Speaker
Filip Janky
(Max Planck Institute for Plasma Physics)
Description
DEMO is aproposed demonstration fusion power plant which is under design. Fusion power, Pfus, has to be controlled at certain level to produce sufficient net electricity. However, this increases power through separatrix, Psep, and thus can produce excessive heat flux to the divertor which can lead to damage. Due to neutron radiation, the materials are even more susceptible to damage for a given heat flux than in non-reactor devices. One way to protect the divertor is seeding plasma impurities to radiate the energy in the scrape-off layer and in the divertor region before it hits the divertor target plates.
The aim of this work is to simulate feedback control of Pfus and Psep, and to find a way to decouple Pfus from Psep. Fusion power is controlled either via plasma density using pellet frequency or via changing the ratio of deuterium and tritium in the injected pellets. To prevent increasing Psep and heat load on the divertor while increasing Pfus a xenon gas can be puffed into the main chamber. However, Psep has to be kept above a threshold to stay in H-mode. Therefore, feedback control of the xenon gas puff into the divertor is modelled. Possible methods of keeping Psep fixed while optimising Pfus are presented here.
A model of DEMO has been implemented in ASTRA. ASTRA is a transport code for fusion devices equipped with equilibrium, transport, fuelling, heating and current drive modules. To model the combination with feedback control loops, ASTRA was coupled with Simulink. Simulink is a powerful tool to model and to simulate different dynamic systems. It allows fast and simple development of controllers using its built-in blocks. Therefore, coupling of ASTRA with Simulink gives the advantage of fast development of controllers for the power plant modelled with sophisticated physics based on the transport codes.
Co-authors
Christopher J. Rapson
(Max Planck Institute for Plasma Physics, Garching, Germany)
Emiliano Fable
(Max Planck Institute for Plasma Physics, Garching, Germany)
Filip Janky
(Max Planck Institute for Plasma Physics, Garching, Germany)
Hartmut Zohm
(Max Planck Institute for Plasma Physics, Garching, Germany)
Wolfgang Treutterer
(Max Planck Institute for Plasma Physics, Garching, Germany)
