29th Symposium on Fusion Technology (SOFT 2016)

P1.090 Mechanical pre-dimensioning and pre-optimization of tokamaks’ toroidal coils featuring a winding pack layout

5 Sep 2016, 14:20

1h 40m

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

Board: 90

Poster E. Magnets and Power Supplies P1 Poster session

Speaker

Anatoly Panin (Forschungszentrum Juelich GmbH)

Description

Successful operation of Demonstration Reactors is a key step in the fusion development. The structural integrity of the superconducting magnets producing high magnetic fields that are crucial for optimization of a fusion reactor performance must be ensured. Combinations of calculation approaches, reasonable modelling simplifications and clever prioritization at each analysis phase facilitate design optimization by relatively simple and “inexpensive” calculation tools. The mechanical pre-dimensioning of the magnets is extremely useful at an early design stage, prior to the numerical analysis. A calculation tool that reasonably estimates the me­chanical strength of the structural components of the toroidal field coil (TFC) system under the dominating electromagnetic forces is described. The novelty of the approach is that it deals not only with the coil casing strength in the critical location but also treats the winding pack wound with the cabled conductor in detail under an essentially 3D stress state. The semi-analytical procedure features optimization of the layered windings by grading the radial and toroidal walls of the conductor jacket separately. The minimum space required for the coil casing and for the winding mechanical structures is defined basing on the strength properties of the pre-selected structural steels. The procedure has been already successfully benchmarked against the numerical solutions for several tentative TFC designs for the European DEMO project. Since the coils pre-dimensioning is limited to the most stressed coil inboard portion, the next analysis step is the 3D FE modelling featuring the homogenized winding. Reasonably simplified and good parametrized numerical models facilitate the sensitivity study and deliver numerical results transparent for the physical interpretation. The detailed “express” conductor analysis based on the calculated averaged winding stresses is attributed to this analysis stage. Critical winding locations are found as the worst combinations of conductor stress components. Examples from a current fusion project are given.