Recursos de colección

Archivo Digital UPM (109.118 recursos)

This is an institutional repository providing access to the research output of the institution. Primarily contains thesis.

Materia = Energía Nuclear

Mostrando recursos 1 - 20 de 292

  1. Neutron detectors of 10B+ZnS(Ag) as an alternative to 3He-based installed in the Radiation Portal Monitors in homeland Security

    Guzmán-García, Karen Arlete; Gallego Díaz, Eduardo F.; Vega Carrillo, Héctor René; Lorente Fillol, Alfredo; González González, Juan Antonio
    Using Monte Carlo method features of 10B+ZnS(Ag) neutron detector under real operational conditions has been calculated, this results were compared against measurements. This detector is a viable substitute for 3He detectors installed in custom borders to prevent the illicit traffic of special nuclear materials, SNM.

  2. Obtención de la ecuación constitutiva de ampollas de hidruros mediante nanoindentación

    Ruiz Hervías, Jesús; Martín Rengel, Miguel Ángel; Gómez Sánchez, Francisco Javier; Rico García, Álvaro
    En el presente trabajo, se ha desarrollado un procedimiento experimental para generar ampollas de hidruros de circonio (“blisters”) en vainas de combustible nuclear. Dichas ampollas son similares a las encontradas en vainas irradiadas con hidruración severa. En una ampolla preparada en el laboratorio mediante esta técnica, se efectuaron ensayos de nanoindentación. Se desarrolló un modelo numérico, mediante el método de los elementos finitos, para ajustar las curvas cargapenetración de estos ensayos de nanoindentación. Por medio de un procedimiento inverso que combina resultados experimentales de nanoindentación y el modelo numérico, se determinó la ecuación constitutiva de las ampollas de hidruro.

  3. The Effect of Cr Concentration on Defect Energies in FeCr Alloys

    Rio Redondo, Emma del; Perlado Martín, José Manuel; Sampedro, Jesus M.; Caturla Terol, María José
    FeCr ferritic alloys are leading candidates for structural applications in generation IV fission reactors due to their high resistance to swelling and corrosion. The addition of Cr improves the behavior of the steels under irradiation, but this improvement is non-monotonic. Understandig the changes in the FeCr ferritic alloys microstructure induced by irradiation and the role played by the alloying element (Cr) is needed in order to predict the response of these materials under the extreme conditions in the future nuclear plants. In this work, we present the effect of Cr concentration in a bcc Fe matrix on binding and formation energies of vacancy...

  4. Capabilities of Nanostructured Tungsten for Plasma Facing Material

    Gonzalez Arrabal, Raquel; Gordillo Garcia, Nuria; Rivera Manso, Antonio Manuel; Panizo Laíz, Miguel; Valles Ruiz, Miguel; Gonzalez Bris, Carlos; Tejado Garrido, Elena Maria; Pastor Caño, Jose Ignacio; Perlado Martin, Jose Manuel; Balabanian, C.; Guerrero Contreras, Carlos Luis; Bringa, E.M.; Iglesias, R.; Inestrosa-Izurieta, M.J.; Munnik, F.; Martin-Bragado, I.; Molina, J.; Moreno, J.
    One of the bottle necks for fusion to become a reality is the lack of materials able to withstand the harsh conditions taken place in a reactor environment. In particular, plasma facing materials (PFM) have to resist large radiation fluxes and thermal loads. Nowadays, tungsten is one of the most attractive materials proposed for PFM. However, it is known that the irradiation of tungsten with H leads to surface blistering and subsequent cracking and exfoliation which is unacceptable. In particular, these effects have been observed to be more severe when W is subjected to pulse irradiation.

  5. Detectores de Neutrones de 10B+ZnS(Ag) como alternativa a los detectores de 3He instalados en los Monitores de Radiación tipo Pórtico RPM`s. Neutron Detectors 10B+ZnS(Ag) as an alternative to 3He-based installed in the Radiation Portal Monitors, RPM's

    Guzmán-García, Karen Arlete; Vega Carrillo, Héctor René; Gallego Díaz, Eduardo F.; González González, Juan Antonio; Lorente Fillol, Alfredo
    Los sistemas de detección llamados "Radiation Portal Monitors" RPMs o Monitores de Radiación tipo Pórtico habitualmente instalados en zonas fronterizas, son un conjunto de detectores gamma y de neutrones; el uso de detectores gamma se justifica para el control de presencia inadvertida de fuentes radiactivas y la colocación de detectores de neutrones para la detección de los llamados Material Nuclear Especial (SNM), como el 239Pu, utilizado para la construcción de armas de destrucción masiva. Los detectores de neutrones empleados habitualmente son contadores proporcionales de 3He, pero debido a la escasez de 3He, reportada desde 2009, se han hecho diferentes investigaciones...

  6. Neutron area monitor with passive detector

    Valero-Luna, Claudia; Guzmán-García, Karen Arlete; Borja-Hernández, Candy Gretel; Hernández-Dávila, Víctor Manuel; Vega-Carrillo, Héctor René
    Using Monte Carlo methods the responses of a passive neutron monitor area has been calculated. To detect thermal neutrons the monitor has a gold foil that is located at the center of a polyethylene cylinder. Impinging neutrons are moderated by polyethylene nuclei reaching the gold foil with the energy to induce activation through the reaction 197Au (n,γ) 198Au. The198Au decays emitting 0.411 MeV gamma rays with a half life of 2.7 days. The induced activity is intended to be measured with a gamma-ray spectrometer with a 3”Ø×3” NaI(Tl) scintillator and the saturation activity is correlated to the ambient dose equivalent....

  7. Study of a 10B+ZnS(Ag) neutron detector as an alternative to 3He-based detectors in Homeland Security

    Guzmán-García, Karen Arlete; Vega-Carrillo, Héctor René; Gallego Díaz, Eduardo F.; Lorente Fillol, Alfredo; Méndez-Villafañe, Roberto; González, Juan A.
    The response of a scintillation neutron detector of ZnS(Ag) with 10B was calculated, using the MCNPX Monte Carlo Code. The detector consists of four panels of polymethyl methacrylate (PMMA) and five thin layers of ~0.017 cm thick 10B+ZnS(Ag) in contact with the PMMA. The response was calculated for the bare detector and with different thicknesses of High-Density Polyethylene, HDPE, moderator for 29 monoenergetic sources as well as 241AmBe and 252Cf neutrons sources. In these calculations, the reaction rate 10B(n, α)7Li and the neutron fluence in the sensitive area of the detector 10B+ZnS(Ag) was estimated. Measurements were made at the Neutron...

  8. Neutron spectra and H*(10) of photoneutrons inside the vault room of an 18 MV LINAC

    Bañuelos-Frías, Alan; Borja-Hernández, Candy Gretel; Guzmán-García, Karen Arlete; Valero-Luna, Claudia; Hernández-Dávila, Víctor Manuel; Vega Carrillo, Héctor René
    Las estimaciones se llevaron a cabo utilizando métodos Monte Carlo donde una sala realista fue modelada incluyendo un fantoma de tejido equivalente. El término fuente para neutrones fue calculado usando la función de Tosi et al, la cual contabiliza los neutrones de evaporación y reacción directa. El espectro fue estimado usando dos diferentes distribuciones de energía. Los detectores fueron colocados en el plano donde se encuentra el isocentro. Dentro de la sala de tratamiento, como la distancia respecto al isocentro aumenta, la cantidad de neutrones y H*(10) se reduce, los neutrones dentro de la región de alta energía son desplazados...

  9. Passive neutron area monitor with TLD pairs

    Guzmán-García, Karen Arlete; Borja-Hernández, Candy Gretel; Valero-Luna, Claudia; Hernández-Dávila, Víctor Manuel; Vega-Carrillo, Héctor René
    The response of a passive neutron area monitor with pairs of thermoluminescent dosimeters has been calculated using the Monte Carlo code MCNP5. The response was calculated for one TLD 600 located at the center of a polyethylene moderator. The response was calculated for 47 monoenergetic neutron sources ranging from 1E(-9) to 20 MeV. Response was calculated using two irradiation geometries, one with an upper source and another with a lateral source. For both irradiation schemes the response was calculated with the TLD in two positions, one parallel to the source and another perpendicular to the source. The advantage of this passive...

  10. Comparación de tecnologías de reactores avanzados para un país sin energía nuclear

    Medrano Albert, Daniel
    En las últimas dos décadas, empresas del sector de la electricidad han desarrollado nuevos modelos de sus reactores nucleares a partir de los ya existentes. Este hecho ha dado lugar a las llamadas Generación III y Generación III+ de reactores nucleares. A raíz de esto se empezaron a desarrollar planes civiles de energía nuclear en numerosos países. Tras el accidente de Fukushima-Daiichi muchos de estos proyectos se paralizaron o se abandonaron como consecuencia del miedo y los daños originados por accidentes nucleares. Tras esto, las empresas rediseñaron sus modelos de reactores haciéndolos más seguros mediante la implantación de nuevos sistemas...

  11. Stability of Vacancy Loops close to Surfaces in α-Fe from Molecular Dynamics Simulations

    Rio Redondo, Emma del; Perlado Martín, José Manuel; Menéndez-Alfonso, R.; Aliaga Gonsálvez, María José; Caturla Terol, María José
    Molecular dynamics simulations to study the stability of vacancy clusters as a function of its distance and orientation with respect to the free surfaces are performed. Results show they are able to migrate to the free surfaces and recombine with it. Time for the absortion of the cluster by the free surfaces as a function of the temperature is calculated in order to obtain the migration energy activation.

  12. Deffect energetics in FeCr from empirical interatomic potentials

    Rio Redondo, Emma del; Victoria, Máximo Pedro; Perlado Martín, José Manuel; Sampedro, Jesus M.; Caturla Terol, María José
    We present a comparative study between two empirical potentials for the study of FeCr alloys. Vacancy, self- and mixed interstitials formation energies are investigated for both potentials in pure bcc Fe and pure bcc Cr. These results are compared to DFT values reported in literature. Some small Cr clusters in substitutional positions have also been studied in bcc Fe. Finally we have performed some calculations of the vacancy formation energy (Ev) depending on Cr concentration.

  13. The effect of Cr concentration on single interstitials stability in FeCr alloys

    Rio Redondo, Emma del; Perlado Martin, Jose Manuel; Caturla, María J.; Klaver, Peter; Caro, Alfredo; Serrano, M.
    Finding adequate materials to withstand the demanding conditions in future fusion and fission reactors is a real challenge in the development of these technologies. Structural materials are going to be subjected to high irradiation doses and operating temperatures which will affect and modify material properties at a microstructural level. Understanding the changes in the microstructure induced by irradiation is needed in order to predict the response of these materials, ensuring safe and reliable future power plants. High-Cr ferritic/martensitic steels are preferred candidate structural materials due to their high resistance to radiation effects and their good resistance against corrosion. On the...

  14. The effect of Cr concentration on single interstitials stability in FeCr alloys

    Rio Redondo, Emma del; Perlado Martin, Jose Manuel; Caturla, María J.; Klaver, Peter; Caro, Alfredo; Serrano, M.
    Finding adequate materials to withstand the demanding conditions in future fusion and fission reactors is a real challenge in the development of these technologies. Structural materials are going to be subjected to high irradiation doses and operating temperatures which will affect and modify material properties at a microstructural level. Understanding the changes in the microstructure induced by irradiation is needed in order to predict the response of these materials, ensuring safe and reliable future power plants. High-Cr ferritic/martensitic steels are preferred candidate structural materials due to their high resistance to radiation effects and their good resistance against corrosion. On the...

  15. Diseño del blindaje radiológico del Contenedor de Manejo de Cápsulas para el almacenamiento de combustible gastado en el Almacén Temporal Centralizado (ATC)

    Navarro Muñoz-Delgado, Pablo
    El almacenamiento temporal centralizado que se contempla para llevarlo a cabo en el territorio español tiene como objetivo fundamental la gestión y almacenamiento del combustible gastado, los residuos de alta actividad y los residuos especiales. Estos residuos procederán de las actividades de reprocesado así como del desmantelamiento de centrales nucleares españolas. El almacenamiento del combustible gastado y los residuos de alta actividad tendrá lugar en bóvedas, sin embargo los residuos especiales se almacenarán en naves de hormigón. Adicionalmente a la funcionalidad principal, el ATC está concebido para poder realizar una labor de investigación y análisis del comportamiento y características de los residuos...

  16. Discretization Error Estimation and Mesh Optimization for Plasma Edge Transport Simulations of Nuclear Fusion Tokamaks

    Riverola Calavia, Javier
    In nuclear fusion, tokamak devices are the most advanced technology of magnetic confinement, in which the divertor configuration allows to control plasma-edge motion and power and particle exhaust. In this sense, computational simulations are an indispensable tool to study and characterize the plasma-edge physics. A key aspect is the selection of a suitable mesh that discretizes the spatial domain and allows to capture accurately the steep gradients of state variables and complex behavior of the plasma-edge. In the first part of this work, different discretization error estimation methodologies are collected from the field of CFD to study their applicability to a...

  17. Análisis termohidráulico de la refrigeración del combustible nuclear mediante dinámica de fluidos computacional

    Vicente Sánchez, Pablo
    La refrigeración en el núcleo de los reactores de agua en ebullición se rige por la fenomenología propia de los flujos bifásicos. En ella se incluyen cambios de fase y regímenes de flujo muy diversos, que afectan a la interacción entre el refrigerante y las varillas de combustible y, en consecuencia, al rendimiento del reactor. Por ello entender en detalle el flujo en ebullición que caracteriza a estos reactores es de gran importancia a la hora de optimizar su diseño y prever su comportamiento en caso de una desviación respecto al funcionamiento normal. Con el presente trabajo se pretende obtener...

  18. Effect of activation cross section uncertainties in the assessment of primary damage for MFE/IFE low-activation steels irradiated in IFMIF

    Cabellos de Francisco, Oscar Luis; Sanz Gonzalo, Javier; García Herranz, Nuria; Otero, B.
    The present study is mainly aimed to provide the primary damage (displacements per atom, generation of solid transmutants and gas production rates) of structural materials irradiated in the high and medium flux test modules of the International Fusion Materials Irradiation Facility (IFMIF). We have investigated if the change of the composition during the irradiation time has effect on the prediction of the atomic displacements. The effect of the activation cross section uncertainties in the assessment of both solid transmutants and hydrogen and helium production is also analyzed. The results are provided elementby- element, so that the primary damage of any...

  19. Nuclear Data Uncertainty Propagation to Reactivity Coefficients of a Sodium Fast Reactor

    Herrero Carrascosa, José Javier; Ochoa Valero, Raquel; Martínez, J.S.; Díez, Carlos Javier; García Herranz, Nuria; Cabellos de Francisco, Oscar Luis
    Engineering of innovative reactor concepts requires computational tools capable of producing results with a high level of accuracy. These results are affected by different sources of uncertainty such as the ones coming from nuclear data. The assessment of the uncertainty levels on the design and safety parameters is mandatory. The uncertainty quantification applied here is based on the adjoint sensitivity analysis, where the sensitivities of design values to nuclear data are employed together with the nuclear data uncertainties to propagate these uncertainties to the design parameters. The European Sodium Fast Reactor (ESFR) is the innovative reactor model considered here, designed...

  20. El código nodal analítico ANDES para difusión en geometría 3D y multi-grupos: Desarrollo y Resultados

    Lozano Montero, Juan Andrés; García Herranz, Nuria; Aragonés Beltrán, José María
    La necesidad de métodos computacionales cada vez más exactos para la simulación de los fenómenos físicos presentes en los reactores nucleares actuales y futuros, requiere una aproximación multi-escala y multi-física. Este reto puede ser realizado mediante el acoplamiento de códigos best-estimate de neutrónica y termo-hidráulica. Con este objetivo, la tendencia actual en el campo de simulación de reactores es el desarrollo de una nueva generación de herramientas que sean fáciles de usar, modulares, intercambiables y de esta manera, integrables en plataformas comunes. Estas son las premisas que dieron lugar al proyecto integrado NURESIM dentro del 6º Programa Marco de la Unión...

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