“…In the 2015 baseline design [1], the EU DEMO tokamak is subdivided in 18 identical sectors in the toroidal direction; each sector contains three outboard (OB) and two inboard (IB) BB segments. Four possible BB concepts are being explored: the aforementioned HCPB (object of this study and responsibility of KIT, Germany) and WCLL (responsibility of ENEA, Italy), plus the Helium-Cooled Lithium-Lead (responsibility of CEA, France) [10] and the Dual-Cooled Lithium-Lead (responsibility of CIEMAT, Spain) [11].…”
The GEneral Tokamak THErmal-hydraulic Model -GETTHEM has been updated to the most recent version of the EU DEMO Helium-Cooled Pebble Bed (HCPB) Breeding Blanket (BB) design. The GETTHEM results are first benchmarked in a controlled case against the results of 3D Computational Fluid-Dynamics computations, showing an acceptable accuracy despite the inherent simplifications in the GETTHEM model. GETTHEM is then applied to the evaluation of the poloidal hot-spot temperature distribution in an entire BB segment, showing that the maximum temperature in the EUROFER structures overcomes the design limit of 550 °C by more than 50 °C in some Blanket Modules. A possible mitigation strategy is then proposed and analyzed, based on the idea of cooling the First Wall in parallel with the breeding zone, showing that this solution would allow having the EUROFER in its working temperature range in the entire segment, although at the expense of a larger pressure drop.
“…In the 2015 baseline design [1], the EU DEMO tokamak is subdivided in 18 identical sectors in the toroidal direction; each sector contains three outboard (OB) and two inboard (IB) BB segments. Four possible BB concepts are being explored: the aforementioned HCPB (object of this study and responsibility of KIT, Germany) and WCLL (responsibility of ENEA, Italy), plus the Helium-Cooled Lithium-Lead (responsibility of CEA, France) [10] and the Dual-Cooled Lithium-Lead (responsibility of CIEMAT, Spain) [11].…”
The GEneral Tokamak THErmal-hydraulic Model -GETTHEM has been updated to the most recent version of the EU DEMO Helium-Cooled Pebble Bed (HCPB) Breeding Blanket (BB) design. The GETTHEM results are first benchmarked in a controlled case against the results of 3D Computational Fluid-Dynamics computations, showing an acceptable accuracy despite the inherent simplifications in the GETTHEM model. GETTHEM is then applied to the evaluation of the poloidal hot-spot temperature distribution in an entire BB segment, showing that the maximum temperature in the EUROFER structures overcomes the design limit of 550 °C by more than 50 °C in some Blanket Modules. A possible mitigation strategy is then proposed and analyzed, based on the idea of cooling the First Wall in parallel with the breeding zone, showing that this solution would allow having the EUROFER in its working temperature range in the entire segment, although at the expense of a larger pressure drop.
“…Along the 1 st phase of the project 2 different versions of the DCLL model, based on DEMO2014, have been developed in order to achieve the best behavior in terms of nuclear responses but also taking into account mechanical, manufacturing and chemical aspects. Starting from a version [5] [6] in which 64 cm of breeder were used in the OB region, the next step was increasing it to 69 cm [8] [9]. At the same time other changes ( Fig.…”
Section: First Phase: Demo2014 Dcll Improvement and Primary Neutronicmentioning
The research study focuses on the neutronic design analysis and optimization of one of the options for a fusion reactor designed as DCLL (dual coolant lithium-lead). The main objective has been to develop an efficient and technologically viable modular DCLL blanket using the DEMO generic design specifications established within the EUROfusion Programme. The final neutronic design has to attend the requirements of: tritium self-sufficiency; BB thermal efficiency; preservation of plasma confinement; temperature limits imposed by the materials; and radiation limits to guarantee the largest operational life for all the components. Therefore, a 3D fully heterogeneous DCLL neutronic design has been developed for the DEMO baseline 2014 determining its behaviour under the real operational conditions of the DEMO reactor. Consequent actions have been adopted to improve its performances. Neutronic assessments have specially addressed the Tritium Breeding Ratio, Multiplication Energy Factor, power density distributions, damage and shielding responses. The model has been then adapted to the subsequent DEMO baseline 2015 (with a more powerful and bigger plasma, smaller divertor and bigger blanket segments), implying new design choices to improve the reactor nuclear performances.
“…10 can also be seen as a degenerate form of bubbly flow where helium films are being formed close to the walls. In the same figure, case (24) shows an intermittency between slug and bubbly flow along the duct length. Also cases ( 25) and ( 26) present attributes of both slug and bubbly flows.…”
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