Casa Huarte: José Antonio Corrales y Ramón Vázquez Molezún. El concepto de lo experimental en el ámbito doméstico

Se plantea aquí el estudio de la Casa Huarte (1966) como un experimento doméstico -así lo concibió el matrimonio Huarte desde la libertad de acción y la entrega al talento de los arquitectos- que sintetizó los principios de los proyectos de la primera etapa de la obra de José Antonio Corrales (1921-2010) y Ramón Vázquez Molezún (1922-1993): paisaje construido, topografía modificada, basamento pesado y arraigado, cubierta ligera flotante y abstracción compositiva. La considerada vivienda experimental del siglo XX estaba asociada a estructuras familiares reducidas, como mucho formadas por un matrimonio con dos hijos. La Casa Huarte, sin embargo, pertenece a un grupo no reconocido de viviendas experimentales de gran formato, que aportaban -en entornos de vida socio-familiar no convencionales- una complejidad funcional, espacial y de relaciones interpersonales que la vivienda mínima no tenía. La Casa Huarte supuso un punto de inflexión en la carrera de Corrales y Molezún, culminando una primera etapa donde se concentraron sus obras más destacadas: Instituto en Herrera de Pisuerga (1956), Residencia de Miraflores (1958) y Pabellón de Bruselas, en sus versiones belga (1958) y española (1959). El proyecto de la Casa Huarte adelantó estrategias que aplicarían en proyectos posteriores -dinamismo del plano horizontal, visuales diagonales, entrada tangencial- y culminó la evolución de un tipo de vivienda que Corrales y Molezún comenzaron a investigar diez años antes. Entre 1956 y 1961 proyectaron cuatro viviendas (Casa Remírez Escudero, Casa Álvarez Mon, Casa Gómez Acebo y Casa Cela) que anticiparon soluciones y situaciones presentes y perfeccionadas en la Casa Huarte. Corrales aseguraba que si la vida es contradictoria la arquitectura también debería serlo. La Casa Huarte es compleja y contradictoria funcional y espacialmente, homogeneizada por una imagen exterior rotunda y atractiva de juegos de volúmenes maclados. El proyecto se muestra así de contundente detrás de habilidosas maniobras tectónicas que ocultan las muchas complejidades y contradicciones aparentemente inapreciables. Estas maniobras confunden la imagen que de la casa se tiene. Debajo de su manto cerámico de reminiscencias vernáculas - híbrido de casa castellana y arquitectura nórdica- se esconde una obra de arquitectura avanzada tecnológicamente. La tesis se desarrolla en cuatro apartados denominados procesos, por lo que tienen de secuencia en el desarrollo de la investigación. Estos procesos son: proceso descriptivo, proceso analítico, proceso interpretativo y proceso poético. Después del necesario e introductorio proceso descriptivo, el cuerpo central de la tesis -que contiene los procesos analítico, interpretativo y poético- sigue un guión marcado por la defensa de la categoría experimental de la Casa Huarte. Se han tratado los conceptos más característicos de la vivienda, desde los más generales a los más específicos divididos en cuatro grupos: Composición, volumen y espacio; El patio como lugar; El jardín: horizonte construido; Domesticidad del mundo interior; y Euritmia: materia y espíritu Molezún aseguraba que para entender una obra de arquitectura había que dibujarla. La Casa Huarte ha sido redibujada en sus tres etapas fundamentales: el proyecto de ejecución (marzo 1965), la casa acabada (noviembre 1966) y el estado actual (2012). El estudio y análisis se centra en la casa construida, por ser la realidad tridimensional en que el proyecto se nos manifiesta. La documentación gráfica del estado actual de la vivienda es inédita y ha sido posible gracias a múltiples inspecciones de la Casa Huarte en visitas facilitadas por las hijas de Jesús Huarte, actuales propietarias de la vivienda. Esta documentación nos permite constatar las alteraciones sobre la obra construida y conocer que modificaciones serían necesarias para recuperar el estado original de la casa. La Casa Huarte es una obra singular, una de las cinco viviendas unifamiliares pertenecientes a la Arquitectura del Movimiento Moderno en España y Portugal de mayor interés registrada por el Docomomo Internacional. Su futuro es incierto, se encuentra deshabitada y en venta. La familia Huarte ha cumplido con creces la misión de conservar su patrimonio. Es pertinente reivindicar su vigencia como obra de referencia de la arquitectura española del siglo XX, y, de esa manera, evitar que caiga en el olvido y el abandono. ABSTRACT The Huarte House (1966) will be analysed as a domestic experiment – that is how the Huarte’s conceived it, putting their faith in the architects – that synthesized the principles from the projects of the first phase of the work of Jose Antonio Corrales (1921-2010) and Ramón Vázquez Molezún (1922-1993): built landscape, modified topography, heavy and rooted base, light, floating roof and abstraction in composition. The experimental house of the 20th century was associated with small nuclear families of at the most a couple and two children. The Huarte House belongs to a group of non-recognised experimental houses of a larger size -and more unconventional familial settings- that lent themselves to greater functional, spatial and interpersonal complexity than their smaller counterparts. The Huarte House represented a turning point in the careers of Corrales and Molezún, capping a first phase that includes their most prominent work: the Institute at Herrera de Pisuerga (1965), the Residence at Miraflores (1958) and the Brussels Pavilion, in its Belgian (1958) and Spanish (1959) version. The project for the Huarte house anticipated strategies which they would apply to later projects: dynamism of the horizontal plane, diagonal visuals, and tangential entrances. It was also the culmination of the evolution of a type of house that Corrales and Molezún had started to investigate ten years earlier. Between 1956 and 1961 they designed four houses (Ramírez Escudero House, Álvarez Mon House, Gómez Acebo House and Cela House) that anticipated the solutions applied and perfected in the Huarte House. Corrales believed that if life was contradictory architecture should be so too. The Huarte House is complex and contradictory. Corrales and Molezún homogenised the project under a bold and attractive image of intersecting volumes. The project appears emphatic thanks to skilful tectonic manoeuvres that conceal the many complexities and contradictions so that they become imperceptible. These manoeuvres confound the image of the house. Under its ceramic blanket of vernacular reminiscences (a mixture of Castilian house and Nordic architecture) lies a technologically advanced piece of architecture. The thesis is organised in four chapters named ‘processes’ in reference to their sequence in the development of the research. These processes are: descriptive process, analytic process, interpretative process and poetic process. After the necessary and introductory descriptive process, the main body of the thesis, which encompasses the analytical, interpretative and poetic processes, develops the argument for incorporating the Huarte House into the experimental category. The thesis addresses the characteristic concepts of a house, from the general to the more specific, divided in four groups: composition, volume and space; the patio: architecture and landscape; the garden: building the horizon and eurythmy: spirit and matter. Molezún was convinced that to get to know a work of architecture it was necessary to draw it. The Huarte House is redrawn in its three main phases: the executive project (march 1965), the finished house (november 1966) and its actual state (2012). The study and analysis centers on the built house, as the actual tri-dimensional manifestation of the project. The graphic documentation of the present state of the house has never been published before and has been made possible by numerous visits to the House facilitated by Jesus Huarte’s daughters who are the current owners. This documentation allows us to determine any alterations of the constructed work and derive the necessary modifications to bring the house back to its original state. The Huarte House is a unique work, one of five single family homes registered by the International Docomomo. Its future is uncertain. It is currently uninhabited and up for sale. The Huarte family has more than delivered on the mission to safeguard its patrimony. It is important to defend its place as a key work of Spanish architecture of the 20th century and so avoid it being forgotten and abandoned.

Modelización y validación experimental del transporte de tritio en metal líquido y otros materiales para reactores de fusión nuclear magnética e inercial

La presente tesis se centra en el estudio de los fenómenos de transporte de los isótopos de hidrógeno, y más concretamente del tritio, en materiales de interés para los reactores de fusión nuclear. Los futuros reactores de fusión nuclear necesitarán una Planta de Tritio, con una envoltura regeneradora (breeding blanket) y unos sistemas auxiliares claves para su diseño. Por lo tanto su desarrollo y cualificación son cruciales para demostrar que los reactores de fusión son una opción viable como futura fuente de energía. Se han resaltado los diferentes retos de la difusión y retención de estas especies ligeras para cada sistema de la Planta de Tritio, y se han identificado las necesidades experimentales y paramétricas para abordar las simulaciones de difusión, como factores de transporte como la difusividad, absorción/desorción, solubilidad y atrapamiento. Se han estudiado los fenómenos de transporte y parámetros del T en el metal líquido LiPb, componente del breeding blanket tanto para una planta de fusión magnética como inercial. Para ello se han utilizado dos experimentos con características diversas, uno de ellos se ha llevado a cabo en un reactor de alto flujo, y por lo tanto, en condiciones de irradiación, y el otro sin irradiación. Los métodos de simulación numérica aplicados se han adaptado a los experimentos para las mediciones y para estudiar el régimen de transporte. En el estudio de estos experimentos se ha obtenido un valor para algunos de los parámetros claves en el transporte y gestión del tritio en el reactor. Finalmente se realiza un cálculo de la acumulación y difusión de tritio en una primera pared de tungsteno para un reactor de fusión inercial. En concreto para el proyecto de fusión por láser europeo, HiPER (para sus fases 4a y 4b). Se ha estudiado: la implantación de los isótopos de H y He en la pared de W tras una reacción de fusión por iluminación directa con un láser de 48MJ; el efecto en el transporte de T de los picos de temperatura en el W debido a la frecuencia de los eventos de fusión; el régimen de transporte en la primera pared. Se han identificado la naturaleza de las trampas más importantes para el T y se ha propuesto un modelo avanzado para la difusión con trampas. ABSTRACT The present thesis focuses into study the transport phenomenons of hydrogen isotopes, more specifically tritium, in materials of interest for nuclear fusion reactors. The future nuclear reactors will be provided of a Tritium Plant, with its breeding blanket and its auxiliary systems, all of them essential components for the plant. Therefore a reliable development and coalification are key issues to prove the viability of the nuclear fusion reactors as an energy source. The currently challenges for the diffusion and accumulation of these light species for each system of the TP has been studied. Experimental and theoretical needs have been identified and analyzed, specially from the viewpoint of the parameters. To achieve reliable simulations of tritium transport, parameters as diffusivity, absorption/desorption, solubility and trapping must be reliables. Transport phenomenon and parameters of T in liquid metal have been studied. Lead lithium is a key component of the breeding blanket, either in magnetic or inertial fusion confinement. Having this aim in mind, two experiments with different characteristics have been used; one of them has been realized in a high flux reactor, and hence, under irradiation conditions. The other one has been realized without radiation. The mathematical methods for the simulation have been adapted to the experiments, for the measures and also to study the transport behavior. A value for some key parameters for tritium management has been obtained in these studies. Finally, tritium accumulation and diffusion in a W first wall of an inertial nuclear fusion reactor has been assessed. A diffusion model of the implanted H, D, T and He species for the two initial phases of the proposed European laser fusion Project HiPER (namely, phase 4a and phase 4b) has been implemented using Tritium Migration Analysis Program, TMAP7. The effect of the prompt and working temperatures and the operational pulsing modes on the diffusion are studied. The nature of tritium traps in W and their performance has been analyzed and discussed.

Tritium permeation experiment at IFMIF Medium Flux Test Module

Tritium release experiments using different breeding material candidates are planned for the medium flux region of the IFMIF Test Cell. Nowadays, only ceramic breeder materials have been suggested to be tested in the Tritium Release Module located in the Medium Flux Test Module of IFMIF. Liquid breeder blankets are very promising and for that reason, several concepts will be tested in ITER. One of the main problems concerning the liquid blankets is the permeation of the generated tritium in the breeder throughout the walls. Since tritium permeation is highly influenced by irradiation conditions, IFMIF is a suitable scenario to perform tritium permeation related experiments. In this paper, a preliminary design of a tritium permeation experiment for the Medium Flux Test Module of IFMIF is proposed, in order to contribute to the progress of the liquid breeder blanket concept validation. The conceptual design of the capsule in which the experiment will be performed is carried out, taking into consideration the experiment necessities and its implementation in the Tritium Release Module. In addition to this, some thermal hydraulic calculations have been performed to evaluate the thermal behaviour of the irradiation capsule

Present status of the Liquid Breeder Validation

One of the objectives of IFMIF (International Fusion Materials Irradiation Facility), as stated in its specifications, is the validation of breeder blanket concepts for DEMO design. The so-called Liquid Breeder Validation Module (LBVM) will be used in IFMIF to perform experiments under irradiation on functional materials related to liquid breeder concepts for future fusion reactors. This module, not considered in previous IFMIF design phases, is currently under design by CIEMAT in the framework of the IFMIF/EVEDA project. In this paper, the present status of the design of the LBVM is presented.

Diseño de un módulo de IFMIF para irradiación de envolturas regeneradoras basadas en metales líquidos para reactores de fusión

La fusión nuclear es, hoy en día, una alternativa energética a la que la comunidad internacional dedica mucho esfuerzo. El objetivo es el de generar entre diez y cincuenta veces más energía que la que consume mediante reacciones de fusión que se producirán en una mezcla de deuterio (D) y tritio (T) en forma de plasma a doscientos millones de grados centígrados. En los futuros reactores nucleares de fusión será necesario producir el tritio utilizado como combustible en el propio reactor termonuclear. Este hecho supone dar un paso más que las actuales máquinas experimentales dedicadas fundamentalmente al estudio de la física del plasma. Así pues, el tritio, en un reactor de fusión, se produce en sus envolturas regeneradoras cuya misión fundamental es la de blindaje neutrónico, producir y recuperar tritio (fuel para la reacción DT del plasma) y por último convertir la energía de los neutrones en calor. Existen diferentes conceptos de envolturas que pueden ser sólidas o líquidas. Las primeras se basan en cerámicas de litio (Li2O, Li4SiO4, Li2TiO3, Li2ZrO3) y multiplicadores neutrónicos de Be, necesarios para conseguir la cantidad adecuada de tritio. Los segundos se basan en el uso de metales líquidos o sales fundidas (Li, LiPb, FLIBE, FLINABE) con multiplicadores neutrónicos de Be o el propio Pb en el caso de LiPb. Los materiales estructurales pasan por aceros ferrítico-martensíticos de baja activación, aleaciones de vanadio o incluso SiCf/SiC. Cada uno de los diferentes conceptos de envoltura tendrá una problemática asociada que se estudiará en el reactor experimental ITER (del inglés, “International Thermonuclear Experimental Reactor”). Sin embargo, ITER no puede responder las cuestiones asociadas al daño de materiales y el efecto de la radiación neutrónica en las diferentes funciones de las envolturas regeneradoras. Como referencia, la primera pared de un reactor de fusión de 4000MW recibiría 30 dpa/año (valores para Fe-56) mientras que en ITER se conseguirían <10 dpa en toda su vida útil. Esta tesis se encuadra en el acuerdo bilateral entre Europa y Japón denominado “Broader Approach Agreement “(BA) (2007-2017) en el cual España juega un papel destacable. Estos proyectos, complementarios con ITER, son el acelerador para pruebas de materiales IFMIF (del inglés, “International Fusion Materials Irradiation Facility”) y el dispositivo de fusión JT-60SA. Así, los efectos de la irradiación de materiales en materiales candidatos para reactores de fusión se estudiarán en IFMIF. El objetivo de esta tesis es el diseño de un módulo de IFMIF para irradiación de envolturas regeneradoras basadas en metales líquidos para reactores de fusión. El módulo se llamará LBVM (del inglés, “Liquid Breeder Validation Module”). La propuesta surge de la necesidad de irradiar materiales funcionales para envolturas regeneradoras líquidas para reactores de fusión debido a que el diseño conceptual de IFMIF no contaba con esta utilidad. Con objeto de analizar la viabilidad de la presente propuesta, se han realizado cálculos neutrónicos para evaluar la idoneidad de llevar a cabo experimentos relacionados con envolturas líquidas en IFMIF. Así, se han considerado diferentes candidatos a materiales funcionales de envolturas regeneradoras: Fe (base de los materiales estructurales), SiC (material candidato para los FCI´s (del inglés, “Flow Channel Inserts”) en una envoltura regeneradora líquida, SiO2 (candidato para recubrimientos antipermeación), CaO (candidato para recubrimientos aislantes), Al2O3 (candidato para recubrimientos antipermeación y aislantes) y AlN (material candidato para recubrimientos aislantes). En cada uno de estos materiales se han calculado los parámetros de irradiación más significativos (dpa, H/dpa y He/dpa) en diferentes posiciones de IFMIF. Estos valores se han comparado con los esperados en la primera pared y en la zona regeneradora de tritio de un reactor de fusión. Para ello se ha elegido un reactor tipo HCLL (del inglés, “Helium Cooled Lithium Lead”) por tratarse de uno de los más prometedores. Además, los valores también se han comparado con los que se obtendrían en un reactor rápido de fisión puesto que la mayoría de las irradiaciones actuales se hacen en reactores de este tipo. Como conclusión al análisis de viabilidad, se puede decir que los materiales funcionales para mantos regeneradores líquidos podrían probarse en la zona de medio flujo de IFMIF donde se obtendrían ratios de H/dpa y He/dpa muy parecidos a los esperados en las zonas más irradiadas de un reactor de fusión. Además, con el objetivo de ajustar todavía más los valores, se propone el uso de un moderador de W (a considerar en algunas campañas de irradiación solamente debido a que su uso hace que los valores de dpa totales disminuyan). Los valores obtenidos para un reactor de fisión refuerzan la idea de la necesidad del LBVM, ya que los valores obtenidos de H/dpa y He/dpa son muy inferiores a los esperados en fusión y, por lo tanto, no representativos. Una vez demostrada la idoneidad de IFMIF para irradiar envolturas regeneradoras líquidas, y del estudio de la problemática asociada a las envolturas líquidas, también incluida en esta tesis, se proponen tres tipos de experimentos diferentes como base de diseño del LBVM. Éstos se orientan en las necesidades de un reactor tipo HCLL aunque a lo largo de la tesis se discute la aplicabilidad para otros reactores e incluso se proponen experimentos adicionales. Así, la capacidad experimental del módulo estaría centrada en el estudio del comportamiento de litio plomo, permeación de tritio, corrosión y compatibilidad de materiales. Para cada uno de los experimentos se propone un esquema experimental, se definen las condiciones necesarias en el módulo y la instrumentación requerida para controlar y diagnosticar las cápsulas experimentales. Para llevar a cabo los experimentos propuestos se propone el LBVM, ubicado en la zona de medio flujo de IFMIF, en su celda caliente, y con capacidad para 16 cápsulas experimentales. Cada cápsula (24-22 mm de diámetro y 80 mm de altura) contendrá la aleación eutéctica LiPb (hasta 50 mm de la altura de la cápsula) en contacto con diferentes muestras de materiales. Ésta irá soportada en el interior de tubos de acero por los que circulará un gas de purga (He), necesario para arrastrar el tritio generado en el eutéctico y permeado a través de las paredes de las cápsulas (continuamente, durante irradiación). Estos tubos, a su vez, se instalarán en una carcasa también de acero que proporcionará soporte y refrigeración tanto a los tubos como a sus cápsulas experimentales interiores. El módulo, en su conjunto, permitirá la extracción de las señales experimentales y el gas de purga. Así, a través de la estación de medida de tritio y el sistema de control, se obtendrán los datos experimentales para su análisis y extracción de conclusiones experimentales. Además del análisis de datos experimentales, algunas de estas señales tendrán una función de seguridad y por tanto jugarán un papel primordial en la operación del módulo. Para el correcto funcionamiento de las cápsulas y poder controlar su temperatura, cada cápsula se equipará con un calentador eléctrico y por tanto el módulo requerirá también ser conectado a la alimentación eléctrica. El diseño del módulo y su lógica de operación se describe en detalle en esta tesis. La justificación técnica de cada una de las partes que componen el módulo se ha realizado con soporte de cálculos de transporte de tritio, termohidráulicos y mecánicos. Una de las principales conclusiones de los cálculos de transporte de tritio es que es perfectamente viable medir el tritio permeado en las cápsulas mediante cámaras de ionización y contadores proporcionales comerciales, con sensibilidades en el orden de 10-9 Bq/m3. Los resultados son aplicables a todos los experimentos, incluso si son cápsulas a bajas temperaturas o si llevan recubrimientos antipermeación. Desde un punto de vista de seguridad, el conocimiento de la cantidad de tritio que está siendo transportada con el gas de purga puede ser usado para detectar de ciertos problemas que puedan estar sucediendo en el módulo como por ejemplo, la rotura de una cápsula. Además, es necesario conocer el balance de tritio de la instalación. Las pérdidas esperadas el refrigerante y la celda caliente de IFMIF se pueden considerar despreciables para condiciones normales de funcionamiento. Los cálculos termohidráulicos se han realizado con el objetivo de optimizar el diseño de las cápsulas experimentales y el LBVM de manera que se pueda cumplir el principal requisito del módulo que es llevar a cabo los experimentos a temperaturas comprendidas entre 300-550ºC. Para ello, se ha dimensionado la refrigeración necesaria del módulo y evaluado la geometría de las cápsulas, tubos experimentales y la zona experimental del contenedor. Como consecuencia de los análisis realizados, se han elegido cápsulas y tubos cilíndricos instalados en compartimentos cilíndricos debido a su buen comportamiento mecánico (las tensiones debidas a la presión de los fluidos se ven reducidas significativamente con una geometría cilíndrica en lugar de prismática) y térmico (uniformidad de temperatura en las paredes de los tubos y cápsulas). Se han obtenido campos de presión, temperatura y velocidad en diferentes zonas críticas del módulo concluyendo que la presente propuesta es factible. Cabe destacar que el uso de códigos fluidodinámicos (e.g. ANSYS-CFX, utilizado en esta tesis) para el diseño de cápsulas experimentales de IFMIF no es directo. La razón de ello es que los modelos de turbulencia tienden a subestimar la temperatura de pared en mini canales de helio sometidos a altos flujos de calor debido al cambio de las propiedades del fluido cerca de la pared. Los diferentes modelos de turbulencia presentes en dicho código han tenido que ser estudiados con detalle y validados con resultados experimentales. El modelo SST (del inglés, “Shear Stress Transport Model”) para turbulencia en transición ha sido identificado como adecuado para simular el comportamiento del helio de refrigeración y la temperatura en las paredes de las cápsulas experimentales. Con la geometría propuesta y los valores principales de refrigeración y purga definidos, se ha analizado el comportamiento mecánico de cada uno de los tubos experimentales que contendrá el módulo. Los resultados de tensiones obtenidos, han sido comparados con los valores máximos recomendados en códigos de diseño estructural como el SDC-IC (del inglés, “Structural Design Criteria for ITER Components”) para así evaluar el grado de protección contra el colapso plástico. La conclusión del estudio muestra que la propuesta es mecánicamente robusta. El LBVM implica el uso de metales líquidos y la generación de tritio además del riesgo asociado a la activación neutrónica. Por ello, se han estudiado los riesgos asociados al uso de metales líquidos y el tritio. Además, se ha incluido una evaluación preliminar de los riesgos radiológicos asociados a la activación de materiales y el calor residual en el módulo después de la irradiación así como un escenario de pérdida de refrigerante. Los riesgos asociados al módulo de naturaleza convencional están asociados al manejo de metales líquidos cuyas reacciones con aire o agua se asocian con emisión de aerosoles y probabilidad de fuego. De entre los riesgos nucleares destacan la generación de gases radiactivos como el tritio u otros radioisótopos volátiles como el Po-210. No se espera que el módulo suponga un impacto medioambiental asociado a posibles escapes. Sin embargo, es necesario un manejo adecuado tanto de las cápsulas experimentales como del módulo contenedor así como de las líneas de purga durante operación. Después de un día de después de la parada, tras un año de irradiación, tendremos una dosis de contacto de 7000 Sv/h en la zona experimental del contenedor, 2300 Sv/h en la cápsula y 25 Sv/h en el LiPb. El uso por lo tanto de manipulación remota está previsto para el manejo del módulo irradiado. Por último, en esta tesis se ha estudiado también las posibilidades existentes para la fabricación del módulo. De entre las técnicas propuestas, destacan la electroerosión, soldaduras por haz de electrones o por soldadura láser. Las bases para el diseño final del LBVM han sido pues establecidas en el marco de este trabajo y han sido incluidas en el diseño intermedio de IFMIF, que será desarrollado en el futuro, como parte del diseño final de la instalación IFMIF. ABSTRACT Nuclear fusion is, today, an alternative energy source to which the international community devotes a great effort. The goal is to generate 10 to 50 times more energy than the input power by means of fusion reactions that occur in deuterium (D) and tritium (T) plasma at two hundred million degrees Celsius. In the future commercial reactors it will be necessary to breed the tritium used as fuel in situ, by the reactor itself. This constitutes a step further from current experimental machines dedicated mainly to the study of the plasma physics. Therefore, tritium, in fusion reactors, will be produced in the so-called breeder blankets whose primary mission is to provide neutron shielding, produce and recover tritium and convert the neutron energy into heat. There are different concepts of breeding blankets that can be separated into two main categories: solids or liquids. The former are based on ceramics containing lithium as Li2O , Li4SiO4 , Li2TiO3 , Li2ZrO3 and Be, used as a neutron multiplier, required to achieve the required amount of tritium. The liquid concepts are based on molten salts or liquid metals as pure Li, LiPb, FLIBE or FLINABE. These blankets use, as neutron multipliers, Be or Pb (in the case of the concepts based on LiPb). Proposed structural materials comprise various options, always with low activation characteristics, as low activation ferritic-martensitic steels, vanadium alloys or even SiCf/SiC. Each concept of breeding blanket has specific challenges that will be studied in the experimental reactor ITER (International Thermonuclear Experimental Reactor). However, ITER cannot answer questions associated to material damage and the effect of neutron radiation in the different breeding blankets functions and performance. As a reference, the first wall of a fusion reactor of 4000 MW will receive about 30 dpa / year (values for Fe-56) , while values expected in ITER would be <10 dpa in its entire lifetime. Consequently, the irradiation effects on candidate materials for fusion reactors will be studied in IFMIF (International Fusion Material Irradiation Facility). This thesis fits in the framework of the bilateral agreement among Europe and Japan which is called “Broader Approach Agreement “(BA) (2007-2017) where Spain plays a key role. These projects, complementary to ITER, are mainly IFMIF and the fusion facility JT-60SA. The purpose of this thesis is the design of an irradiation module to test candidate materials for breeding blankets in IFMIF, the so-called Liquid Breeder Validation Module (LBVM). This proposal is born from the fact that this option was not considered in the conceptual design of the facility. As a first step, in order to study the feasibility of this proposal, neutronic calculations have been performed to estimate irradiation parameters in different materials foreseen for liquid breeding blankets. Various functional materials were considered: Fe (base of structural materials), SiC (candidate material for flow channel inserts, SiO2 (candidate for antipermeation coatings), CaO (candidate for insulating coatings), Al2O3 (candidate for antipermeation and insulating coatings) and AlN (candidate for insulation coating material). For each material, the most significant irradiation parameters have been calculated (dpa, H/dpa and He/dpa) in different positions of IFMIF. These values were compared to those expected in the first wall and breeding zone of a fusion reactor. For this exercise, a HCLL (Helium Cooled Lithium Lead) type was selected as it is one of the most promising options. In addition, estimated values were also compared with those obtained in a fast fission reactor since most of existing irradiations have been made in these installations. The main conclusion of this study is that the medium flux area of IFMIF offers a good irradiation environment to irradiate functional materials for liquid breeding blankets. The obtained ratios of H/dpa and He/dpa are very similar to those expected in the most irradiated areas of a fusion reactor. Moreover, with the aim of bringing the values further close, the use of a W moderator is proposed to be used only in some experimental campaigns (as obviously, the total amount of dpa decreases). The values of ratios obtained for a fission reactor, much lower than in a fusion reactor, reinforce the need of LBVM for IFMIF. Having demonstrated the suitability of IFMIF to irradiate functional materials for liquid breeding blankets, and an analysis of the main problems associated to each type of liquid breeding blanket, also presented in this thesis, three different experiments are proposed as basis for the design of the LBVM. These experiments are dedicated to the needs of a blanket HCLL type although the applicability of the module for other blankets is also discussed. Therefore, the experimental capability of the module is focused on the study of the behavior of the eutectic alloy LiPb, tritium permeation, corrosion and material compatibility. For each of the experiments proposed an experimental scheme is given explaining the different module conditions and defining the required instrumentation to control and monitor the experimental capsules. In order to carry out the proposed experiments, the LBVM is proposed, located in the medium flux area of the IFMIF hot cell, with capability of up to 16 experimental capsules. Each capsule (24-22 mm of diameter, 80 mm high) will contain the eutectic allow LiPb (up to 50 mm of capsule high) in contact with different material specimens. They will be supported inside rigs or steel pipes. Helium will be used as purge gas, to sweep the tritium generated in the eutectic and permeated through the capsule walls (continuously, during irradiation). These tubes, will be installed in a steel container providing support and cooling for the tubes and hence the inner experimental capsules. The experimental data will consist of on line monitoring signals and the analysis of purge gas by the tritium measurement station. In addition to the experimental signals, the module will produce signals having a safety function and therefore playing a major role in the operation of the module. For an adequate operation of the capsules and to control its temperature, each capsule will be equipped with an electrical heater so the module will to be connected to an electrical power supply. The technical justification behind the dimensioning of each of these parts forming the module is presented supported by tritium transport calculations, thermalhydraulic and structural analysis. One of the main conclusions of the tritium transport calculations is that the measure of the permeated tritium is perfectly achievable by commercial ionization chambers and proportional counters with sensitivity of 10-9 Bq/m3. The results are applicable to all experiments, even to low temperature capsules or to the ones using antipermeation coatings. From a safety point of view, the knowledge of the amount of tritium being swept by the purge gas is a clear indicator of certain problems that may be occurring in the module such a capsule rupture. In addition, the tritium balance in the installation should be known. Losses of purge gas permeated into the refrigerant and the hot cell itself through the container have been assessed concluding that they are negligible for normal operation. Thermal hydraulic calculations were performed in order to optimize the design of experimental capsules and LBVM to fulfill one of the main requirements of the module: to perform experiments at uniform temperatures between 300-550ºC. The necessary cooling of the module and the geometry of the capsules, rigs and testing area of the container were dimensioned. As a result of the analyses, cylindrical capsules and rigs in cylindrical compartments were selected because of their good mechanical behavior (stresses due to fluid pressure are reduced significantly with a cylindrical shape rather than prismatic) and thermal (temperature uniformity in the walls of the tubes and capsules). Fields of pressure, temperature and velocity in different critical areas of the module were obtained concluding that the proposal is feasible. It is important to mention that the use of fluid dynamic codes as ANSYS-CFX (used in this thesis) for designing experimental capsules for IFMIF is not direct. The reason for this is that, under strongly heated helium mini channels, turbulence models tend to underestimate the wall temperature because of the change of helium properties near the wall. Therefore, the different code turbulence models had to be studied in detail and validated against experimental results. ANSYS-CFX SST (Shear Stress Transport Model) for transitional turbulence model has been identified among many others as the suitable one for modeling the cooling helium and the temperature on the walls of experimental capsules. Once the geometry and the main purge and cooling parameters have been defined, the mechanical behavior of each experimental tube or rig including capsules is analyzed. Resulting stresses are compared with the maximum values recommended by applicable structural design codes such as the SDC- IC (Structural Design Criteria for ITER Components) in order to assess the degree of protection against plastic collapse. The conclusion shows that the proposal is mechanically robust. The LBVM involves the use of liquid metals, tritium and the risk associated with neutron activation. The risks related with the handling of liquid metals and tritium are studied in this thesis. In addition, the radiological risks associated with the activation of materials in the module and the residual heat after irradiation are evaluated, including a scenario of loss of coolant. Among the identified conventional risks associated with the module highlights the handling of liquid metals which reactions with water or air are accompanied by the emission of aerosols and fire probability. Regarding the nuclear risks, the generation of radioactive gases such as tritium or volatile radioisotopes such as Po-210 is the main hazard to be considered. An environmental impact associated to possible releases is not expected. Nevertheless, an appropriate handling of capsules, experimental tubes, and container including purge lines is required. After one day after shutdown and one year of irradiation, the experimental area of the module will present a contact dose rate of about 7000 Sv/h, 2300 Sv/h in the experimental capsules and 25 Sv/h in the LiPb. Therefore, the use of remote handling is envisaged for the irradiated module. Finally, the different possibilities for the module manufacturing have been studied. Among the proposed techniques highlights the electro discharge machining, brazing, electron beam welding or laser welding. The bases for the final design of the LBVM have been included in the framework of the this work and included in the intermediate design report of IFMIF which will be developed in future, as part of the IFMIF facility final design.

Avaliação do antagonismo do efeito do sódio sobre o tratamento de água residuária de Charqueada com elevada salinidade em reator anaeróbio de manta de lodo (UASB)

As águas residuárias provenientes da indústria do charque são conhecidas por apresentarem elevado teor de cloreto de sódio, aliado a grandes concentrações de matéria orgânica proveniente do sangue liberado ao longo do processo industrial. Esse tipo de água residuária apresenta potencial para degradação biológica, contudo, o cloreto de sódio, em concentração elevada, pode inibir a atividade dos microrganismos e, em alguns casos, levar sistemas biológicos à falência. No presente trabalho, foi avaliada a viabilidade de degradação anaeróbia de efluente sintético de Charqueada contendo elevado teor de cloreto de sódio, em reator anaeróbio tipo UASB (Upflow Anaerobic Sludge Blanket), em escala de laboratório. Foram utilizados 4 reatores, alimentados com água residuária sintética com características similares à água residuária de Charqueada. O reator 1 foi utilizado como controle, o reator 2 recebeu NaCl e os demais (3 e 4) foram operados na presença de NaCl acrescidos de: betaína e potássio com cálcio, respectivamente. Os compostos citados são conhecidos como antagonizantes, por possuirem capacidade de minimizar o efeito inibitório do sódio sobre o processo de digestão anaeróbia. Os reatores foram inoculados com lodo de reator UASB e submetidos à concentração de 5000 mg/L de matéria orgânica, como DQO. A carga orgânica aplicada foi de 5 Kg/m3.d e os reatores não suportaram tal carga. Reiniciou-se a operação com aumento progressivo da DQO de 500 a 2000 mg/L resultando em cargas orgânicas de 0,5 a 2,0 Kg/m3.d, respectivamente. Após estabilização dos reatores, iniciou-se a fase de introdução de cloreto de sódio (1.500 a 13.500 mg/L) e antagonizantes com aumento progressivo a cada fase. Na presença ou ausência de antagonizantes, os reatores 2, 3 e 4 não tiveram o desempenho alterado até a concentração de NaCl de 6000 mg/L. Na presença de 9000 mg/L de NaCl, a betaína se mostrou pouco efetiva como soluto compatível no reator 3 e os antagonizantes do reator 4, potássio e cálcio, apresentaram efeitos estimulatórios. As morfologias encontradas ao longo do experimento foram cocos, víbrios, bacilos, sarcinas, além de morfologias semelhantes a Methanosarcina sp. e Methanosaeta sp. O aumento da concentração de cloreto de sódio provocou a redição da população de Arqueas.

Pós-tratamento físico-químico por flotação de efluentes de reatores anaeróbios de manta de lodo (UASB)

O emprego da flotação por ar dissolvido (FAD) para o pós-tratamento de efluentes de reatores anaeróbios aparenta ser atraente considerando algumas características desse processo físico-químico. A FAD é reconhecidamente um processo de alta taxa, particularmente eficiente na remoção de material particulado em suspensão e de flocos produzidos pela coagulação química de águas residuárias. Além disso, há produção de lodo espesso e provavelmente arraste de parcela de gases e de compostos voláteis, presentes nos efluentes anaeróbios. Entretanto, a concepção de sistemas de FAD deve ser precedida por ensaios em unidades de flotação em escala de laboratório, permitindo a determinação dos principais parâmetros do processo. Neste trabalho, são apresentados e discutidos os resultados obtidos em laboratório e em instalação piloto de flotação com escoamento contínuo recebendo efluente de reator anaeróbio de manta de lodo (UASB), com 18 m3 de volume, tratando esgoto sanitário. Os ensaios em unidade em escala de laboratório foram realizados utilizando diferentes dosagens de cloreto férrico (entre 30 e 110 mg/L) ou de polímero catiônico (entre 1,0 e 16,0 mg/L), atuando como coagulantes. Além disso, foram estudadas as condições de floculação (tempo de 15 e de 25 min, e gradiente médio de velocidade de floculação entre 30 e 100 s-1) e diferentes valores de quantidade de ar fornecido ao processo (S*, entre 4,7 e 28,5 g de ar por m3 de efluente). Com a instalação piloto de FAD foram realizados apenas ensaios preliminares variando-se a taxa de aplicação superficial (140 e 210 m3/m2/d) para diferentes valores de S* (14,8 a 29,5 g de ar por m3 de efluente). Com o emprego de dosagem de 65 mg/L de cloreto férrico, de tempo de 15 min e gradiente médio de velocidade de floculação de 80 s-1 e de 19 g de ar por m3 de efluente, foram observados excelentes resultados em laboratório, com elevadas remoções de DQO (89%), de fosfato total (96%), de sólidos suspensos totais (96%), de turbidez (98%), de cor aparente (91%), de sulfetos (não detectado) e NTK (47%). Considerando o sistema UASB e FAD, nos testes em laboratório, foram observadas remoções globais de 97,7% de DQO, de 98,0% de fosfato total, de 98,9% de SST, de 99,5% de turbidez, de 97,8% de cor aparente e de 59,0% de NTK. Nos ensaios com a instalação piloto de FAD, o sistema apresentou remoções de 93,6% de DQO, de 87,1% de SST, de 90% de sulfetos e de 30% de NTK.

Framing Banking Union in the Euro Area: Some empirical evidence. CEPS Working Document No. 389, 3 February 2014

Evidence shows that financial integration in the euro area is retrenching at a quicker pace than outside the union. Home bias persists: Governments compete on funding costs by supporting ‘their’ banks with massive state aids, which distorts the playing field and feeds the risk-aversion loop. This situation intensifies friction in credit markets, thus hampering the transmission of monetary policies and, potentially, economic growth. This paper discusses the theoretical foundations of a banking union in a common currency area and the legal and economic aspects of EU responses. As a result, two remedies are proposed to deal with moral hazard in a common currency area: a common (unlimited) financial backstop to a privately funded recapitalisation/resolution fund and a blanket prohibition on state aids.

Building International CSR on Solid Foundations: Location and Network Aspects of Nonmarket Environments in Europe and Non-Europe Markets. ACES Working Papers, 2011

Multinational companies' (MNCs) corporate social responsibility (CSR) programs frequently comprise a portfolio of disconnected country-level programs or, alternatively, consist of blanket corporate policies that apply in the same way across the geographies where the company operates. Yet, the international nonmarket environment in which CSR programs operate is neither a completely fragmented nor a perfectly homogeneous one. Building on the concept of stakeholder-issue-networks, we develop a model that explicitly takes into consideration the role of geography in the characterization of a firm's nonmarket environment. This allows us to develop a taxonomy of nonmarket environments on the basis of their geographic spread and their degree of cross-border connectedness. We then explore the strategic and organizational implications that different ideal types of (cross-border) nonmarket environments have for the development of international CSR policies.

To be in, or to be out: reflections on the Danish referendum. EPIN Commentary No. 29, 10 December 2015

In this EPIN Commentary, Catharina Sørensen offers her reflections on Denmark’s referendum, held on December 3rd, on whether the country should change its blanket opt-out on all justice and home affairs cooperation in the EU to the more nuanced opt-in model adopted by the UK and Ireland. In her view, the outcome reflected the two separate ‘languages’ deployed in the public debate over the referendum – the emotional discussion about sovereignty, which appealed to the heart, and the technical argument about cooperation, which appealed to reason. In using these two languages, the campaigners spoke past one another, failed to understand each other and divided Denmark into two opposing camps.

Description of the ITER Tokamak Cooling Water System

In questa tesi ho inizialmente esposto cenni teorici sulle reazioni di fusione nucleare e le motivazioni che hanno spinto la comunità scientifica verso la ricerca di questa nuova fonte energetica. Ho descritto il progetto ITER nei suoi obiettivi e nei principi di funzionamento di un reattore di tipo Tokamak e di tutti i componenti principali dell'intero impianto. In primo piano, mi sono focalizzato sul sistema di raffreddamento primario ad acqua del Tokamak (TCWS), con una prima panoramica sui suoi sottosistemi descrivendo i loro obiettivi, quali asportazione di calore e sicurezza dell'impianto. Successivamente ho analizzato nello specifico i particolari tecnici dei principali sottosistemi quali i vari circuiti di asportazione primaria del calore (PHTS Loops) dei diversi componenti del Tokamak, il Vacuum Vessel, il First Wall Blanket, il Divertor e il Neutral Beam Injector; ho esaminato i processi di controllo della qualità e del volume del fluido refrigerante nei circuiti (CVCS); ed infine le funzioni e le caratteristiche dei sistemi di drenaggio e di riempimento dei circuiti con i propri serbatoi ordinari e di sicurezza, e del sistema di asciugatura del fluido refrigerante con le sue diverse modalità operative.

Ecosystem structure, function, and composition in rangelands are negatively affected by livestock grazing

Reports of positive or neutral effects of grazing on plant species richness have prompted calls for livestock grazing to be used as a tool for managing land for conservation. Grazing effects, however, are likely to vary among different response variables, types, and intensity of grazing, and across abiotic conditions. We aimed to examine how grazing affects ecosystem structure, function, and composition. We compiled a database of 7615 records reporting an effect of grazing by sheep and cattle on 278 biotic and abiotic response variables for published studies across Australia. Using these data, we derived three ecosystem measures based on structure, function, and composition, which were compared against six contrasts of grazing pressure, ranging from low to heavy, two different herbivores (sheep, cattle), and across three different climatic zones. Grazing reduced structure (by 35%), function (24%), and composition (10%). Structure and function (but not composition) declined more when grazed by sheep and cattle together than sheep alone. Grazing reduced plant biomass (40%), animal richness (15%), and plant and animal abundance, and plant and litter cover (25%), but had no effect on plant richness nor soil function. The negative effects of grazing on plant biomass, plant cover, and soil function were more pronounced in drier environments. Grazing effects on plant and animal richness and composition were constant, or even declined, with increasing aridity. Our study represents a comprehensive continental assessment of the implications of grazing for managing Australian rangelands. Grazing effects were largely negative, even at very low levels of grazing. Overall, our results suggest that livestock grazing in Australia is unlikely to produce positive outcomes for ecosystem structure, function, and composition or even as a blanket conservation tool unless reduction in specific response variables is an explicit management objective.

Fielding Yost, ca. 1940

[Yost with blanket presented by 1940 football captain Forest Evashevski to "Great Scalper Yost" on behalf of Michigamua]

The influence of substrate kinetics on the microbial community structure in granular anaerobic biomass

The development of a strong, active granular sludge bed is necessary for optimal operation of upflow anaerobic sludge blanket reactors. The microbial and mechanical structure of the granules may have a strong influence on desirable properties such as growth rate, settling velocity and shear strength. Theories have been proposed for granule microbial structure based on the relative kinetics of substrate degradation, but contradict some observations from both modelling and microscopic studies. In this paper, the structures of four granule types were examined from full-scale UASB reactors, treating wastewater from a cannery, a slaughterhouse, and two breweries. Microbial structure was determined using fluorescence in situ hybridisation probing with 16S rRNA-directed oligonucleotide probes, and superficial structure and microbial density (volume occupied by cells and microbial debris) assessed using scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The granules were also modelled using a distributed parameter biofilm model, with a previously published biochemical model structure, biofilm modelling approach, and model parameters. The model results reflected the trophic structures observed, indicating that the structures were possibly determined by kinetics. Of particular interest were results from simulations of the protein grown granules, which were predicted to have slow growth rates, low microbial density, and no trophic layers, the last two of which were reflected by microscopic observations. The primary cause of this structure, as assessed by modelling, was the particulate nature of the wastewater, and the slow rate of particulate hydrolysis, rather than the presence of proteins in the wastewater. Because solids hydrolysis was rate limiting, soluble substrate concentrations were very low (below Monod half saturation concentration), which caused low growth rates. (C) 2003 Elsevier Ltd. All rights reserved.

The availability of nitrogen from sugarcane trash on contrasting soils in the wet tropics of North Queensland

Sugarcane crop residues ('trash') have the potential to supply nitrogen (N) to crops when they are retained on the soil surface after harvest. Farmers should account for the contribution of this N to crop requirements in order to avoid over-fertilisation. In very wet tropical locations, the climate may increase the rate of trash decomposition as well as the amount of N lost from the soil-plant system due to leaching or denitrification. A field experiment was conducted on Hydrosol and Ferrosol soils in the wet tropics of northern Australia using N-15-labelled trash either applied to the soil surface or incorporated. Labelled urea fertiliser was also applied with unlabelled surface trash. The objective of the experiment was to investigate the contribution of trash to crop N nutrition in wet tropical climates, the timing of N mineralisation from trash, and the retention of trash N in contrasting soils. Less than 6% of the N in trash was recovered in the first crop and the recovery was not affected by trash incorporation. Around 6% of the N in fertiliser was also recovered in the first crop, which was less than previously measured in temperate areas (20-40%). Leaf samples taken at the end of the second crop contined 2-3% of N from trash and fertilizer applied at the beginning of the experiment. Although most N was recovered in the 0-1.5 m soil layer there was some evidence of movement of N below this depth. The results showed that trash supplies N slowly and in small amounts to the succeeding crop in wet tropics sugarcane growing areas regardless of trash placement (on the soil surface or incorporated) or soil type, and so N mineralisation from a single trash blanket is not important for sugarcane production in the wet tropics.