[en] A mathematical model has been set up to assist gaining insight into the amount of fission products released into the environment during rated failure-free reactor operation. In this model, the radionuclide balance is based on cumulative yields from the fission of ²³⁵U. The number of fission events is determined from the reactor power output. The sources of fission products in the coolant, considered in the treatment, are defects in the fuel element cladding and recoil from surface contamination. Adapted for implementation on an IBM PC, the model is employed at the nuclear power plant in Jaslovske Bohunice. (Z.M.). 2 figs., 5 refs

No abstract available

[en] We report on the use of genomic approaches to identify pivotal genes in induced citrus mutants. Citrus is the most economically important fruit crop in the world and Spain is the first fresh citrus producer. The survival of the citrus industry is critically dependent on genetically superior cultivars but improvements in fruit quality traits through traditional techniques are extremely difficult due to the unusual combination of biological characteristics of citrus. Genomic science, however, holds promise of improvements in breeding. In this work, we reported the successful identification of genes included in hemizygous deletions induced by fast neutron irradiation on Citrus clementina. Microarray-based CGH was used to identify underrepresented genes in a citrus mutant that shows color break delay. Subsequent confirmation of gene doses through quantitative PCR and comparison of best hits of putative deleted citrus genes against annotated genomes from other eudicots, specially poplar, enabled the prediction that these genes were clustered into a 700 kb fragment. The availability of Citrus BAC end sequences helped to draw a partial physical map of the deletion. Furthermore, gene content and order in the deleted segment was established by PCR location of gene hits on the physical map. Finally, a lower chlorophyll a/b ratio was found in green tissues from the mutant, an observation that can be related to the hemizygous deletion of a ClpC-like gene, coding a putative subunit of a multifunctional protease complex located into the chloroplast. Analysis of gene content and order inside this Citrus deletion led to the conclusion that microsynteny and local gene colinearity with Populus trichocarpa were higher than with the phylogenetically closer Arabidopsis thaliana genome. In conclusion, a combined strategy including genomics tools and induced citrus mutations has been proved to be a successful approach to identify genes with major roles in citrus fruit development. (author)

[en] We report on the use of genomic approaches to identify pivotal genes in induced citrus mutants. Citrus is the most economically important fruit crop in the world while Spain is the first fresh citrus producer. The survival of the Citrus industry is critically dependent on genetically superior cultivars but improvements in fruit quality traits through traditional techniques are extremely difficult due to the unusual combination of biological characteristics of citrus. Genomic science, however, holds promise of improvements in breeding. In this work, we reported the successful identification of genes included in hemizygous deletions induced by fast neutron irradiation on Citrus clementina. Microarray-based CGH was used to identify underrepresented genes in a citrus mutant that shows color break delay. Subsequent confirmation of gene doses through quantitative PCR and comparison of best hits of putative deleted citrus genes against annotated genomes from other eudicots, specially poplar, enabled the prediction that these genes were clustered into a 700 kb fragment. The availability of Citrus BAC end sequences helped to draw a partial physical map of the deletion. Furthermore, gene content and order in the deleted segment was established by PCR location of gene hits on the physical map. Finally, a lower chlorophyll a/b ratio was found in green tissues from the mutant, an observation that can be related to the hemizygous deletion of a ClpC-like gene, coding a putative subunit of a multifunctional protease complex located into the chloroplast. Analysis of gene content and order inside this Citrus deletion led to the conclusion that microsynteny and local gene colinearity with Populus trichocarpa were higher than with the phylogenetically closer Arabidopsis thaliana genome. In conclusion, a combined strategy including genomics tools and induced citrus mutations has been proved to be a successful approach to identify genes with major roles in citrus fruit development. (author)

[en] Highlights: • Cracking damage on some JET divertor outer targets (Tile 6) was found after high power plasma pulses performed sweeping the strike point. • Only thermal energy and maximum temperature limits are imposed on PFCs during JET Operation. • Under realistic time and space-varying heat loads, thermally-induced bending of Tile 6 enhances the formation and propagation of cracks. • The critical parameter affecting the maximum toroidal stress is the strike point position as it has implications on the thermal energy deposited in the tile. • Cracks are unavoidable at energy levels above 35 MJ, but the tie rods will prevent complete tile failure and allow for remote maintenance. -- Abstract: The next D-T campaign will push the JET ITER-like wall to high divertor power and energy levels. During the 2016 campaign, Strike Point (SP) sweeping permitted relevant H-mode scenarios without exceeding the temperature limits imposed by JET Operation Instructions (JOIs). In the subsequent shutdowns, six outer divertor tungsten-coated 2D carbon fibre composite tiles were found to have inter-laminar cracks. Here we describe the results of a 3D thermo-mechanical analysis aimed at understanding the origin of the cracks. A sensitivity assessment has been carried out on the temperature time-evolution of a realistic tile 3D model during high power pulses, both with fixed and sweeping SPs. Time and space-varying heat flux density loads on the divertor have been calculated using different techniques for reconstructing the power footprint. The results have been benchmarked against the temperature measurements by high resolution infrared diagnostic systems. The study confirmed the source of the cracks and their localization in the upper part of the tile, giving inter-laminar tension higher than the Ultimate Tensile Stress. Plasma input power, radial location of the SP and sweeping amplitude play an important role on the stress field whose maximum value strongly depends on the SP location. Their influence on the maximum stress value has been investigated and optimized to maximize the performance of divertor tiles without exceeding the limits on input energy and maximum surface temperature imposed by the JOIs.

[en] Highlights: ► Article is focused on the beam dump cooling system from the IFMIF-EVEDA accelerator. ► Total power of 1.125 MW deposited by the 9 MeV, 125 mA deuteron beam. ► Variable channel width to meet the heat extracting criteria. ► Cooling circuit design based on keeping the cooling bulk close to water boiling point. ► 3D fluid analysis of the most problematic regions of the cooling channel. - Abstract: The IFMIF–EVEDA beam dump is designed to stop a 9 MeV, 125 mA continuous wave deuteron beam that deposits along its surface a total of 1.125 MW. The beam dump design is based on a 2.5 m long copper cone whose inner surface absorbs the beam. This piece is cooled by water flowing at high velocity through the annular channel formed between it and a second piece (shroud) made of four truncated cones of slightly different slopes. In this paper the beam dump cooling system will be briefly described, and the relevant 1D and 3D results will be presented paying especial attention to the computational fluid dynamics results.

[en] The EUROfusion Road-map to the Realisation of Fusion Energy outlines a European programme to produce concepts for a demonstration power plant, known as DEMO. It is the successor to the 13 billion ITER machine, currently being built in Cadarache, France. ITER will be the first fusion experiment to deliver a significant net output of energy. DEMO will build upon the experience gained in ITER and will demonstrate the technologies needed to deliver electricity to the grid. To be successful, a commercially viable power station requires high availability and must meet stringent nuclear safety requirements. However, due to neutron damage to materials, a fusion power station such as DEMO will also require the periodic exchange of the plasma facing components. To meet these requirements, components must be exchanged rapidly and in a highly controlled, safe manner. These requirements are met by the use of Remote Handling technologies, but present significant challenges due to the component scale and the hostile environment. RACE, the UKAEA's centre of excellence for remote handling, is leading a work package for EUROfusion to develop technologies for DEMO. The current scheme for blanket replacement is described in this poster. Blankets will be extracted through the upper ports on the tokamak using a cask system. This keeps the radioactive components isolated from the wider environment during maintenance. The vertical transporter is the major component of the interface cask. This has the capability to carry interchangeable end-effectors. Recovery and rescue scenarios are also improved due to the modular nature of the system and the access points created by the transport cask apertures

[en] In this paper, we propose a geometric integrator for nonholonomic mechanical systems. It can be applied to discrete Lagrangian systems specified through a discrete Lagrangian L_d: Q x Q → R, where Q is the configuration manifold, and a (generally nonintegrable) distribution D subset of TQ. In the proposed method, a discretization of the constraints is not required. We show that the method preserves the discrete nonholonomic momentum map, and also that the nonholonomic constraints are preserved in average. We study, in particular, the case where Q has a Lie group structure and the discrete Lagrangian and/or nonholonomic constraints have various invariance properties, and show that the method is also energy-preserving in some important cases

No abstract available

[en] The LIPAC beam dump cooling circuit has been modelled by means of TRACT (TRansport and ACTivation) code. TRACT simulates the flow and isotope transport inside a network of 1-D channels. The cooling circuit consists of the beam dump (inner cone and shroud made of EDP Cu (electrodeposited copper) and the cylinder made of SS304L), the piping from the cooling skid to the beam dump cell and the cooling skid itself composed of the heat exchanger, the purifying loop and the pump. Corrosion is an issue that deserves attention because of radioprotection reasons and because it could affect the cartridge thermomechanical performance. A simulation with TRACT for a water pH of 7 at the beam dump entrance has been performed, showing corrosion rates (< 1 g/(m² year)) which do not compromise the beam dump performance