DEMO port plug design and integration studies

Abstract

The EUROfusion Consortium established in 2014 and composed by European Fusion Laboratories, and in particular the Power Plant Physics and Technology department aims to develop a conceptual design for the Fusion DEMOnstration Power Plant, DEMO. With respect to present experimental machines and ITER, the main goals of DEMO are to produce electricity continuously for a period of about 2 hours, with a net electrical power output of a few hundreds of MW, and to allow Tritium self-sufficient breeding with an adequately high margin in order to guarantee its planned operational schedule, including all planned maintenance intervals. This will eliminate the need to import tritium fuel from external sources during operations. In order to achieve these goals, extensive engineering efforts as well as physics studies are required to develop a design that can ensure a high level of plant reliability and availability. In particular, interfaces between systems must be addressed at a very early phase of the project, in order to proceed consistently. In this paper we present a preliminary design and integration study, based on physics assessments for the EU DEMO1 Baseline 2015 with an Aspect Ratio of 3.1 and 18 Toroidal Field Coils, for the DEMO port plugs. These aim to host systems like Electron Cyclotron Heating launchers currently developed within the Work Package Heating and Current Drive that need an external radial access to the plasma and through in-vessel systems like the breeder blanket. A similar approach shown here could be in principle followed by other systems, e.g. other heating and current drive systems or diagnostics. The work addresses the interfaces between the port plug and the blanket considering the Helium-Cooled Pebble Bed and the Water Cooled Lithium Lead which are two of four breeding blanket concepts under investigation in Europe within the Power Plant Physics and Technology Programme: the required openings will be evaluated in terms of their impact onto the blanket segments thermo-mechanical and nuclear design considering mechanical integration aspects but also their impact on Tritium Breeding Ratio. Since DEMO is still in a pre-conceptual phase, the same methodology is applicable to the other two blanket concepts, as well.

Initial port integration concept for EC and NB systems in EU DEMO tokamak

“…The integration for the two systems EC and NB is an ongoing process [10]- [12] and is supported by functional analyses. For further details on the methodology for the HCD interface and requirements analysis, a systems architecture model was established [13].…”

“…The conceptual design of the systems including sub-systems are described elsewhere cf. for EC [6][10] [12], for NB [14] [15]. Fig.…”

Review of the Innovative H&CD Designs and the Impact of Their Configurations on the Performance of the EU DEMO Fusion Power Plant Reactor

“…DEFINITION OF DEMO (PLANT) LAYOUT Taking into account the lessons learned from ITER EC [20] a similar approach as for NB was done for the EC system. A number of physics studies (not discussed here) were conducted together with conceptual layout studies [21], [22]. Also different options for the configurations were investigated [23].…”

Interface and requirements analysis on the DEMO Heating and Current Drive system using Systems Engineering methodologies

“…Presently, three different heating methods are considered, i.e. Electron Cyclotron Heating (ECH) [6][7], Ion Cyclotron Heating (ICH) [8] and Neutral Beam Injection (NBI) [9][10]. The HCD system must be fully integrated into DEMO, for which two main concepts are currently considered: i) a DEMO 1 concept based on the expected performances of ITER with an improved technology; ii) an "optimistic design" (Flexi-DEMO), capable to be operated as steady-state.…”