[en] This paper reports on the assessment of a nano-indentation test, using tips of spherical geometry, to calculate the mechanical properties of nuclear materials at the micron-scale. The test method is based on incrementally loading and unloading the tip into a sample of material with unknown mechanical properties. The incremental indentation stress, strain and elastic modulus are calculated by analysing each increment's unload curve. Two samples of iron and tungsten were used with a spherical indenter tip with an apparent radius of 30 μm. The method for calculating the mechanical properties is based on two markers that define the top and bottom of each load increment's unload curve. As such, the bottom marker can be moved down the unload curve to increase the proportion of data included in the results. This simulates increasing the percent unloaded from just one data set. The results showed that increasing the percent unloaded during each increment was beneficial as it reduced the effects of creep at the top of the unload curve and pile-up of material around the indenter tip as the test progressed. However, it is likely that increasing the percentage unloaded results in the inclusion of a higher proportion of reverse plasticity effects in the calculated results. (authors)

[en] In this paper the experimental results of tensile properties and indentation properties, as a function of pyramidal and spherical indenters, of Copper-Chromium-Zirconium alloy, in the macro-scale range at room temperature, are presented and compared. Measurements are performed on three Cu-Cr-Zr samples in order to evaluate different heat treatments: two samples are aged for 2 hours in a vacuum furnace at 480 °C, 550 °C and one sample is kept as received. The experimental procedures for the measurement of indentation modulus, by using the primary hardness standard machine at INRiM, and tensile modulus, by means of engineering tensile tests at CIRA, are described. (paper)

[en] We present the Dual-beam ion irradiation facility for FUsion materials (DiFU) developed at Ruđer Bošković Institute in Zagreb, Croatia. It has a versatile setup which allows irradiation of fusion materials samples by one or two ion beams as well as other similar experiments. Two beamlines come to the DiFU chamber at an angle of 170 between them, from 6 MV HVE Tandem VDG and 1 MV HVE Tandetron accelerator. Ion beam handling and scanning systems enable fast electrostatic scanning of the beams over the sample at kHz frequencies, and irradiation of areas up to 30 x 30 mm². The sample holder enables XYZ positioning of heated, cooled or room temperature samples. Ion fluxes are measured indirectly by insertion of two large Faraday cups in ion beams and the ion flux is also monitored continuously by two sets of XY slits. Conditions during irradiation are monitored by a set of thermocouples, an IR camera, a high-sensitive video-camera, and a residual gas analyser. The DiFU facility has been developed according to ASTM standard E521-16 with support from EUROfusion, the IAEA and the Croatian Science Foundation.

[en] Due to restrictions on both the specimen volumes available and the activity levels research facilities can handle, testing techniques on the micron-scale are very attractive for the study of irradiated material. However, the results of such small tests are convoluted by plasticity size-effects. Spherical nano-indentation is increasingly used to probe irradiated material, but to characterise the area of plastic deformation surrounding indentations a method capable of providing crystallographic information at extremely high spatial resolution is required. Transmission Kikuchi Diffraction (TKD) is a novel diffraction technique that can be performed in a scanning electron microscope. Using this technique, spatial resolutions below 10 nm have been achieved. Initial results, shown here, demonstrate the use of TKD in mapping the lattice rotations caused by indentation produced with a spherical diamond tip. With the addition of strain mapping software the plastic zone size was also evaluated for the first time using diffraction patterns generated via TKD. For a tip of radius 15 μm, inserted into Fe to a strain of 0.07, the plastic zone was observed to extend 1.3 μm to either side of the incident location of indentation and the deformation depth was approximately 0.5 μm. (authors)

[en] Highlights: • Particle beam-component interaction was analysed developing and applying numerical codes. • Gas density distribution was calculated with AVOCADO code and applied for electrical analyses. • High heat flux components were designed, analysed with subcooled boiling, verified for fatigue. • Fracture behaviour of ceramics was analysed by finite element modelling and was verified. • R&D supports the design of the beamline components, especially for water-vacuum barriers. - Abstract: The design of the beamline components of MITICA, the full prototype of the ITER heating neutral beam injectors, is almost finalised and technical specifications for the procurement are under preparation. These components are the gas neutraliser, the electrostatic residual ion dump, and the calorimeter. Electron dump panels are foreseen each side of the upstream end of the neutraliser to protect the cryo-panels from electrons, created by stripping and other processes, that exit the 1 MeV accelerator. As the design of the components must fulfil requirements on the beam physics, insight on physical processes is required to identify performance trade-offs and constraints. The spatial gas distribution was simulated to verify the pumping requirements with electron dump panels and local conditions for breakdown voltage. Electrostatic analyses were carried out for the insulating elements of the RID to verify the limits of the electric field intensity. Different criteria were approached to investigate the fracture behaviour of ceramics considering the manufacturing implications and extrapolating the conditions for proof testing. Severe heating conditions will be applied steadily, as the maximum pulse duration is 1 h, and cyclically so requiring to fulfil fatigue and ratcheting verifications. High heat fluxes, up to 13 MW/m"2 on the calorimeter, with enhanced heat transfer in subcooled boiling conditions will occur in the actively cooled CuCr1Zr panel elements provided with twisted tapes as turbulence promoters. Special R&D activities were undertaken to support the design: manufacturing of thick twisted tapes leading to an increased cooling performance while maintaining flow rate requirements, bending of swirl tubes, verification for permanent deformations due to stress relaxation after heating of swirl tubes, double side deep drilling of 2 m long CuCr1Zr plates.

[en] In fusion reactors, surfaces of plasma facing components (PFCs) are exposed to high heat and particle flux. Tungsten and Copper alloys are primary candidates for plasma facing materials (PFMs) and coolant tube materials, respectively, mainly due to high thermal conductivity and, in the case of tungsten, its high melting point. In this paper, recent understandings and future issues on responses of tungsten and Cu alloys to fusion environments (high particle flux (including T and He), high heat flux, and high neutron doses) are reviewed. This review paper includes; Tritium retention in tungsten (K. Schmid and M. Balden), Impact of stationary and transient heat loads on tungsten (J.W. Coenen and Th. Loewenhoff), Helium effects on surface morphology of tungsten (Y. Ueda and A. Ito), Neutron radiation effects in tungsten (A. Hasegawa), and Copper and copper alloys development for high heat flux components (C. Hardie, M. Porton, and M. Gilbert). (paper)

[en] The European Nuclear Young Generation Forum (ENYGF) is the event organised every 2 years within the European Nuclear Society - Young Generation Network (ENS-YGN) for European young professionals and students. It consists in 3 days of conferences (plenary sessions, workshops, panel sessions, technical and poster session), 1 day of technical tours and 1 day of cultural visits. ENYGF 2015 is dedicated to the dual aspect of the relationship between nuclear power and environment: the impact of nuclear activities on the environment and the contribution of nuclear energy to fight climate change. A great deal of this document is composed of the slides of the presentations