Persona: Sanz Gozalo, Javier
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Sanz Gozalo
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Javier
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Publicación Improved radiation shielding analysis considering vector calculus(Wiley, 2020-09-08) Juárez Mañas, Rafael; Loughlin, Michael; López Revelles, Antonio Jesús; Pedroche Sánchez, Gabriel; Kolsek, Aljaz; Sauvan, Patrick; Sanz Gozalo, JavierThe future of nuclear energy in the energy mix faces a permanent scrutiny of safety aspects in conciliation with bridled costs, either fission- or fusion-based. This affects to all the exciting milestones pursued in XXIst. To name few in the field of fission, the deployment of the IVth generation reactors is expected or the definitive solution to the radioactive wastes is sought. A mention apart is made to fusion technology, with ITER as the flagship project. It seeks a virtually infinite energy source, intrinsically safe and with reduced radioactive waste production with respect to fission the first commercial reactor. All these, and many other endeavors, share the operation of sophisticated devices in the presence of intense ionizing radiation fields. Humans and electronics must be protected to ensure safe and reliable performance, while shielding normally represents a large fraction of the budget. This involves nuclear analysis in the design phase to forecast the radiation conditions. The complexity of the simulation of 3D radiation fields that is computationally affordable nowadays is unprecedented. While sophistication in geometries and source definitions has become routine, the resulting complexity of these scalar fields makes their analysis increasingly difficult. The need of enhancement of the analysis techniques is evident today. Vector calculus is proposed following a physical interpretation of the field lines that boosts the analysis capabilities. It identifies the trajectories around which shielding is weakest in an automated errorless and effortless approach. Its power is illustrated with an example relevant to the ITER reactor.Publicación Shielding conceptual designs of ITER TCP ports to protect electronics(Elsevier, 2022-01-18) Martínez Albertos, Pablo; Pedroche Sánchez, Gabriel; Dremel, M.; Pearce, R.; Loughlin, M.; Le Tonqueze, Y.; Sanz Gozalo, Javier; Juárez Mañas, RafaelCritical electronics of ITER Tokamak, hosted in the shielded corners (SC) of the Tokamak Building (B11), must operate under acceptable neutronic flux conditions (≤10 n⋅cm 2⋅s 1) to minimize single event effects. During machine operation and at lower level (B1), both the Torus Cryopumps (TCP) ports location within B11 and their pumping efficiency constraints are factors contributing to the radiation environment in the SC. Although previous studies have addressed the transmission of radiation out the vessel of TCP ports, none of them have assessed the impact of such radiation beyond the Port Cell. In this work, different TCP shielding configurations were evaluated at B1 level of B11 due to plasma neutrons emerging from the six TCP ports only. MCNP and dedicated computational tools were used to perform the radiation transport calculations. Albeit being a partial study, the examination of the compatibility between the TCP plasma neutron flux and the electronics limit in the SC has been addressed, while considering the combined effect of the shielding design and the building walls, lintels and doors in the results. We present a combined shielding case that reduces the neutron flux to a range of 1.3–9.3 n⋅cm 2⋅s 1 depending on the location, which is compatible with the limit while respecting pumping efficiency and assembly difficulty constraintsPublicación ACABLoop simulation tool: Improving the activation prediction of flowing PbLi alloy in support of DEMO fusion reactor design(ELSEVIER, 2024) García Camacho, Mauricio; Catalán Pérez, Juan Pablo; Sanz Gozalo, JavierPbLi alloy as breeder material is considered within the EUROfusion Programme in the Water-Cooled Lithium-Lead blanket concept of DEMO fusion reactor. The PbLi travels along loops entering and leaving the Breeding Blanket for recovering the produced tritium, removing generated impurities and activated corrosion products, etc. Prediction of activation-related responses in the flowing PbLi is a key safety issue in support of DEMO design. Traditionally, the activation inventory generated in the flowing PbLi has been calculated considering a simplistic approach, valid only for a pre-conceptual analysis. Additionally, the simulation of some phenomena is not possible when using that simple methodology. ACABLoop has been conceived as a tool to overcome such limitations predicting more realistically the activation of the PbLi alloy, providing all the information related to the generated isotopic inventory in the fluid. Status of ACABLoop development is presented as well as some applications for PbLi activation in DEMO loops, proving its suitability for fusion activation calculations. Additionally, a promising first validation of ACABLoop using a water loop and a D-T fusion neutron spectrum is shown. Last improvements of ACABLoop are devoted to allowing incorporation of CFD information as a tool for increasing the reliability in some specific situations.Publicación Nuclear analysis of the ITER Torus Cryopumps(IOP Publishing, 2019-09-09) Pedroche Sánchez, Gabriel; López Revelles, Antonio Jesús; Kolsek, Aljaz; Dremel, Matthias; Bansal, Gurpreet; Pearce, Robert; Sanz Gozalo, Javier; Juárez Mañas, RafaelThe ITER Tokamak will feature six torus cryopumps (TCP) to maintain the vacuum requirements inside the vacuum vessel for plasma operation. They will be connected to the ITER vacuum vessel through the lower ducts, which have limited shielding to ensure an efficient pumping. Therefore, these ducts will represent a relevant path for radiation to travel from the plasma and affect diverse aspects of the ITER facility, such as the electronics allocation or the maintenance operations during the machine shutdown. Previous analyses have addressed these important aspects. Nonetheless, limitations in those studies and design evolution have justified a new analysis, specifically dedicated to the TCP final design review. The results of the nuclear analysis are presented here focusing on the B1 level port cell #4. The TCP design and the associated and neighboring equipment have evolved and updated models have been considered. The TCP modelling has required an explicit heterogeneous treatment of the internal parts. The radiation source from the divertor cooling water pipes running along the port cell ceiling has been considered with the latest available source definition. In terms of methodology, one major improvement has been the modelling of the radiation transmission from C-model to the Tokamak Complex model. Another important improvement has been the consideration of D1SUNED for the determination of shutdown dose rates, covering a broader fraction of the radioactive inventory than in previous studies. The following quantities have been determined: neutron flux, absorbed dose to silicon, 1 MeV equivalent neutron fluence and shutdown dose rates (SDDR) after 106 s of cooling time. Finally, a set of proposals have been made to considerably mitigate the SDDR after 106 s of cooling. This work represents a realistic and matured source of information of the radiation environment in the ITER TCP port cells as presented in the final design review.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 Update in the nuclear responses of the European TBMs for ITER during operation and shutdown(Elsevier, 2018-07-06) Juárez Mañas, Rafael; López Revelles, Antonio Jesús; Sauvan, Patrick; Pedroche Sánchez, Gabriel; Kolsek, Aljaz; Alguacil Orejudo, Javier; Ugolini, Daniele; Vallory, Joelle; Ricapito, Italo; Poitvein, Yves; Calvo, Francisco; Sanz Gozalo, JavierThe depiction of the nuclear responses of the ITER European Test Blanket Modules (TBMs), Helium Cooled Lithium Lead (HCLL) and Helium Cooled Pebbles Bed (HCPB) is presented in this work. Following important components update, and important methodological advances, the nuclear heat and the tritium production have been revisited, giving new estimations 10% higher than the previous evaluation for nuclear heat in both TBMs and to 15% higher for HCPB T production. This has an impact on the thermo-mechanical design of the TBM and the tritium handling. In addition, the Shutdown Dose Rates in the respective port interspace have been characterized in local approach. It shows a performance that could imply compatibility with planned in-situ maintenance activities when analysed in global approach, an improvement with respect to previous evaluations.Publicación Fast generation of parametric neutronic models for stellarators. Coupling HeliasGeom and GEOUNED(ELSEVIER, 2024) Alguacil Orejudo, Javier; Catalán Pérez, Juan Pablo; Palermo, Iole; Sosa, David; Lion, Jorrit; Warmer, F.; Sanz Gozalo, Javier; https://orcid.org/0000-0001-8725-8167; https://orcid.org/0009-0000-5319-5575; https://orcid.org/0000-0002-6249-2368The operation of the Wendelstein 7-X has highlighted stellarators as potential fusion power reactors. As a consequence, the pre-conceptual design of the next HELIAS stellarator has started in the framework of EUROfusion. During these first stages, it is essential to assess the feasibility of various stellarator concepts. It is important to emphasize that these concepts can vary significantly in terms of their overall shape and allocation of space for each component, including the vacuum vessel, breeding blankets, among others. Although pre-conceptual neutronic analysis can be conducted using straightforward yet representative neutronic models, such as simplified multilayer models with minimal geometric details, the intricate shape of stellarators presents challenges to produce them quickly. This issue prevents the effective parametric optimization of the concepts, creating a bottleneck in the design of HELIAS. In order to overcome this problem, we are developing a computational workflow for the fast production of parametric stellarator neutronic MCNP models. This work presents the current status of the scheme composed of two steps: HeliasGeom for the production of parametric multilayer CAD models, and GEOUNED for the translation of these models to MCNP CSG neutronic models.Publicación Development of a methodology to estimate the statistical SDR uncertainty with R2S-UNED(ELSEVIER, 2021) Alguacil Orejudo, Javier; Catalán Pérez, Juan Pablo; Sanz Gozalo, Javier; Sauvan, Patrick; https://orcid.org/0000-0002-9128-8817The Rigorous-Two-Steps (R2S) is one of the most useful methods to estimate the Shutdown Dose Rate (SDR). The most advanced R2S tools couple neutron and photon transport, which are often simulated using Monte Carlo (MC) codes, through an activation simulation using mesh-based techniques to improve the spatial resolution of the neutron flux and the decay gamma source. One of the problems of the methodology is that the statistical uncertainty of the neutron flux due to the MC method used by the transport codes is not considered by most R2S implementations. Consequently, larger tolerance must be assumed affecting to the design of the nuclear facilities. This article describes a scheme allowing the calculation of the SDR statistical uncertainty without any additional assumptions than those used in the R2S methodology. The approach proposed in this article is suitable for cell- and mesh-based R2S implementations. In this work, the methodology was implemented in the R2S-UNED code. The accurate application of the methodology requires the full the neutron flux uncertainty (covariance matrix) as input data. MCNP was modified to calculate this matrix, although, it cannot be calculated for most of the realistic R2S simulations due to its size. If that is the situation, we propose a guideline to reduce the size of the covariance matrix to be calculated according to its element contribution to the SDR. When this guideline cannot be applied, the methodology still allows calculating the upper and lower SDR uncertainty bounds. In this article, the guideline is applied to the calculation of the SDR uncertainty in the computational benchmark of ITER. In addition, we also study the possible impact of the neutron flux correlation degree on the SDR uncertainty in this benchmark.Publicación MCNP model of the ITER Tokamak Complex(Elsevier, 2018-04-11) López Revelles, Antonio Jesús; Catalán Pérez, Juan Pablo; Kolsek, Aljaz; Juárez Mañas, Rafael; Rodríguez García, Raquel; García Camacho, Mauricio; Sanz Gozalo, JavierThe Tokamak Complex will accommodate the ITER tokamak and some of the plant systems needed for the machine operation. In order to obtain radiation maps in the Tokamak Complex, a new MCNP model was released on September 2016. This model, based on a conservative representation of the latest baseline design, represents a version controlled, computationally stable, user-friendly and easy-to-update and maintain MCNP input of the Tokamak Complex. Every modification of the initial CAD models was reviewed, recorded and version controlled. The MCNP model of the Tokamak Complex uses the most stable MCNP geometry implementations, avoiding the use of universes and macrobodies. The input exhibits a low particle loss rate (<10−9) when running in void with a dispersed isotropic source. It is strongly organized and profusely commented. Information about the level, building, room, system and material is provided in the definition of every cell. The 36862 cells and 57085 surfaces are arranged by levels and by buildings. The cells are also arranged by rooms and by systems, resulting in a room-oriented organization of the model, which allows an easy isolation of every room.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.