Application of Pulsed Laser Light for the Removal of Co-deposited Deuterium/Tritium from In-vessel Components
Various methods were investigated and tested for removal of the co-deposited tritium from the in-vessel components of fusion machines. Among other, two methods of laser-induced removal of tritium trapped in the co-deposits is under investigation. The first variant – thermal laser desorption is aimed for some tritium release without the co-deposited layer removal; the second – laser ablation is used for removal of the whole containing tritium co-deposited layer. In the Institute of Plasma Physics and Laser Microfusion there have been prepared experiments on removal of deuterium from tokamak in-vessel components using laser-induced thermal desorption and ablation methods.
In the paper, the experimental methods, apparatus and results of measurements on deuterium removal are presented. The investigations were carried out using Nd:YAG 3.5-ns laser pulse with energy up to 0,8 J at 1060 nm wavelength, or up to 0,4 J at 530 nm, or up to 0,3 J at 350 nm at 10 Hz repetition rate. Determination of the characteristics of ions emitted from the laser-illuminated targets was performed with the use of ion collectors and an electrostatic ion-energy analyzer. As sample targets some pure graphite slabs and deuterium contaminated tiles from the TEXTOR were exploited. There were some energy density levels of laser radiation and opto-mechanical setups for feasible desorption and ablation methods investigated.
A novel detritation method using laser-generated x-rays for thermal desorption of tritium from the in-vessel components was analysed.
The recent investigation of thermonuclear engineering prove that the crucial issue for a tokamak operation is an effective tritium removal from in-vessel components of the fusion reactor . Tritium is trapped in the co-deposited layer, which results from deposition of a material sputtered from the plasma facing components . The process is particularly important in case of the divertor/limiter for which the rate of the co-deposited layer grown is highest.
Various methods were investigated and tested for removal of the co-deposited tritium from the in-vessel components of fusion machines. Among other, two methods of laser-induced removal of tritium trapped in the co-deposits is under investigation. The first variant – thermal laser desorption is aimed for some tritium release without the co-deposited layer removal; the second – laser ablation is used for removal of the whole containing tritium co-deposited layer. In the Institute of Plasma Physics and Laser Microfusion there have been prepared experiments on removal of deuterium from tokamak in-vessel components using laser-induced thermal desorption and ablation methods.
In the paper, the experimental methods, apparatus and results of measurements on deuterium removal are presented. The investigations were carried out using Nd:YAG 3.5-ns laser pulse with energy up to 0,8 J at 1,06 m wavelength, or up to 0,4 J at 0,53 m, or up to 0,3 J at 0.35 m at 10 Hz repetition rate. Determination of the characteristics of ions emitted from the laser-illuminated targets was performed with the use of ion collectors and an electrostatic ion-energy analyzer. As sample targets some pure graphite slabs and deuterium contaminated tiles from the TEXTOR were exploited. There were some energy density levels of laser radiation and opto-mechanical setups for feasible desorption and ablation methods investigated.
A novel detritation method using laser-generated x-rays for thermal desorption of tritium from the in-vessel components was analysed.
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