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Fradera J.,Idom Nuclear Services | Colomer C.,Idom Nuclear Services | Fabbri M.,Idom Nuclear Services | Martin M.,Idom Nuclear Services | And 6 more authors.
Fusion Engineering and Design | Year: 2015

The present work exposes the 3D thermal-hydraulic analysis of the Irregular Sector number 2 (IrS#2) of the ITER Vacuum Vessel (VV) by means of CFD (computational fluid dynamics). IrS#2 geometry has been simplified and healed in order to be suitable for CFD analysis. A polyhedral cell based mesh has been generated so as to enhance accuracy and calculation stability. Nuclear heat deposition has been implemented through several subroutines and an in-house MCNP data converter. Water coolant and stainless steel shell are solved coupled as a steady-state conjugate heat transfer problem in order to assess the impact of the nuclear heat deposition on the IrS#2 cooling scheme. Hence, the IrS#2 is simulated as a whole without splitting the domain. Results show the total IrS#2 pressure drop as well as the flow and temperature distribution all over the IrS#2. Moreover, heat transfer coefficient has been calculated at the water-shell interface in order to assess the behavior of shell cooling scheme. Velocity magnitude in the water coolant has an average value of 2 cm/s and the inboard to outboard mass flow rate distribution is 10.2% and 89.8% respectively. Pressure drop, mainly at inlet and outlet ducts, is of 60.21 kPa. Temperature at the liquid-solid interface has an average value of 106.4 °C and the heat transfer coefficient (HTC) stays always above 638 W/(m2 °C), way above the limit of 500 W/(m2 °C). Shell temperature stays at an average value of 130.0 °C. Exposed results, with a significant importance regarding design and safety, give a valuable insight on current cooling scheme and system behavior for the IrS#2 of the ITER VV. © 2015 Elsevier B.V. All rights reserved.

Velarde M.,Technological University of Madrid | Fradera J.,Idom Nuclear Services | Perlado J.M.,Technological University of Madrid | Zamora I.,Idom Nuclear Services | And 3 more authors.
Journal of Physics: Conference Series | Year: 2016

The present work presents an example of the application of an integral methodology based on a multiscale analysis that covers the whole tritium cycle within a nuclear fusion power plant, from a micro scale, analyzing key components where tritium is leaked through permeation, to a macro scale, considering its atmospheric transport. A leakage from the Nuclear Power Plants, (NPP) primary to the secondary side of a heat exchanger (HEX) is considered for the present example. Both primary and secondary loop coolants are assumed to be He. Leakage is placed inside the HEX, leaking tritium in elementary tritium (HT) form to the secondary loop where it permeates through the piping structural material to the exterior. The Heating Ventilation and Air Conditioning (HVAC) system removes the leaked tritium towards the NPP exhaust. The HEX is modelled with system codes and coupled to Computational Fluid Dynamic (CFD) to account for tritium dispersion inside the nuclear power plants buildings and in site environment. Finally, tritium dispersion is calculated with an atmospheric transport code and a dosimetry analysis is carried out. Results show how the implemented methodology is capable of assessing the impact of tritium from the microscale to the atmospheric scale including the dosimetric aspect. © Published under licence by IOP Publishing Ltd.

Fradera J.,Idom Nuclear Services | Velarde M.,Institute of Nuclear Fusion Technological University of Madrid | Perlado J.M.,Institute of Nuclear Fusion Technological University of Madrid | Colomer C.,Idom Nuclear Services | And 6 more authors.
Proceedings - Symposium on Fusion Engineering | Year: 2016

Tritium leakages are a major concern regarding nuclear power plants, not only in commercial fission power plants, but also in future fusion power plants. According to recent data collected by the NRC [1], 45 commercial NPPs in the US report leaks or spills involving tritium at some time during their operating history, although no threat to the public has been detected by the regulator [2]. Future fusion reactors, as for example those being studied in the ITER and NIF experiments, will breed tritium from other elements to use it as fuel. Hence, the need for preventing and containing tritium leakages, as it is done with any other contaminant, turns out to be a key issue. © 2015 IEEE.

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