Time filter

Source Type

Husinec, Czech Republic

Di Gabriele F.,Centrum vyzkumu Rez | Soukup O.,University of West Bohemia | Houdkova S.,University of West Bohemia | Karnik D.,UJV Rez a.s
International Conference on Nuclear Engineering, Proceedings, ICONE | Year: 2014

The use of heavy liquid metals (HLM), such as Lead, Pb, is being considered as a coolant in Generation IV fast Reactors. However, structural materials suffer significant damage when in contact with HLMs. Both austenitic and ferritic-martensitic steels are considered and are susceptible to corrosion and/or degradation of mechanical properties. One of the approaches to mitigate erosion/corrosion problems is the use of coatings. This is a layer of a different chemical composition between the base material and the liquid metal coolant in order to prevent the bulk metal from corrosive effects. Coatings are proposed as a valid protection against high temperature damage in this environment. Their capability to grow more stable and protective oxides, by introducing the oxide forming elements (e.g. Al, Si,⋯) in higher amount, is proven to be an effective alternative to material engineering. For this specific application, several coatings deposition techniques and compositions have been proposed and tested. In this work the High Velocity Oxygen Fuel, HVOF, combined with laser melting was selected for deposition of FeCrAlY coatings. The combination of the two technologies lead to a compact and adherent coating with an enriched content of Al. The method was evaluated in terms of the corrosion resistance of the coating and also its effect on the microstructure of the substrate alloy. Several attempts were carried out to modify spraying and laser parameters in order to minimise the effect on the substrate and keep the protective properties. Results are discussed in terms of deposition parameters and protection characteristics. Copyright © 2014 by ASME.

Chersola D.,University of Genoa | Lomonaco G.,University of Genoa | Mazzini G.,Centrum vyzkumu Rez
International Conference on Nuclear Engineering, Proceedings, ICONE | Year: 2014

This paper reports the results of a comparison among JEFF and ENDF/B datasets when used by SERPENT and MONTEBURNS codes on a GFR-like configuration. Particularly, it shows a comparison between the two Monte Carlo based codes, each one adopting three different cross sections dataset, namely JEFF-3.1, JEFF-3.1.2 and ENDF/BVII. 1. Calculations have been carried out on the Allegro reactor, i.e. an experimental GFR-like facility that should be built in EU as GFR demonstrator. Results concern nuclear parameters as effective multiplication factor and fluxes, as well as the atomic densities for some important nuclides versus burnup. Copyright © 2014 by ASME.

Matejicek J.,Czech Institute of Plasma Physics | Vilemova M.,Czech Institute of Plasma Physics | Hadraba H.,Academy of Sciences of the Czech Republic | Di Gabriele F.,Centrum vyzkumu Rez | And 5 more authors.
Nuclear Materials and Energy | Year: 2016

Materials for the plasma facing components of future fusion reactors will be subjected to complex loading and various forms of interaction with low Z species (hydrogen isotopes and helium). The divertor components will be among the most intensely loaded, as they will have to transfer heat loads up to 10-20MW/m2. Besides the plasma facing surface being irradiated by highly energetic deuterium, tritium and helium particles from the burning plasma, the opposite surface will be exposed to a cooling medium at elevated temperature. Helium- and water-based cooling systems are currently being considered. While tungsten is the prime candidate material for the plasma facing components, in the helium-cooled divertor designs, it is also foreseen as a structural material, together with ferritic-martensitic steels. The behavior of these materials in He atmosphere at elevated temperatures has been little studied thus far, and therefore is the subject of the current work.A number of W-based materials (pure tungsten and some of its alloys) prepared by powder metallurgy techniques was exposed to He atmosphere at 720. oC and 500. kPa for 500. h. Morphological surface changes were observed by SEM, chemical and phase composition was analyzed by EDS and XRD, respectively. The internal microstructure was observed by a combination of SEM, FIB and TEM techniques. Mechanical properties were determined by instrumented indentation. Some alloys developed a thin oxide layer, in some cases new morphological features were observed, while some samples remained mostly intact. The observed changes are correlated with specific compositions and microstructures. © 2016 The Authors.

Boccaccini L.V.,Karlsruhe Institute of Technology | Aiello G.,CEA Saclay Nuclear Research Center | Aubert J.,CEA Saclay Nuclear Research Center | Bachmann C.,EUROfusion | And 11 more authors.
Fusion Engineering and Design | Year: 2016

The design of a DEMO reactor requires the design of a blanket system suitable of reliable T production and heat extraction for electricity production. In the frame of the EUROfusion Consortium activities, the Breeding Blanket Project has been constituted in 2014 with the goal to develop concepts of Breeding Blankets for the EU PPPT DEMO; this includes an integrated design and R&D programme with the goal to select after 2020 concepts on fusion plants for the engineering phase. The design activities are presently focalized around a pool of solid and liquid breeder blanket with helium, water and PbLi cooling. Development of tritium extraction and control technology, as well manufacturing and development of solid and PbLi breeders are part of the programme. © 2016.

Domalapally P.K.,Centrum vyzkumu Rez | Entler S.,Centrum vyzkumu Rez
Acta Polytechnica | Year: 2015

Some components of fusion reactors receive high heat fluxes either during startup and shutdown, or while the machine is in operation. This paper analyzes various ways of enhancing heat transfer using helium and water for cooling these high heat flux components. Conclusions are then drawn to decide on the best choice of a coolant for use in the near term and in the long term. © Czech Technical University in Prague, 2015.

Discover hidden collaborations