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Elemental interdiffusion in W-Ta composites developed for fusion applications

Tungsten (W) was select for an extensive use in nuclear fusion devices due to its low neutron activation, high melting point and sputtering threshold as well as low hydrogen inventory. Nevertheless, W is brittle at low and moderate temperatures, which results in abnormal thermal stress, component fracture and extra erosion under reactor operation due to inherent thermal cycling events. An attractive way to solv...

Blistering of W–Ta composites at different irradiation energies

Pure tungsten and tantalum plates and tungsten–tantalum composites produced via mechanical alloying and spark plasma sintering were bombarded with He+ and D+ energetic ion beams and deuterium plasmas. The aim of this experiment is to study the effects caused by individual helium and deuterium exposures and to evidence that the modifications induced in the composites at different irradiation energies could be fo...

Synergistic helium and deuterium blistering in tungsten–tantalum composites

Tungsten–tantalum composites with 10 and 20 at.% Ta were prepared by ball milling W powder with Ta fibers and by consolidating the milled materials with spark plasma sintering. The composites were implanted at room temperature with He+ (30 keV with a fluence 5 1021 at/m2) and/or D+ (15 keV with a fluence 5 x 1021 at/m2) ion beams. The materials were studied by scanning and high-resolution transmission electron ...

Effects of helium and deuterium irradiation on SPS sintered W–Ta composites at ...

Energetic He+ and D+ ions were implanted into different W–Ta composites in order to investigate their stability under helium and deuterium irradiation. The results were compared with morphological and chemical modifications arising from exposure of pure W and Ta. Special attention was given to tantalum hydride (Ta2H)formation due to its implications for tritium inventory. Three W–Ta composites with 10 and 20 at...

A decision support system for a multi stakeholder's decision process in a portu...

Aim of study: In this paper, we present a decision support system (DSS) to support decision making where different stakeholders have to generate landscape and forest level strategic plans. We further present an interactive approach that may take advantage of a posteriori preference modelling (i.e. Pareto frontier technique) to facilitate the specification of the levels of achievement of various objectives. Area...

Microstructural characterization of the ODS Eurofer 97 EU-batch

Four as-processed forms (Plate 16, Plate 6, Rod 20 and Rod 12.5) of the ODS Eurofer 97 EU-batch produced under different thermomechanical conditions have been investigated by scanning nuclear microprobe, scanning and transmission electron microscopy, energy dispersive X-ray spectroscopy, electron backscattered diffraction, hightemperature X-ray diffraction and microhardness measurements. The materials presented...

Tungsten microstructural changes induced by ISTTOK plasma discharges

Lead concentration and allocation in vegetable crops grown in a soil contaminat...

Lead (Pb) is a very stable metal in soil and is highly toxic to humans and animals. Exposure to Pb occurs via inhalation of particles from industry and soil, as well as household dust, water, and contaminated food. A greenhouse experiment was carried out to evaluate Pb contents and allocation in vegetable crops grown in a soil contaminated by battery recycling wastes. Eight plant species were studied: tomato, s...

Potencialidades hídricas superficiais de Fernando de Noronha, PE, e alternativa...

A disponibilidade de recursos hídricos para usos múltiplos, com ênfase no abastecimento público, é questão da mais alta relevância e depende de aspectos edáficos, hidrológicos, ambientais e de gestão. Avaliou-se o potencial hídrico de bacias hidrográficas da Ilha de Fernando de Noronha, com vistas a dar suporte à gestão da água no arquipélago; para isto se delimitaram e caracterizaram cinco bacias representativ...

Microstructure characterization of ODS-RAFM steels

Results of the microstructural characterization of four different RAFM ODS Eurofer 97 batches are presented and discussed. Analyses and observations were performed by nuclear microprobe and scanning and transmission electron microscopy. X-ray elemental distribution maps obtained with proton beam scans showed homogeneous composition within the proton beam spatial resolution and, in particular, pointed to a unifo...