«ANNUAL REPORT Riga 2012 Annual Report 2011, Institute of Solid State Physics, University of Latvia. Editor: A.Krumins. Composed matter: A.Muratova. ...»
Latvian Hydrogen Association (LHA) was established on 2005 with aims to disseminate the ideas and conceptions about hydrogen economy between politicians and local municipalities; to promote and support the research, development and education activities in hydrogen energy technologies; to stipulate the realization of hydrogen energy demonstration projects and implementations of innovations in the market, trying to link business and research institutions. Five years experience shows that t is not easy to promote hydrogen technologies in country with proportion of renewable energy resources 30–35% already and with goal to increase them to 40% by 2020. LHA is trying to join hydrogen and renewable energy technologies in research, education and innovation activities. If all is clear in the science and topical areas of hydrogen related researches, then go to education issues is more difficult – necessary to teach not only children and students, but also politicians, government officials, businessmen and even traditional engineers from energy branch. Therefore LHA is organizing now the Latvian Hydrogen and Fuel Cell Technology Platform trying to identify and attract merchants from different companies.
Air quality in the city of Riga is evaluated from direct monitoring results and from accounting registered air pollutants in the city. It is concluded that from all air polluting substances listed in the European Commission directives, only nitrogen dioxide NO2 and particulate matter PM10 exceed the limits. In assessing the projected measures to improve air quality in Riga, it can be concluded that the implementation of cleaner fuels and improvements in energy efficiency of household and industrial sectors will decrease particle pollution, but measures in the transport sector will also contribute to reducing air pollution from nitrogen oxides. In assessing the projected measures to improve air quality in Riga, it can be concluded that the implementation of cleaner fuels and improvements in energy efficiency of household and the industrial sectors will give greater effect to decrease air pollution by particles, but the planned measures in the transport sector will contribute to reducing air pollution from nitrogen oxides.
FUNCTIONAL MATERIALS FOR RESISTIVE SWITCHING MEMORIESFP6 MATERA – ERA-NET Materials Project
The aim of the project is to develop the basic science and technology for new functional ternary oxides for the use as future resistive switching memories at the nanoscale level (20 nm). Since extended defects as dislocations or defect clusters with nanoscale dimensions are considered to be the single resistive switching units in doped ABO3-perovskites, one has to gain deeper understanding of the complex correlation between defect structure, elementary and defect distribution and switching properties.
Within the project, we indent to solve this challenging task by bundling the research activities of 3 different leading European groups which have a complementary expertise in the field of perovskite materials. The fabrication of SrTiO3 thin films, doped with different transition metals (Fe, Nb) have been performed by Pulsed Laser Deposition in the Forschungs-zentrum Jülich. In order to clarify the spatial distribution of doping atoms, thin films as well as single crystals have been analyzed by means of sophisticated spectroscopic techniques, e.g.
synchrotron based x-ray absorption spectroscopy (XAS) by the experimental partner at the Institute of Solid State Physics University of Latvia.
This work has been supported by ab initio calculations of the formation energies of defects and cation segregation by the theoreticians in the Institute of Solid State Physics University of Latvia.
For a given defect/cluster configuration, the resistive switching properties have been investigated in the Jülich group by means of the elaborate electrical characterization as well as by conductive-tip atomic force microscopy. In order to clarify the switching mechanisms, these investigations have be supported by scanning tunnelling microscopy (STM) with atomic resolution as well as by x-ray photoelectron spectroscopy (XPS) and scanning Auger electron spectroscopy (AES) in the Katowice group.
As a result of intensive research, a microscopic model for resistive switching was develop and a fabrication a thin film device with improved switching performance was proposed.
SOLAR THERMAL ENERGY STORAGE MATERIAL DEVELOPMENT USING
THE SOL-GEL AND VACUUM COATING TECHNOLOGY
The project aims to solar thermal energy storage material development based on significantly advanced technology for concentrated solar energy collector (CSEC). The project implementation activities associated with new, innovative CSEC absorption materials and production technologies that will provide alternative energy sources – to use solar radiation more efficiency. Development is based on the enamel and sol-gel technology as well as vacuumtechnology for CSEC collector multilayer coating manufacturing.
Innovative functional glassy coatings from the standpoint of modern technologies have a potential of novel and unexpected aspects, taking into account new physical properties, which is possible to achieve in the modern manufacturing process via control and manipulation of glassy coating at both macro- and nanoscale. We could mention here antireflective, low heat conductivity, electroconducting and other types of coatings, which play an increasing role in the energy effective applications, solar panels etc. In this Project Institute of solid state physics (Institute) will solve physical and technological problems, and create a new commercial products for export with a high added value.
Many modern energetical devices employ optically transparent coatings produced from electroconducting oxides (TCO) as one of key elements. There emerges a commercial possibility to develop equipment for production of such TCO coatings. Previously such the equipment for production of TCO coatings was based on expensive indium oxide (ITO) as a starting material for production of coatings with a high quality. The Institute wants to develop novel basic technologies, with much cheaper TCO coating production, which could be incorporated into the new coating quipments.
In the framework of the project the Institute plans to develop a new sputtering technology and solution investigations for different TCO materials on the basis of High Power Impulse Magnetron Sputtering (HIMIPS), and to investigate basic industrial operation principles, which could be employed as effective and economically profitable technology in AS „Sidrabe” in order to develop vacuum coating devices. Our Project will result in a complicated industrial research, in order to clarify a possibility to use HIPIMS sources for sputtering and developing cheap and high quality vacuum coatings.
DEVELOP AN INNOVATIVE TECHNOLOGY FOR SOLAR-GRADE SILICON BY
ELECTRON BEAM METHOD
Development of innovative technology to obtain a high purity silicon suitable for production of solar elements is performed in the frame of ERAF Project. Remelting and purification of metallurgical silicon using electron-beam technology have been made. Samples of silicon prepared with this technology were investigated using mass-spectrometry method (ICP-MS), Scaning Electrom Microscope, X-ray difractometer, Raman spectrometer, FTIR spectrometer.
Results: Metallurgical silicon with purity of 4N, produced in Kazakhstan is sufficient for production of Solar grade Silicon if we use the electron-beam technology. Oxidative refining carried out using of electron-beam remelting has significant advantage over merely technology by vacuum EB remelting. This method allows us to get out of silicon with a purity of 4N, the Solar Grade Silicon with purity of 6N (99,9999%) that can be used for Solar energetics. The modelling of the melting process of silicon by electron beam in a watercooled cruicible have been performed. A simplified model for modeling the melt flow and heat transfer under law –frequency traveling magnetic field influence in the crucible with electron beam heating is described
TRITIUM RELEASE FROM THE PEBBLE-BED ASSEMBLIES NEUTRONIRRADIATED BERYLLIUM PEBBLES UNDER ACTION OF TEMPERATUREA. Vītiņš, G. Ķizāne*, A. Matīss*, E. Pajuste*, V. Zubkovs* * Institute of Chemical Physics, University of Latvia Beryllium pebbles are foreseen as a neutron multiplier to ensure sufficient tritium breeding in a ceramic breeder in a blanket of a future fusion power reactor. Helium and tritium are produced in beryllium as a result of neutron-induced transmutations. One of tasks of blanket designs is to reduce tritium inventory in the beryllium pebbles.
In this study, we present results on tritium release from the beryllium pebbles (∅≈1 mm) irradiated for 294 full power days from 17 April 2003 to November 2004 to the neutron fluence of 3-4×1025 m-2 (E0.1 MeV) at temperature 523-823 K in the pebble-bed assemblies (PBA) experiment in the high flux reactor at Petten, the Netherlands [1,2].
This study is a report on post irradiation tritium release experiments under action of both temperature ramps of β=2.3-4.8 K/min from room temperature to 1310-1520 K and anneals at a constant temperature of 1000-1180 K for 4-23 h on the beryllium pebbles in the flow of the purge gas He + 0.1% H2 of 14-15 L/h. One PBA Be pebble was investigated in each tritium release experiment.
Fig. 1. Tritium release rate and tritium sum Fig. 2. Degrees of detritiation of the PBA Be release from the PBA Be pebbles heated at pebbles achieved as a result of annealing the given temperature: curve 1 – a ramp of up under the given temperature and time. Series to 36 K/min to an anneal temperature of 1 (dark grey) – the degree of detritiation (27K; curve 2 – a ramp of up to 41 75%) achieved before the start of the burst K/min to an anneal temperature of 999-1001 release. Series 2 (white) - the degree of K. The PBA Be pebbles had the following detritiation (12%) achieved before the start of masses (mg), final values of the tritium sum the burst release in the second annealing.
release for 1 g of the sample (GBq/g) and Series 3 (light grey) – the degree of final values of the tritium fractional sum detritiation (17-73%) achieved after the start release (%):1 – 0.73, 2.09, 74.8%; 2 – 1.21, of the burst release.
1.96, not determined.
Tritium release from PBA Be pebbles on annealing at 1045 and 1000 K for 22.4 h is shown in Fig. 1. The two pebbles investigated under the temperature programmes given in Fig. 1 had quite different tritium release patterns. One noticeable difference is a higher maximum tritium release rate for the pebble annealed at lover temperature (curve 2) than that at higher temperature (curve 1). At 1045 K, no burst release of tritium took place (curve 1). However, after annealing at 1000 K, burst release of tritium took place after cooling down to 560 K (curve 2). The pebble annealed at 1000 K (curve 2) was not dissolved in acid, but was used for microscopy, where it was found that visible cracks were formed and the porosity started to appear in the pebble. Degrees of detritiation achieved on annealing are summarized in Fig. 2.
Contributions of the tritium release by atomic diffusion before the burst release and the tritium release after the burst release event are estimated in the total degree of detritiation.
1. The total tritium inventory in the PBA Be pebbles was found to be 2-4 GBq/g. It may be considered as a reasonable estimation for tritium accumulation in the helium-cooled pebble bed test blanket module (HCPB TBM) Be pebbles for the neutron fluence achieved at the end of PBA irradiation 1.5-2 × 1025 m-2 (E 1 MeV).
2. Two distinct stages of tritium release – a stage of gradual release and a stage of abrupt release peaks are clearly distinguishable in the tritium release of the PBA Be pebbles on annealing. These two stages may be related to the tritium release by atomic diffusion and bubble venting respectively.
3. Increasing the temperature of the beryllium pebble bed at neutron irradiation from 523-823 K to 1000-1045 K may reduce the tritium inventory in the beryllium pebbles by factor of ≥ 2.
4. Assuming that the tritium release at the end parts of the anneals is limited by diffusion if the burst release is absent, the effective values of the tritium diffusion coefficients were determined for the PBA Be pebbles as 2.6 × 10-13 m2/s for 1045 K and 5.1 × 10-13 m2/s for 1089 K.
Acknowledgement: This study was carried out with EFDA financial support (Technology Task TW5-TTBB-006-D08).
References:  J. G. van der Laan et al, Fusion Eng. Des. 61-62 (2002) 383.
 A. Ying et al, J. Nucl. Mater. 367–370 (2007) 1281.
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