Laser ablation and heating tests performed on TORE SUPRA and TEXTOR graphite samples

In D-T fusion reactors, tritium is trapped in the co-deposited layer which results from the sputtering of the surface of plasma facing components (C, Be, stainless steel) by plasma during reactor operation. Re-deposition of the sputtered particles together with hydrogen, deuterium and tritium takes place on colder areas inside the vessel. The amount of tritium trapped in that layer could threaten ITER operation. Therefore various detritiation processes are under evaluation. Among those, ablation by nanosecond pulsed lasers has already been used as a cleaning process for different applications such as grease, paint and nuclear decontamination removal. We are developing a program in order to study the efficiency of a possible laser-based detritiation process using such lasers. A first part of our work has consisted in implementing laser benches able to operate with infra-red (1064 nm), visible (532 nm) and ultra-violet (355 nm) wavelengths, and allowing us to well characterise the laser fluence on the sample. Then, laser ablation and heating experiments have been performed on TORE-SUPRA and TEXTOR graphite samples with codeposition layer.