Calculation of the electromagnetic forces in the blanket of a tokamak reactor during plasma current disruption and determination of the consequent mechanical stresses
A program system has been developed for the calculation of mechanical effects caused by disruptions in tokamak reactors. This system uses a properly modified version of the three dimensional computer code CARIDDI to calculate eddy currents and Lorentz forces. The derived stresses are calculated with the ABAQUS program. A comparison with experimental data, taken from a scale model of the ASDEX tokamak vacuum vessel, is presented. This shows a good agreement between the measured and calculated results. Several calculations are performed for the Karlsruhe helium cooled ceramic breeder blanket for NET/ITER. Two disruptions are considered. The first assumes a decrease of the plasma current from 11 MA to zero in 20 ms, while the second assumes first a plasma displacement in vertical direction of 1.5m in 40ms and, subsequently, a decrease of the plasma current to zero in 20 ms. Where appropriate, the magnetic damping is taken into account, as well as the presence of a "saddle loop". Various kinds of blanket supports to the surrounding structures are considered. Static and dynamic stress analyses are performed. In many of the cases, especially in the ones with plasma displacement, the stresses in the blanket box are above the maximum stresses allowed by the ASME norms. The calculated stresses in the canisters are, however, acceptable.
Bibliographic Reference: EUR 11399 DE (1990) KfK 4757, 173 pp., MF, ECU 8
ISBN: ISSN 0303-4003
Record Number: 199110001 / Last updated on: 1994-12-02
Original language: de
Available languages: de