American Nuclear Society

Home / Publications / Journals / Fusion Science and Technology / Volume 50 / Number 1 / Pages 76-83

Burn Control Study Using Burning Plasma Simulation Experiments in JT-60U

H. Takenaga, Y. Miura, H. Kubo, Y. Sakamoto, H. Hiratsuka, H. Ichige, I. Yonekawa, Y. Kawamata, S. Tsuiji-Iio, R. Sakamoto, S. Kobayashi

Fusion Science and Technology / Volume 50 / Number 1 / July 2006 / Pages 76-83

Technical Paper

Burning plasma simulation experiments were performed for burn control study on ELMy H-/L-mode plasmas and reversed shear (RS) plasmas with an internal transport barrier in JT-60U. In a burning plasma simulation scheme, two neutral beam (NB) groups were used: one that simulates alpha-particle heating and another that simulates external heating. For the alpha-particle heating simulation, the heating power proportional to the deuterium-deuterium (D-D) neutron yield rate was injected. The behavior of the part of the NB heating simulating alpha-particle heating was varied by increasing the proportional gain relating the applied power to the measured neutron yield rate in both ELMy H-mode and RS plasmas, while the part of the NB power in the role of external heating was held constant i.e., no-burn-control case. Above a certain value of the proportional gain, a runaway effect was triggered where excursive increases in the neutron yield rate and stored energy were observed. With burn control, where the stored energy was controlled at a constant value by a feedback control system using the external heating, the runaway was not triggered, and the neutron yield rate was kept at a constant value in the L-mode plasmas. Zero-dimensional calculation indicated that the runaway triggered by increasing the proportional gain well simulates the runaway triggered by improved confinement. The limitations came from differences between deuterium-tritium and D-D plasmas, such as the dominant reaction for the neutron yield and the temperature dependence of the fusion reaction rate, which were discussed together with improvement on the burning plasma simulation scheme.

Questions or comments about the site? Contact the ANS Webmaster.