Hydrogen-loading is a powerful method to protect optical fibres against darkening in a large range of irradiation conditions . Taking into account that all the irradiation tests are accelerated, i.e. involving high dose-rate conditions, and knowing that high dose-rates induce more RIA degradation in the fibres, we can infer that all our radiation tests are conservative and that hydrogen-loaded fibres can withstand the ITER radiation field to a large extent. The major difficulty is now in the technological fabrication of hydrogenated large-core fibre bundles. Such fabrication has not been demonstrated yet.
Endlessly ultimate radiation resistance in fibres could be thinkable by feeding the fibres constantly with a small amount of hydrogen. The approach could be envisaged using microstructured fibres containing air holes (porous medium) enhancing greatly and in-situ the hydrogen diffusion. Such an idea was demonstrated in a short BR2 irradiation test and already reported in the EFDA documentation.
|Number of pages
|Published - Oct 2010
|Studiecentrum voor Kernenergie