Effect of two-stage shattered pellet injection on tokamak disruptions

Nuclear Fushion

article

O. Vallhagen¹  I. Pusztai¹  M. Hoppe¹  S.L. Newton³  T. Fülöp¹ 

[1] Department of Physics, Chalmers University of Technology;Ecole Polytechnique Fédérale de Lausanne ,(EPFL), Swiss Plasma Center;Culham Centre for Fusion Energy

关键词: disruption mitigation;    shattered pellet injection;    runaway electron;    plasmasimulation;    ITER;   

DOI  :  10.1088/1741-4326/ac667e

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

An effective disruption mitigation system in a tokamak reactor should limit the exposure of the wall to localized heat losses and to the impact of high current runaway electron beams, and avoid excessive forces on the structure. We evaluate with respect to these aspects a two-stage deuterium–neon shattered pellet injection in an ITER-like plasma, using simulations with the DREAM framework (Hoppeet al2021Comput. Phys. Commun.268108098). To minimize the obtained runaway currents an optimal range of injected deuterium quantities is found. This range is sensitive to the opacity of the plasma to Lyman radiation, which affects the ionization degree of deuterium, and thus avalanche runaway generation. The two-stage injection scheme, where dilution cooling is produced by deuterium before a radiative thermal quench caused by neon, reduces both the hot-tail seed and the localized transported heat load on the wall. However, during nuclear operation, additional runaway seed sources from the activated wall and tritium make it difficult to reach tolerably low runaway currents.

【 授权许可】

Unknown