Recursos de colección

Archivo Digital UPM (107.543 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 282

  1. Passive neutron area monitor with TLD pairs

    Guzmán-García, Karen Arlete; Borja Hernández, C.G.; Valero Luna, C.; Hernández Dávila, V.M.; 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...

  2. 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...

  3. 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.

  4. 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.

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. Development and Performance of the ANDES/COBRA-III Coupled System in Hexagonal-Z Geometry

    Lozano Montero, Juan Andrés; Jiménez Escalante, Javier; García Herranz, Nuria; Aragonés Beltrán, José María
    In this paper, the extension of the nodal diffusion code ANDES, based on the ACMFD method, to hexagonal geometry is presented, as well as its coupling with the thermal-hydraulic (TH) code COBRA-IIIc/MIT-2 for such hexagonal problems. In extending the ACMFD method to hexagonal assemblies, triangular-Z nodes are used, taking advantage of the mesh refinement capabilities implicit within that geometry. The existing TH coupling for Cartesian geometry applications has also been extended to hexagonal problems, with the capability to model the core using either assembly wise channels (hexagonal mesh) or a higher refinement with six channels per fuel assembly (triangular mesh)....

  14. Sensitivity/Uncertainty Analysis for BWR Configurations of Exercise I-2 of UAM Benchmark

    García Herranz, Nuria; Garrido, J.; Cabellos de Francisco, Oscar Luis
    In order to evaluate the uncertainties in prediction of lattice-averaged parameters, input data of core neutronics codes, Exercise I-2 of the OECD benchmark for uncertainty anal-ysis in modeling (UAM) was proposed. This work aims to perform a sensitivity/uncertainty analysis of the BWR configurations defined in the benchmark for the purpose of Exercise I-2. Criticality calculations are done for a 7x7 BWR fresh fuel assembly at HFP in four configurations: single unrodded fuel assembly, rodded fuel assembly, assembly/reflector and assembly in a color-set. The SCALE6.1 code package is used to propagate cross section covariance data through lattice physics calculations to both...

  15. Nuclear data sensitivity and uncertainty assessment of sodium voiding reactivity coefficients of an ASTRID-like Sodium Fast Reactor

    García Herranz, Nuria; Panadero, Anne Laurène; Martínez Campo, Ana; Pelloni, Sandro; Mikityuk, K.; Pautz, A.
    The EU 7th Framework ESNII+ project was launched in 2013 with the strategic orientation of preparing ESNII for Horizon 2020. ESNII stands for the European Industrial Initiative on Nuclear Energy, created by the European Commission in 2010 to promote the development of a new generation of nuclear systems in order to provide a sustainable solution to cope with Europe’s growing energy needs while meeting the greenhouse gas emissions reduction target. The designs selected by the ESNII+ project are technological demonstrators of Generation-IV systems. The prototype for the sodium cooled fast reactor technology is ASTRID (standing for Advanced Sodium Technological Reactor for...

  16. Sensitivity of Shallow Land Burial to neutron environment and activation cross sections in IFE thick-liquid concepts

    Cabellos de Francisco, Oscar Luis; Sanz, J.; Reyes, S.; Latkowski, J.; García Herranz, Nuria
    A comprehensive assessment on the eligibility of reduced activation (RA) steels as structural chamber material in Inertial Fusion Energy (IFE) thick-liquid concepts is performed. As far as alloying elements, it is shown that the activation of tungsten is a question to debate. Regarding impurity elements, it is analyzed if they could question the possibility of obtaining real RA steels for shallow land burial (SLB). The effect of the thickness of the liquid wall on the SLB response of alloying and impurity elements is computed. And above all, we have estimated the impact of cross section uncertainties when addressing the former...

  17. Analytic Coarse-Mesh Finite-Difference Method Generalized for Heterogeneous Multidimensional Two-Group Diffusion Calculations

    García Herranz, Nuria; Cabellos de Francisco, Oscar Luis; Aragonés Beltrán, José María; Ahnert Iglesias, Carolina
    In order to take into account in a more effective and accurate way the intranodal heterogeneities in coarse-mesh finite-difference (CMFD) methods, a new equivalent parameter generation methodology has been developed and tested. This methodology accounts for the dependence of the nodal homogeneized two-group cross sections and nodal coupling factors, with interface flux discontinuity (IFD) factors that account for heterogeneities on the flux-spectrum and burnup intranodal distributions as well as on neighbor effects. The methodology has been implemented in an analytic CMFD method, rigorously obtained for homogeneous nodes with transverse leakage and generalized now for heterogeneous nodes by including IFD heterogeneity factors....

  18. The Analytic Coarse-Mesh Finite Difference Method for Multigroup and Multidimensional Diffusion Calculations

    Aragonés Beltrán, José María; Ahnert Iglesias, Carolina; García Herranz, Nuria
    In this work we develop and demonstrate the analytic coarse-mesh finite difference (ACMFD) method for multigroup - with any number of groups - and multidimensional diffusion calculations of eigenvalue and external source problems. The first step in this method is to reduce the coupled system of the G multigroup diffusion equations, inside any homogenized region (or node) of any size, to the G independent modal equations in the real or complex eigenspace of the G × G multigroup matrix. The mathematical and numerical analysis of this step is discussed for several reactor media and number of groups. As a second step,...

  19. Transmutation Analysis of Realistic Low-Activation Steels for Magnetic Fusion Reactors and IFMIF

    Cabellos de Francisco, Oscar Luis; Sanz, J.; García Herranz, Nuria; Díaz, S.; Reyes, S.; Piedloup, S.
    A comprehensive transmutation study has been performed for steels considered in the selection of structural materials for magnetic and inertial fusion reactors for the international fusion materials irradiation facility (IFMIF) neutron irradiation environment, as well as in the international thermonuclear experimental reactor (ITER) and a fusion demonstration reactor (DEMO) for comparison purposes. An element by element transmutation approach is used in the study, addressing the generation of: (1) H and He and (2) solid transmutants. The IEAF 2001 activation library and the activation code ACAB were applied in the IFMIF transmutation analysis, after proving the applicability of ACAB for transmutation calculations...

  20. Methods and Results for the MSLB NEA Benchmark Using SIMTRAN and RELAP5

    Aragonés Beltrán, José María; Ahnert Iglesias, Carolina; Cabellos de Francisco, Oscar Luis; García Herranz, Nuria; Aragonés Ahnert, Vanessa
    The purpose of this paper is first to discuss the methods developed in our three-dimensional pressurized water reactor core dynamics code SIMTRAN and its coupling to the system code RELAP-5 for general transient and safety analysis. Then, we summarize its demonstration application to the Nuclear Energy Agency (NEA)/ Organization for Economic Cooperation and Development (OECD) Benchmark on Main Steam Line Break (MSLB), co-sponsored by the U.S. Nuclear Regulatory Commission (NRC) and other regulatory institutions. In particular, our work has been supported by the Spanish “Consejo de Seguridad Nuclear” (CSN) under a CSN research project. Our results for the steady states and...

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