29th Symposium on Fusion Technology (SOFT 2016)

O2B.1 Plasma facing components for the European DEMO: advances in engineering designs

6 Sep 2016, 11:00

20m

Meeting Hall I 1st floor (Prague Congress Centre)

Board: 1

Oral F. Plasma Facing Components O2B

Speaker

Thomas R. Barrett (CCFE)

Description

The conceptual design of the European DEMO power reactor is under development as part of the EUROfusion Consortium. DEMO is a high fusion power, long-pulsed, tritium self-sufficient device, and hence amongst the most critical and high-risk technologies are the divertor and main chamber plasma-facing components (PFCs). These PFCs must operate reliably under an extreme surface heat and particle flux while surviving intense neutron radiation, and must also allow sufficient high energy neutron transmission to the tritium breeding blankets. In addition, a preliminary assessment of wall surface loads (and their uncertainty) has led to the anticipated requirement for high heat flux PFCs in certain regions of the main chamber wall, perhaps embodied as discretely placed limiters. Such challenging requirements and conditions have necessitated wide engineering design exploration studies, and these have started to yield promising PFC designs. In this paper, we present engineering concepts of divertor and first wall PFCs which, compared to baseline designs, are intended to improve power handling or extend operational life. Design by analysis is used routinely with the objective of reducing stress in the structure, the tungsten armour, and/or the interface between these materials. A number of designs are featured here. An update is given on the Thermal Break divertor PFC design, including results of fabrication trials and high heat flux mock-up manufacturing. A discrete limiter PFC is outlined, which makes use of the thermal inertia of tungsten to improve power handling for short durations. Progress is reported with the de-coupled first wall ‘finger’ and monoblock PFC designs. The potential and limits of each design are reviewed and the outlook for future work is described.