Tokamak active laser pyrometry for tungsten deposited layer characterisation

• Published in: Fusion engineering and design 2012-03, Vol.87 (3), p.267-274
• Main Authors: Semerok, A., Jaubert, F., Fomichev, S.V., Thro, P.-Y., Grisolia, C.
• Format: Article
• Language: English
• Subjects: Active laser pyrometry; Computer simulation; Deposited tungsten layer; Deposition; Heating; Laser heating; Lasers; Layer characterisation; Plasma-facing components; Pyrometry; Repetition; Surface chemistry; Tokamak; Tokamak devices
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2011.12.021

In modern fusion reactors, the erosion of plasma facing surface results in layers deposition on tokamak “cold” surfaces. To provide efficient operation of tokamaks, it is essential to characterise the deposited layer with high tritium content. In situ rapid surface characterisation without reactor components disassembly is required. Active laser pyrometry together with a repetition rate Nd–YAG laser (1Hz–1kHz repetition rate frequency) applied for surface heating can be used to characterise some thermo-physical properties (thermal capacity, thermal contact, and conductivity) of a micrometric layer. The pyrometer system was developed and applied to characterise some properties of a W-layer (140μm) on a CFC-substrate. The numerical code developed for 3-D simulation of LH of a surface with the deposited layer was applied to simulate the experimental heating temperatures. The experimental and simulation results were compared. W-layer characterisation was performed by fitting the experimental and theoretical heating temperatures.