Towards an Assessment of Alternative Divertor Solutions for DEMO
Event details
| Date | 06.05.2015 |
| Hour | 10:30 › 11:30 |
| Speaker | Dr. Holger Reimerdes, EPFL-CRPP, for the WPDTT1 EUROfusion project |
| Location |
PPB 019
|
| Category | Conferences - Seminars |
To mitigate the risk that the conventional divertor solution adopted for ITER, which is based on a single-null magnetic configuration and tungsten (W) targets, will not extrapolate to a fusion power plant, the European fusion consortium (EUROfusion) is assessing alternative divertor solutions. Considered alternatives include non-conventional configurations and the use of liquid metals (LMs) as divertor armour. Their performance and costs will be compared to those of a conservative DEMO design targeting 500 MW of electric power with a major radius of 9 m, a toroidal field of 5.8 T and a plasma current of 20 MA.
The assessment of alternative configurations considers the snowflake divertor (SFD), the X divertor (XD) and the Super-X divertor (SXD). DEMO prototypes of these configurations have been developed and are now optimised to minimise the required PF coil mass, the volume enclosed by the TF coils, the forces between coils and the fraction of neutrons lost for breeding. Any increase of these costs over the reference solution is weighed against predictions of the performance improvement with regard to access to and stability of operation in the detached regime and any increase of the power that can be radiated in the divertor using state-of-the-art boundary models. The assessment of LM based divertor solutions focuses on a heat conduction based capillary porous system (CPS), which is viewed as the least complex LM based solution. While the heat exhaust potential of such a solution faces similar challenges as W targets, key advantages are the in-situ repair of eroded material and potentially a greater tolerance for transient heat flux excursions. Materials considered are lithium (Li), tin (Sn) or Li/Sn alloys and the assessment includes a demonstration of a CPS solution including cooling and replenishment in the FTU tokamak.
Upon conclusion the assessment should identify any gaps that must be addressed before considering an alternative divertor solution for DEMO.
The assessment of alternative configurations considers the snowflake divertor (SFD), the X divertor (XD) and the Super-X divertor (SXD). DEMO prototypes of these configurations have been developed and are now optimised to minimise the required PF coil mass, the volume enclosed by the TF coils, the forces between coils and the fraction of neutrons lost for breeding. Any increase of these costs over the reference solution is weighed against predictions of the performance improvement with regard to access to and stability of operation in the detached regime and any increase of the power that can be radiated in the divertor using state-of-the-art boundary models. The assessment of LM based divertor solutions focuses on a heat conduction based capillary porous system (CPS), which is viewed as the least complex LM based solution. While the heat exhaust potential of such a solution faces similar challenges as W targets, key advantages are the in-situ repair of eroded material and potentially a greater tolerance for transient heat flux excursions. Materials considered are lithium (Li), tin (Sn) or Li/Sn alloys and the assessment includes a demonstration of a CPS solution including cooling and replenishment in the FTU tokamak.
Upon conclusion the assessment should identify any gaps that must be addressed before considering an alternative divertor solution for DEMO.
Practical information
- Informed public
- Free
Organizer
- Prof. P. Ricci
Contact
- Prof. P. Ricci