Activation Analysis for a He/LiPb dual Coolant Blanket for DEMO Reactor

The objective of the Spanish national project TECNO_FUS is to generate a conceptual design of a DCLL (Dual-Coolant Lithium-Lead) blanket for the DEMO fusion reactor. The dually-cooled breeding zone is composed of He/Pb-15.7 6Li and SiC as liquid metal flow channel inserts. Structural materials are ferritic-martensitic steel (Eurofer-97) for the blanket and austenitic steel (316LN) for the Vacuum Vessel (VV). The goal of this work is to analyze the radioactive waste production by the neutron-induced activation and the back-end of the blanket and the VV (SS316LN) materials (Eurofer, SiC, LiPb, and SS316LN). Furthermore, the radioactive waste production in the cryostat (SS316LN) and the bioshielding (concrete) has been estimated. Following the current approach to the back-end of the materials in fusion facilities, the radioactive waste has been subdivided according to the activity-level classification (EW, exempted waste, LILW, low and intermediate level waste, and HLW, high level waste) and according to the radiological complexity of operations (handling and cooling). The activation calculations have been carried out with the ACAB code

MULTIFUNCTION IS NOT ENOUGH AN APROACH TO A NEW CONCEPT IN URBAN SPACE LE TERROIR

The idea is to analyse two urban spaces located close together (Chiado and Carmo), in order to evaluate the differences between them, namely: why is it that before two urban spaces of multifunctional characteristics the touristic impact can be so diverse? The answer is almost spontaneous: the heritage in all its forms - historic, cultural, architectonic, literary, artistic… etc. These variables are, undoubtedly, meaningful, but still there is more to it. This is where the terroir concept comes in. Usually applied in vitiviniculture, it defines in a gestalt way the territory, distinguishing the wine from one place to another. The concept itself summarizes something that often cannot be explained: for instance, why do two wines produced in territories with seemingly the same characteristics achieve unequal success? Besides the controllable elements/factors, other interactions arise which surpass the controllable and contribute to the presence of a unique taste. With the territory/urban space the same thing happens, there are elements that interact with each other changing the whole: it’s the terroir

Inelastic scattering of fast electrons in nanowires: A dielectric formalism approach

The excitations produced by fast electrons impinging perpendicularly on both metallic and semiconductor cylindrical nanowires are investigated within the framework of dielectric theory. The dependence of the electron energy-loss spectra (EELS) on the nanowire radius is studied in detail, and so is the spatial extension of the induced-charge fluctuations associated to the modes that are excited during the loss process. The limits of applicability of dielectric theory to nanowires are discussed. In particular, comparison between the present theory and EELS measurements performed with silicon nanofibers support the use of dielectric theory at the scale of a few nanometers in diameter, and it is shown that this positive result is justified in terms of the longitudinal pattern of the induced surface plasmons. Finally, the effect of nanowire termination on the electron energy-loss probability for electrons passing near the edge is calculated using the boundary charge method, showing that the range of this effect can extend up to tens of nanometers for low-energy m=0 modes.Support from the Basque government and Basque Country University is acknowledged. One of the authors E.O. also acknowledges the Spanish Ministerio de Educacion y Cultura for financial support under Contract No. PB98-0780-C02.Peer reviewe

Optimización de uniones y estructuras de autobuses

El objetivo principal del proyecto de investigación presentado es el de obtener una mejorar en el comportamiento y la predictibilidad de las tensiones de los modelos FEM de vehículos de grandes dimensiones para el transporte de pasajeros (autobuses y autocares). Dadas las dimensiones de estos vehículos y el tipo de estructura de los mismos (tubular de sección rectangular hueca) los modelos más adecuados desde el punto de vista técnico, económico y de coste de modelización computacional son los generados con elementos de tipo viga. Dichos elementos debido a la simplicidad de su formulación presentan una serie de limitaciones en la caracterización del comportamiento de las uniones (infinitamente rígidas), debido a esto los modelos de autobuses realizados con este tipo de elementos presentan mayores rigideces estructurales. Teniendo en cuenta lo anteriormente mencionado las estimaciones de vida a fatiga o la estimación de las tensiones se ven afectadas. Para resolveré este problema se han realizando una serie de investigaciones mediante modelización y experimentación para diferentes modelos de uniones que se encuentran de manera frecuenta en las estructuras de autobuses urbanos. Por otra parte fue ideada una metodología y se realizo un programa mediante el cual se pueden realizar de manera rápida simulaciones para una serie entera de configuraciones de los parámetros del modelo con elementos finitos: tipos de elementos utilizados, tipo de mallado, dimensión del mallado características de las constantes reales. Conjuntamente fueron realizadas una serie de análisis modales para diferentes uniones en las cuales se intento aislar y evidenciar las diferencias de comportamiento vibracional influenciado exclusivamente por la configuración de la unión. Los resultados obtenidos serán utilizados para poder realizar un modelo con elementos finitos que reproduzca de manera más real el comportamiento de las uniones rígidas que se utilizan en los autobuses y autocares (uniones soldadas

Propagation of nuclear data uncertainties in transmutation calculations using ACAB code

The assessment of the accuracy of parameters related to the reactor core performance (e.g, keff) and fuel cycle parameters (e.g. evolution/transmutation calculations) due to the uncertainties in the basic nuclear data (ND) is a critical issue. In performing this assessment, different error propagation techniques (adjoint/forward sensitivity analysis procedures and/or Monte Carlo technique) can be used to address by computational simulation the systematic propagation of uncertainty on the evaluation of the final responses. To perform this uncertainty evaluation the ENDF covariance files (variance/correlation in energy and cross-reactions-isotopes correlations) are required. In this paper, we assess the impact of ND uncertainties on the isotopic prediction for a conceptual design of a modular European Facility for Industrial Transmutation (EFIT) for a discharge burnup of 150 GWd/tHM. The complete set of uncertainty data for cross sections (EAF2007/UN, SCALE6.0/COVA-44G), radioactive decay and fission yield data (JEFF-3.1.1) are processed and used in ACAB code

IoT-based platform for automated IEQ spatio-temporal analysis in buildings using machine learning techniques

Financiaciado para publicación en acceso aberto: Universidade de Vigo/CISUGProviding accurate information about the indoor environmental quality (IEQ) conditions inside building spaces is essential to assess the comfort levels of their occupants. These values may vary inside the same space, especially for large zones, requiring many sensors to produce a fine-grained representation of the space conditions, which increases hardware installation and maintenance costs. However, sound interpolation techniques may produce accurate values with fewer input points, reducing the number of sensors needed. This work presents a platform to automate this accurate IEQ representation based on a few sensor devices placed across a large building space. A case study is presented in a research centre in Spain using 8 wall-mounted devices and an additional moving device to train a machine learning model. The system yields accurate results for estimations at positions and times never seen before by the trained model, with relative errors between 4% and 10% for the analysed variables.Ministerio de Ciencia, Innovación y Universidades | Ref. RTI2018-096296-B-C2Ministerio de Ciencia, Innovación y Universidades | Ref. FPU17/ 01834Ministerio de Ciencia, Innovación y Universidades | Ref. FPU19/01187Universidad de Vigo | Ref. 00VI 131H 641.0

Methodology to address radioprotection and safety issues in the IFMIF/EVEDA accelerator prototype

In the IFMIF/EVEDA accelerator prototype, deuterons (with energies up to 9 MeV) interact with the materials of the accelerator components due to beam losses and in the beam dump, where the beam is stopped. The productions of neutrons/photons together with radioactive inventories due to deuteron-induced reactions are some major issues for radioprotection and safety assessment. Here, we will focus on the proposal of a computational approach able to simulate deuteron transport and evaluate deuteron interactions and production of secondary particles with acceptable precision. Current Monte Carlo codes, such as MCNPX or PHITS, when applied for deuteron transport calculation, use built-in semi-analytical models to describe deuteron interactions. These models are found unreliable in predicting neutron and photon generated by low energy deuterons, typically present in the IFMIF/EVEDA prototype accelerator. In this context, a new computational methodological approach is proposed based on the use of an extended version of current MC codes capable to use evaluated deuteron libraries for neutron (and gamma) production. The TALYS nuclear reaction code is found to be an interesting potential candidate to produce the evaluated data for double-differential neutron and photon emission cross sections for incident deuterons in the energy range of interest for IFMIF/EVEDA applications. The recently-released deuteron Talys-based Evaluated Nuclear Data Library, TENDL-2009, is considered a good starting point in the road to achieve deuteron data files of enough quality for deuteron transport problems in EVEDA. Unfortunately, current Monte Carlo transport codes are not able to handle light ion libraries except for protons. To overcome this drawback the MCNPX code has been extended to handle deuteron (also triton, helion and alpha) nuclear data libraries. In this new extended MCNPX version called MCUNED, a new variance reduction technique has also been implemented for the production of secondary particles induced by light ions nuclear reactions, which allow reducing drastically the computing time needed in transport and nuclear response function calculations. Verification of these new capabilities for Monte 2 Carlo simulation of deuteron transport and secondary products generation included in MCUNED is successfully achieved. The existence of the MCUNED code allows us for the first time testing the deuteron crosssection TENDL package by simulation of integral experiments. Some preliminary efforts are addressed to compare existing experimental data on thick target neutron yields for Copper with those computed by the MCUNED code using TENDL cross sections

Brechas de rendimiento en maíz de verano: análisis de la contribución de cambios en el manejo

El estudio de brechas entre el rendimiento potencial (RP) y el rendimiento de cultivos alcanzado por productores (RA) bajo una determinada combinación de ambiente (A) y manejo agronómico (MA) permite identificar vías para incrementar la productividad y la eficiencia en el uso de recursos1, 2. Si RA con la tecnología de los productores es inferior al 80% del RP3, es esperable que mejoras en la productividad puedan lograrse mediante cambios en el MA2. En la actualidad, entre el 40-60% del maíz producido en Argentina es cultivado en fechas de siembra tardías hacia el inicio del verano4, cuando la probabilidad de estreses hídricos y térmicos por alta temperatura es menor5. Estimaciones recientes mediante modelos de simulación proponen que el RP del maíz tardío en el centro de Argentina varía entre 14 y 16 tn ha-1, sugiriendo importantes brechas respecto a los rendimientos actualmente logrados6. El objetivo de este trabajo fue cuantificar el RP, el RA y la brecha entre ambos tomando como caso de análisis a maíces cultivados en el norte de Córdoba. En particular, se indagó si la magnitud de las brechas difiere bajo la interacción entre manejo y genotipos de maíz.INTA. EEA Manfredi.Fil: Ogando, Federico A. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi. Agronomìa. Grupo Manejo de Cultivo. ArgentinaFil: Raspa, Francisco Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi. Agronomìa. Grupo Manejo de Cultivo. ArgentinaFil: Vega, Claudia Rosa Cecilia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi. Agronomìa. Grupo Manejo de Cultivo. ArgentinaFil: Pita, Marcos. Bruno Tesan S.A., La Puerta, Córdoba. Argentin

Optimized design of local shielding for the IFMIF/EVEDA beam dump

This paper describes the local shielding design process of the IFMIF/EVEDA Beam Dump and the most relevant results obtained from the simulations. Different geometries and materials have been considered, and the design has been optimized taking into account the origin of the doses, the effect of the walls of the accelerator vault and the space restrictions. The initial idea was to shield the beam stopper with a large water tank of easy transport and dismantling but it was shown to be insufficient to satisfy the dose limit requirements, basically due to photon dose, and hence a denser shield combining hydrogenous and heavy materials was preferred. It will be shown that, with this new shielding, dose rate outside the accelerator vault during operation comply with the legal limits and unrestricted maintenance operations inside most of the vault are possible after a reasonable cooling time after shutdown