Effect of high-flux H/He plasma exposure on tungsten damage due to transient heat loads

0444972 - ÚFP 2016 RIV NL eng J - Článek v odborném periodiku
De Temmerman, G. - Morgan, T.W. - van Eden, G.G. - de Kruif, T. - Wirtz, M. - Matějíček, Jiří - Chráska, Tomáš - Pitts, R.A. - Wright, G.M.
Effect of high-flux H/He plasma exposure on tungsten damage due to transient heat loads.
Journal of Nuclear Materials. Roč. 463, August (2015), s. 198-201. ISSN 0022-3115. E-ISSN 1873-4820.
[PLASMA-SURFACE INTERACTIONS 21: International Conference on Plasma-Surface Interactions in Controlled Fusion Devices. Kanazawa, 26.05.2014-30.05.2014]
Grant CEP: GA ČR(CZ) GA14-12837S
Institucionální podpora: RVO:61389021
Klíčová slova: plasma-facing components * tungsten * hydrogen * helium * ELM
Obor OECD: Nuclear related engineering
Impakt faktor: 2.199, rok: 2015
http://www.sciencedirect.com/science/article/pii/S0022311514006758#

The thermal shock behaviour of tungsten exposed to high-flux plasma is studied using a high-power laser. The cases of laser-only, sequential laser and hydrogen (H) plasma and simultaneous laser plus H plasma exposure are studied. H plasma exposure leads to an embrittlement of the material and the appearance of a crack network originating from the centre of the laser spot. Under simultaneous loading, significant surface melting is observed. In general, H plasma exposure lowers the heat flux parameter (FHF) for the onset of surface melting by _25%. In the case of He-modified (fuzzy) surfaces, strong surface deformations are observed already after 1000 laser pulses at moderate FHF = 19MJ m_2 s_1/2, and a dense network of fine cracks is observed. These results indicate that high-fluence ITER-like plasma exposure influences the thermal shock properties of tungsten, lowering the permissible transient energy density beyond which macroscopic surface modifications begin to occur.
Trvalý link: http://hdl.handle.net/11104/0247402