Feasibility study of fast swept divertor strike point suppressing transient heat fluxes in big tokamaks.

0481373 - ÚFP 2018 RIV CH eng J - Článek v odborném periodiku
Horáček, Jan - Cunningham, G. - Entler, Slavomír - Dobias, P. - Duban, R. - Imríšek, Martin - Markovič, Tomáš - Havlíček, Josef - Enikeev, R.
Feasibility study of fast swept divertor strike point suppressing transient heat fluxes in big tokamaks.
Fusion Engineering and Design. Roč. 123, November (2017), s. 646-649. ISSN 0920-3796. E-ISSN 1873-7196.
[SOFT 2016: Symposium on Fusion Technology /29./. Prague, 05.09.2016-09.09.2016]
Grant CEP: GA ČR(CZ) GA16-14228S; GA MŠMT(CZ) LM2015045; GA MŠMT(CZ) 8D15001; GA MŠMT LG14002
Institucionální podpora: RVO:61389021
Klíčová slova: DEMO * ELM * Divertor * Heat flux * Tokamak
Obor OECD: Nuclear related engineering
Impakt faktor: 1.437, rok: 2017
http://www.sciencedirect.com/science/article/pii/S0920379617300376

n order to avoid metal surface melting of divertor targets of big tokamak fusion reactors by localized ELM heat loads, sudden detachment loss or VDEs, we study a new technique of spreading the heat flux by harmonic divertor strike point sweeping using a dedicated divertor coil. We ran 2D dynamic heat conduction simulation using real infra-red data of large ELMs heat fluxes on JET divertor target, rescaled for EU DEMO reactor (B-0 = 6 T, I-p =21 MA, R-0 = 9 m). Aiming for the surface temperature suppression factor of 4, this requires sweeping with amplitude*frequency=7cm*2 kHz. Building the divertor coil out of 27 tons of copper, this requires 0.8 MW cooling. Triggered by analog divertor heat flux signal, dedicated dynamic Fiesta simulation scenario requires 54 capacitive energy storages at 1500 V (6mF) discharged into 54 divertor coils, each with AC current of 130kA for each ELM event for similar to 4 ms (with waiting time 40 ms). The Ix B-tor forces would yield less than 0.1 mm rotational vibrations of the coil at the ELM frequency (similar to 20 Hz). The DEMO divertor surface temperature suppression reaches factor of 9 with 18 kV, 20 cm, 7.5 kHz, 400 kA. We also calculate system requirements (0.6mF, 5 kV & 60kA -> suppression factor = 2) for ASDEX Upgrade using the upper divertor coil. Since we found no show-stoppers, this technique seems attractive for big tokamaks.
Trvalý link: http://hdl.handle.net/11104/0276956