Persona:
Juárez Mañas, Rafael

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0000-0001-7649-202X
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Juárez Mañas
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Rafael
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2022 - 20243
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Mostrando 1 - 3 de 3
  • Miniatura
    Publicación
    Nuclear scoping analysis of ITER bioshield top lid toward its preliminary design review
    (Elsevier, 2023-10-01) Bergman, J.; Loughlin, Martin; Le Tonqueze, Y.; Thompson, M.; Martínez Albertos, Pablo::virtual::3129::600; Sauvan, Patrick::virtual::3130::600; Juárez Mañas, Rafael::virtual::3131::600; Martínez Albertos, Pablo; Sauvan, Patrick; Juárez Mañas, Rafael; Martínez Albertos, Pablo; Sauvan, Patrick; Juárez Mañas, Rafael; Martínez Albertos, Pablo; Sauvan, Patrick; Juárez Mañas, Rafael
    During ITER operations, electronics located in the crane hall, which is above the tokamak, will be exposed to neutron and photon fields from both the plasma and the activated water. To protect the electronics, the implementation of dedicated shielding on the crane hall platform and the bioshield top lid is required. The design demands optimisation attending to constructability, weight limits, and radiation shielding requirements. This work evaluates eight shielding configurations by assessment of the neutron flux and dose accumulated over 4700 h of operation at 500 MW for electronics protection. This corresponds to a neutron wall load of 0.3 MW a/m² as specified in the ITER Project Specification. An intermediate-source approach has been followed with SRC-UNED, considering all relevant radiation sources while minimising the computational time required. Results were presented at the top lid Conceptual Design Review aiming to support decision-making. Further optimisation has since been performed to reach a top lid proposal for its Preliminary Design Review. All outcomes show that radiation levels above the north and south crane hall platforms are compatible with the critical electronics requirements.
  • Miniatura
    Publicación
    Computational study of the Nitrogen-16 source term in the ITER vacuum vessel cooling circuit through the coupling of system-level analysis code and CFD
    (Elsevier, 2024-08) De Pietri, Marco; Fiorina, C.; Le Tonqueze, Y.; Juárez Mañas, Rafael
    In ITER, the evaluation of the activated water radiation source and its impact on the radiological levels is necessary to demonstrate compliance with the safety requirements. The use of simplified or conservative approaches often results in the application of expensive constraints on the installation that impact its economics, operations, and construction schedule. In this work, we propose a novel methodology to calculate the activated water source term with a higher degree of realism. The methodology is based on the coupling of a system-level code with a Computational Fluid Dynamics (CFD) code in an explicit, one-way approach. We apply this methodology to the evaluation of the 16N radioisotope within the ITER Vacuum Vessel Primary Heat Transfer System (VV-PHTS) cooling circuit in a steady-state and transient scenarios. We chose this system since previous analyses of the VV-PHTS were done with simple, ad-hoc calculations that yielded results that differed by up to a factor of five, underscoring a higher level of uncertainty. As a result, we generate a computational model of the source term that can be used to evaluate the radiological condition surrounding the cooling systems during the operations.
  • Miniatura
    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, Rafael
    Critical 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 constraints