Persona: Ogando Serrano, Francisco M.
Cargando...
Dirección de correo electrónico
fogando@ind.uned.es
ORCID
0000-0002-2717-4647
Fecha de nacimiento
Proyectos de investigación
Unidades organizativas
Puesto de trabajo
Apellidos
Ogando Serrano
Nombre de pila
Francisco M.
Nombre
10 resultados
Resultados de la búsqueda
Mostrando 1 - 10 de 10
Publicación New developments in the MCUNED-Plus code for radiation transport and coupled transport-activation computational simulations in accelerator-based facilities(Elsevier, 2024-06-25) López Lorente, Víctor Daniel; Sauvan, Patrick; Sanz Pérez, Javier; Ogando Serrano, Francisco M.The radiation hazard is one of the major aspects of concern in the design of a facility where it exists a risk of exposure to ionizing radiation. The nuclear analysis for radioprotection purposes requires an accurate description of the radiation fields. This is especially true in accelerator-based facilities where several types of particles are producing the radiation fields. Radiation fields exist during the accelerator operation, but delayed radiation may also be significant for a long time after operation ends. The radiation fields of concern present during the operation are due to the secondary neutrons and photons emitted by the interaction of accelerated particles with the accelerator components (beam leakage) or with the target. The radiation present after the operation is the residual photon field produced by activated materials, these materials being activated by both accelerated particles and secondary neutrons. This residual radiation field is relevant in high intensity accelerators like IFMIF-DONES. In order to address these complex radiation transport simulations, the D1SUNED code has been updated and the new code release renamed as MCUNED-Plus. The new developments include improvements in the light-ion transport like the implementation of a variance reduction for the production of secondary particles, and a new kinematics to reproduce the angular distribution of secondary particles emitted after deuteron breakup reaction. The calculation of the residual photon field in accelerator facility has also been improved by allowing to evaluate both light-ions and secondary neutrons induced shutdown dose rate in a single coupled simulation.Publicación Sensitivity to nuclear data of the design of the IFMIF-DONES beam dump(Frontiers, 2023-06-05) López Ochoa, Víctor; Ogando Serrano, Francisco M.; Sauvan, PatrickDuring the commissioning and start-up phases of IFMIF-DONES, the 40MeV deuteron beam will be stopped in a conical beam stopper made of copper, giving rise to intense neutron fields. Accurate coupled deuteron-neutron transport simulations are required in order to prevent the potential risks to the workers andequipmentinvolved. However, theexperimental data concerning the neutron emission under these circumstances is scarce and limited to a particular range of energies. Different deuteron nuclear data libraries such as JENDL-5 and special f iles of TENDL-2021 exhibit some differences on the spectrum of the emitted neutrons. The differences are present in thehigh energy tails, beyond the available experimental data. Calculations of the prompt neutron fields have been performed employing both deuteron data libraries, as well as employing an estimation of the neutron energy-angle distribution derived from experimental data at different irradiation energies. Even though the high energy tails represent a small part of the flux, they have a major impact on the dose rates. The disparity of the results evinces large uncertainties in the IFMIF-DONES beam dump design process. Further experiments are required in order to resolve the differences among nuclear data libraries and reduce the uncertainty.Publicación GEOUNED: A new conversion tool from CAD to Monte Carlo geometry(Elsevier, 2024-05-30) Catalán Pérez, Juan Pablo; Sauvan, Patrick; García, J.; Alguacil Orejudo, Javier; Ogando Serrano, Francisco M.; Sanz Pérez, JavierThe GEOUNED code is specifically designed to convert CAD models, defined using the B-rep approach, into MC radiation transport models, defined using the CSG approach, and vice versa from MC to CAD. This code incorporates standard features commonly found in conversion tools, including decomposition, conversion, and automatic void generation. Additionally, it introduces innovative features, mainly in the automatic void generation part, which are described in this article. GEOUNED has demonstrated successful application in highly detailed 3D models used in fusion neutronics, which are known for their complex geometries, particularly those utilized in ITER. The article includes examples showcasing GEOUNED’s performance in these challenging models, as well as custom applications that highlight its flexibility in addressing non-standard problems. The code is open-source and utilizes Open CASCADE as the geometry engine, with FreeCAD serving as the Python API.Publicación Preliminary nuclear analysis of HYLIFE-III: A thick-liquid-wall chamber for inertial fusion energy(ELSEVIER, 2024-05) Ogando Serrano, Francisco M.; Tobin, Michael T.; Meier, Wayne R.; Farga Niñoles, Gonzalo; Marian, Jaime; Reyes, Susana; Sanz Gozalo, Javier; Galloway, Conner D.This paper provides neutronics analyses of the Xcimer Energy Corporation (XEC) HYLIFE-III Inertial Fusion Energy Power Plant concept. This design is based on the thick-liquid-wall HYLIFE-II reactor, but with much larger fusion yield, due to enhanced driver energy. Although HYLIFE-II neutronics was extensively studied, the differences between the two concepts suggested new analyses are required. Further, computational advances in neutronics calculations also motivate updating results from more than 25 years ago. The neutron spectra emitted from the much larger yield hybrid Inertial Confinement Energy (IFE) target is presented. Selected breeding materials are compared by tritium breeding ratio (TBR), activation, and first wall protection where FLiBe is proposed as the overall best choice. The first wall neutron activation and structural damage, including gas generation in the wall, is presented for various FLiBe protective wet-wall thicknesses. Final optic neutron damage is also examined and results in optics long enough lifespan with moderate annealing temperatures. Some limited comparisons of first wall damage for ICF and Magnetic Confinement Fusion relevant conditions is presented. HYLIFE-III with FLiBe as the breeding material and first wall protection provides a very robust TBR above 1.2.Publicación Construction of GVR weight windows maps from very low density transport simulations(Elsevier, 2024-05) Farga Niñoles, Gonzalo; Ogando Serrano, Francisco M.; Alguacil Orejudo, Javier; Sauvan, PatrickFusion-related facilities present relevant neutron radiation fields even after penetrating through a considerable thickness of shielding material. Neutronic analyses performed via Monte Carlo codes, then, need Global Variance Reduction (GVR) techniques so that low statistical uncertainty is reached efficiently throughout the geometry. Mesh-based Weight Windows is a flexible methodology used extensively for variance reduction purposes, both for Local and Global Variance Reduction. Purely stochastic GVR methodologies based on Weight Windows usually construct weight maps so that they are proportional to the forward particle flux, which is unknown a priori. Therefore, an iterative cycle is established. In each iteration, a weight map is obtained from the forward flux that allows the next iteration to reach further into the geometry, until all of it is populated. However, this iterative cycle may take a considerable amount of computer time, as many iterations are needed to fully populate the geometry. An alternative to achieve relevant penetration in a single iteration is to perform calculations at very low densities. However, a reconstruction method is needed to estimate the flux at the real density. This work studies a scheme to reconstruct the fluxes from low density calculations and compares it to already existing techniques.Publicación Shutdown dose rates calculations due to light ions induced activation using D1S methodology(ELSEVIER, 2021-06-01) López Ochoa, Víctor; Sauvan, Patrick; Ogando Serrano, Francisco M.One of the main radiation sources in nuclear facilities, which cause exposure of workers conducting maintenance activities, is the decay of radioactive nuclides. The determination of these radiation fields usually requires both radiation transport and activation calculations. The Direct-one-Step methodology allows obtaining response functions associated to the residual activity with a single Monte Carlo transport calculation. This methodology has been widely used in the analysis of nuclear fusion installations like ITER, JET or DEMO, proving to be a very efficient tool for Shutdown Dose Rate calculations. Yet, this methodology has only been applied when the material activation is due to the interaction with a neutron flux. Since, typically, in particle accelerators the D1S assumptions are met, it is proposed in this work to apply the D1S methodology to material activation induced by light ions interactions, namely: protons and deuterons. This methodology has been implemented in the D1SUNED code. In order to show its performance, the D1SUNED has been used to calculate the SDR in the LIPAc geometry, resulting in a good convergence with a reference calculation.Publicación A full and heterogeneous model of the ITER tokamak for comprehensive nuclear analyses(Nature Research, 2021-01-04) Juárez Mañas, Rafael; Pedroche Sánchez, Gabriel; Loughlin, M. J.; Pampin, R.; Martínez Albertos, Pablo; De Pietri, Marco; Alguacil Orejudo, Javier; Ogando Serrano, Francisco M.; Sauvan, Patrick; López Revelles, Antonio Jesús; Kolsek, Aljaz; Polunovskiy, E.; Fabbri, M.; Sanz Pérez, JavierITER is the flagship project, conceived as an experiment to select and develop the technologies for the first demonstration reactor, DEMO. Nuclear analysis is a core discipline in support of the design, commissioning and operation of the machine. To date it has been conducted with increasingly detailed partial models, which represented toroidal segments of the tokamak. However, the limitations of this methodology became evident as estimates of quantities relevant to design, safety and operation showed unquantifiable uncertainties, which is a risk. Here, we present a detailed and realistic 360° MCNP model of the ITER tokamak called E-lite. We demonstrate the model’s usability and practicality. Two examples are used to illustrate qualitatively and quantitatively how it solves previously intractable problems with marked benefits for the future nuclear analysis of ITER, with applications to DEMO and future reactors. E-lite constitutes a milestone in the field of nuclear analysis in terms of realism in the evaluation of key quantities.Publicación D1SUNED system for the determination of decay photon related quantities(Elsevier, 2019-11-18) Sauvan, Patrick; Juárez Mañas, Rafael; Pedroche Sánchez, Gabriel; Alguacil Orejudo, Javier; Catalán Pérez, Juan Pablo; Ogando Serrano, Francisco M.; Sanz Pérez, JavierThe neutron fields alter the radioactive inventory of the irradiated materials leading to subsequent decay photon fields. In some cases, these fields are of relevance either intended or undesired, normally involving safety and economics aspects. The determination of these fields can be of paramount complexity if high spatial resolution is required. The determination of these fields requires both radiation transport and activation calculations. The Direct-one-Step methodology, under the assumption that the radioactive inventory activity is lineal with the neutron flux, can address the problem with only one coupled neutron-photon transport calculation. In this paper the D1SUNED code for the calculation of decay photon field and related quantities using D1S methodology is presented. Calculation capabilities including the determination of 3D decay photon sources, filtering options, and other relevant features are presented. In terms of computational load, D1SUNED, which is based on MCNP5 code, presents improvements with respect to MCNP. It can save a 79% of the RAM memory used to store the geometry, a 98% of the loading time, and an acceleration of a factor two by controlling the decay photon emission, boosting the simulations for ITER-like problems. D1SUNED has been validated with the FNG benchmark experiment considering the null hypothesis rejection test and the C/E ratio with very positive results. As a consequence, D1SUNED has become a reference tool for the design of ITER, and other relevant nuclear fusion facilities.Publicación ITER plasma source and building modelling to produce radiation maps(IOP Publishing, 2018-09-27) Juárez Mañas, Rafael; Catalán Pérez, Juan Pablo; López Revelles, Antonio Jesús; Sauvan, Patrick; Jakhar, Shrichand; Polunovskyi, Edouard; Loughlin, Michael; Sanz Gozalo, Javier; Ogando Serrano, Francisco M.The ITER Tokamak Complex is the civil structure that will host the ITER Tokamak and the largest part of the associated systems. The dimensions are 120 m × 80 m × 60 m, built mostly of concrete, with over one thousand penetrations. During ITER operation, a radiation field will spread throughout the complex from diverse radiation sources. It must be characterized to check the compliance with the limits for electronics allocation and human intervention. However, the production of radiation maps in the ITER Tokamak Complex is a task of paramount sophistication due to challenges to adequately model in MCNP the radiation sources involved. In this work, two important methodological upgrades are presented. First, a new MCNP model of the Tokamak Complex, conceived to be computationally stable while capturing a conservative representation of the baseline. Second, a novel approach to model the plasma source, called a mosaic source, allows an unprecedented degree of realism and accuracy in terms of capturing the port specificities. Both represent a step change in the capacity to produce ITER radiation maps with increased reliability, augmenting previous versions. Examples of partial radiation maps are provided considering both methodological upgrades.Publicación Beam-facing material selection for mitigation of residual doses in the HEBT of IFMIF-DONES(ELSEVIER, 2024) Ogando Serrano, Francisco M.; Macià, Llorenç; López Ochoa, Víctor; Podadera Aliseda, Ivan; Sánchez Herranz, Daniel; https://orcid.org/0000-0001-5599-336X; https://orcid.org/0000-0002-3459-4631; https://orcid.org/0000-0001-7090-2550IFMIF-DONES will be an irradiation facility based on a 40 MeV deuteron accelerator. Unavoidable beam losses along the accelerator result in deuterium interactions with the beam facing materials of the vacuum beam pipe, some of them leading to material activation. The initial design of the beam pipe was based on stainless steel, but an evaluation of the residual doses from the pipe showed high values after operation of the accelerator. The accelerator beam line must be periodically maintained, and excessive cooling times for reaching acceptable dose levels may result in poorer availability of the facility. A deeper study of the High Energy Beam Transport line (HEBT) showed that a direct reaction between deuterons and iron in steel resulted in the production of Co-56, with a half-life of 77 days. This radioisotope is the main source of the radiation and makes it impractical to wait for a proper attenuation of the radiation field. A redesign of beam line elements has been performed to avoid the presence of stainless steel as a beam facing material and to replace it with aluminum where possible, resulting in faster decay of residual doses. This work contains a summary of the nuclear analysis performed for the computation of residual doses with stainless steel beam pipe, stressing the uncertainties of the calculations, based on the limited availability of nuclear data for the relevant nuclear reaction Fe56 (d,2n). The proposed replacement of element materials is also described, and an updated nuclear analysis shows the reduction of residual radiation, and its impact on possible maintenance operations.