Tritium Removal by Laser Heating and Its Application to Tokamaks
Authors: C.H. Skinner, C.A. Gentile, G. Guttadora, A. Carpe, S. Langish, K.M. Young, M. Nishi, and W. Shu
Date of PPPL Report: November 2001
Date of Revised PPPL Report: December 2001
Presented at: the 6th International Conference on Tritium Science and Technology held in Tsukuba, Japan, on November 11-16, 2001. Submitted to Fusion Science and Technology.
A novel laser heating technique has recently been applied to removing tritium from carbon tiles that had been exposed to deuterium-tritium (DT) plasmas in the Tokamak Test Fusion Reactor (TFTR). A continuous wave neodymium laser, of power up to 300 watts, was used to heat the surface of the tiles. The beam was focussed to an intensity, typically 8 kW/cm2, and rapidly scanned over the tile surface by galvanometer-driven scanning mirrors. Under the laser irradiation, the surface temperature increased dramatically, and temperatures up to 2,300 °C were recorded by an optical pyrometer. Tritium was released and circulated in a closed-loop system to an ionization chamber that measured the tritium concentration. Most of the tritium (up to 84%) could be released by the laser scan. This technique appears promising for tritium removal in a next-step DT device as it avoids oxidation, the associated deconditioning of the plasma facing surfaces, and the expense of processing large quantities of tritium oxide. Some engineering aspects of the implementation of this method in a next-step fusion device will be discussed.