conditions taking into account the conditions foreseen for future fuel qualification test in the research reactor in CVR Rez. When the results of weight change calculations were compared for all three materials, it was found out, that the corrosion resistance increased in the following order: 316L<347H<08Cr18Ni10Ti. Results obtained in hydrogen water chemistry did not indicate any significant beneficial effect compared to tests in SCW with 150 or 2000 ppb dissolved oxygen content. Additional tests were dedicated to investigation of surface finish effect. In these exposures polished, sandblasted and plane-milled surface finish technique were investigated. Beneficial effect of surface cold work in particular of sand-blasting was clearly demonstrated.JRC.G.I.4-Nuclear Reactor Safety and Emergency Preparednes

Alirocumab and cardiovascular outcomes after acute coronary syndrome

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