View full image picture of dismantling the waveguides for the microwave diagnostics

Dismantling the waveguides for the microwave diagnostics known as KG3 and KG8

Week 14: Waveguides and divertor plates removed

As part of the ongoing programme to exchange windows on some of the diagnostic systems, it has been necessary to remove waveguides from other systems. The waveguides shown in the photograph are part of a system which uses ‘Microwave Reflectometry’ to probe the density of the electrons in the plasma using microwaves at frequencies between 18 and 70 gigahertz. This is designed to provide important measurements of the edge of the plasma, an area called ‘the pedestal’ by fusion physicists. These waveguides have to be removed carefully and later they will be replaced in precisely the same positions. This is to ensure that the signal losses in the waveguide are affected as little as possible.

Work inside the torus has also been progressing. After last week’s in-vessel photographic survey, we have now started to remove some of the carbon tiles from the lower part of the vessel. In particular, all 48 ‘Load Bearing Septum Replacement Plates’ have been removed from the centre of the divertor by remote handling techniques. They were transferred into a container and taken to the ‘Beryllium Handling Facility’ where they will be refurbished.

Work has also continued to remove the duct lining components from the Neutral Beam Injection for upgrading of their cooling systems.