29th Symposium on Fusion Technology (SOFT 2016)

P1.112 Effect of engineering constraints on charged particle wall heat loads in DEMO

5 Sep 2016, 14:20

1h 40m

Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Board: 112

Poster F. Plasma Facing Components P1 Poster session

Speaker

Francesco Maviglia (Power Plant Physics & Technology Department)

Description

The design of the demonstration fusion reactor DEMO presents challenges beyond those faced by the ITER project and may require the implementation of different solutions. One of the biggest challenges is managing the heat flux to the main chamber wall. The presently predicted total heating power in DEMO is more than 3 times that predicted for ITER value, while the major radius is only 1.5 times greater. Furthermore the present DEMO technological wall heat load limitation is limited to ~1MW/m²2, due to structural material limitations and the tritium breeding requirements, while the ITER first wall is designed for values up to 4.7MW/m²2. This paper focuses on the evaluation of the effect of the engineering constraints on the charged particle heat load. First, a series of optimizations on the plasma and first wall 2D shape is presented. A subset of the resulting configurations was analysed using the 3D field line tracing code PFCflux, to derive the heat flux on to a 3D engineering model of the first wall. Finally a sensitivity scan was performed on the main wall design geometrical parameters and on manufacturing and installation tolerances. The resulting heat flux peaking factors were up to a factor ~10 leading to a value of the heat flux on the wall up to 10MW/m²2. While some optimization can be reached with detailed shaping of the components, this is in line with extrapolation from the ITER values. These technological limitations of DEMO, i.e. the ~1MW/m²2 limit, may push towards the adoption of discrete high heat flux limiters, with the implications on their remote maintainability and the breeding capability to be analyzed. The developed methodology will be used to efficiently include and prescribe the manufacturing and installation tolerances for the DEMO components as they become available.