Mhd r&d activities for liquid metal blankets

According to the most recently revised European design strategy for DEMO breeding blankets, mature concepts have been identified that require a reduced technological extrapolation towards DEMO and will be tested in ITER. In order to optimize and finalize the design of test blanket modules, a number of issues have to be better understood that are related to the magnetohydrodynamic (MHD) interactions of the liquid breeder with the strong magnetic field that confines the fusion plasma. The aim of the present paper is to describe the state of the art of the study of MHD effects coupled with other physical phenomena, such as tritium transport, corrosion and heat transfer. Both numerical and experimental approaches are discussed, as well as future requirements to achieve a reliable prediction of these processes in liquid metal blankets

Design and Integration of the WCLL Tritium Extraction and Removal System into the European DEMO Tokamak Reactor

The latest progress in the design of the water-cooled lithium-lead (WCLL) tritium extraction and removal (TER) system for the European DEMO tokamak reactor is presented. The implementation and optimization of the conceptual design of the TER system are performed in order to manage the tritium concentration in the LiPb and ancillary systems, to control the LiPb chemistry, to remove accumulated corrosion and activated products (in particular, the helium generated in the BB), to store the LiPb, to empty the BB segments, to shield the equipment due to LiPb activation, and to accommodate possible overpressure of the LiPb. The LiPb volumes in the inboard (IB) and outboard (OB) modules of the BB are separately managed due to the different pressure drops and required mass flow rates in the different plasma operational phases. Therefore, the tritium extraction is managed by 6 LiPb loops: 4 loops for the OB segments and 2 loops for the IB segments. Each one is a closed loop with forced circulation of the liquid metal through the TER and the other ancillary systems. The design presents the new CAD drawings and the integration of the TEU into the tokamak building, designed on the basis of an experimental characterization carried out for the permeator against vacuum (PAV) and gas-liquid contactor (GLC) technologies, the two most promising technologies for tritium extraction from liquid metal

Phosphorites, Co-rich Mn nodules, and Fe-Mn crusts from Galicia Bank, NE Atlantic: Reflections of Cenozoic tectonics and paleoceanography

A wide variety of marine mineral deposits were recovered from 750 to 1400 m water depths on Galicia Bank, Iberian margin. Mineral deposits include: (1) carbonate fluorapatite phosphorite slabs and nodules that replaced limestone and preserved original protolith fabric. (2) Ferromanganese vernadite crusts with high Mn and Fe (Mn/Fe51) contents, and thick stratabound layers consisting mainly of Mn (up to 27% MnO) and Fe (15% Fe2O3), which impregnated and replaced the phosphorite. (3) Co-rich Mn nodules are composed of romanechite and todorokite laminae. Mn-rich layers (up to 58% MnO) contain up to 1.8% Co. (4) Goethite nodules with Fe up to 67% Fe2O3 have low Mn and trace metals. We interpret this mineralization paragenesis to be related to major changes in oceanographic and tectonic regimes. Three phosphatization generations formed hardgrounds dated by 87Sr/86Sr isotopes as late Oligocene, early Miocene, and latest early Miocene. During the latest early Miocene, the hardground was fractured and breached due to regional intraplate tectonism, which was coeval with a widespread regional erosional unconformity. The stratabound layers and Co-rich manganese nodules were derived from low-temperature geothermally driven hydrothermal fluids, with fluid conduits along reactivated faults. During middle and late Miocene, the introduction of vigorous deep water flow from the Arctic generated growth of hydrogenetic ferromanganese crusts. Finally, growth of diagenetic Fe-rich nodules (late Pliocene) was promoted by the introduction of hypersaline Mediterranean Outflow Water into the Atlantic Ocean.Instituto Geológico y Minero de España, EspañaEstación de Bioloxía Mariña da Graña, Universidade de Santiago de Compostela, Españ

The demo water-cooled lead–lithium breeding blanket: Design status at the end of the pre-conceptual design phase

The Water-Cooled Lead–Lithium Breeding Blanket (WCLL BB) is one of the two blanket concept candidates to become the driver blanket of the EU-DEMO reactor. The design was enacted with a holistic approach. The influence that neutronics, thermal-hydraulics (TH), thermo-mechanics (TM) and magneto-hydro-dynamics (MHD) may have on the design were considered at the same time. This new approach allowed for the design team to create a WCLL BB layout that is able to comply with different foreseen requirements in terms of integration, tritium self-sufficiency, and TH and TM needs. In this paper, the rationale behind the design choices and the main characteristics of the WCLL BB needed for the EU-DEMO are reported and discussed. Finally, the main achievements reached during the pre-conceptual design phase and some remaining open issues to be further investigated in the upcoming conceptual design phase are reported as well

Integrated design of breeding blanket and ancillary systems related to the use of helium or water as a coolant and impact on the overall plant design

Currently, for the EU DEMO, two Breeding Blankets (BBs) have been selected as potential candidates for the integration in the reactor. They are the Water Cooled Lithium Lead and the Helium Cooled Pebble Bed BB concepts. The two BB variants together with the associated ancillary systems drive the design of the overall plant. Therefore, a holistic investigation of integration issues derived by the BB and the installation of its ancillary systems has been performed. The issues related to the water activation due to the 16N and 17N isotopes and the impact on the primary heat transfer systems have been investigated providing guidelines and dedicated solution for the integration of safety devices as isolation valves. The tritium retention and the permeation rates through the blanket and its ancillary systems have been also assessed taking into account different operating points both for the BB and ancillaries and comparing, when possible, the releases with the operating and safety limits. Moreover, the issues related to the tritium start-up inventory as well as the uncertainties on the Tritium Breeding Ratio (TBR) due to the integration of the auxiliary systems within the Vacuum Vessel have been also studied. Finally, the impact of the BB concepts on the safety systems like the Vacuum Vessel Pressure Suppression System is described with a particular focus on the different measures that should be implemented according to the considered concept. All these aspects are then taken into account to drive future developments during the Concept Design Phase

Integrated design of breeding blanket and ancillary systems related to the use of helium or water as a coolant and impact on the overall plant design

Currently, for the EU DEMO, two Breeding Blankets (BBs) have been selected as potential candidates for the integration in the reactor. They are the Water Cooled Lithium Lead and the Helium Cooled Pebble Bed BB concepts. The two BB variants together with the associated ancillary systems drive the design of the overall plant. Therefore, a holistic investigation of integration issues derived by the BB and the installation of its ancillary systems has been performed. The issues related to the water activation due to the 16N and 17N isotopes and the impact on the primary heat transfer systems have been investigated providing guidelines and dedicated solution for the integration of safety devices as isolation valves. The tritium retention and the permeation rates through the blanket and its ancillary systems have been also assessed taking into account different operating points both for the BB and ancillaries and comparing, when possible, the releases with the operating and safety limits. Moreover, the issues related to the tritium start-up inventory as well as the uncertainties on the Tritium Breeding Ratio (TBR) due to the integration of the auxiliary systems within the Vacuum Vessel have been also studied. Finally, the impact of the BB concepts on the safety systems like the Vacuum Vessel Pressure Suppression System is described with a particular focus on the different measures that should be implemented according to the considered concept. All these aspects are then taken into account to drive future developments during the Concept Design Phase.peer-reviewe