JET's 2007 Shutdown is about to enter "In-Vessel Phase 1"

During the present JET Shutdown a number of new systems that will significantly improve JET's capabilities will be installed. These include a new "ITER-like" Ion Cyclotron Resonant Heating (ICRH) antenna. The installation follows a variety of tests carried out using the test bed. The antenna features a new design aimed at optimising the power coupled to the plasma in a variety of conditions, thus minimising the power reflected and therefore making the heating more efficient. The experiments to be carried out with the "ITER-like" ICRH antenna constitute an important validation of its design and it will provide valuable input into the use of similar heating techniques in ITER. Another JET enhancement is the installation of a high frequency pellet injection system which will be capable of shooting small cubes of deuterium ice into the plasma. The motivation for doing this is to have a direct fuelling method for the plasma core and to mitigate instabilities located in the plasma edge (Edge Localised Modes).

The Shutdown has now proceeded far enough to allow in-vessel work to commence soon. All in-vessel work will be carried out by remote handling, which means that a highly specialised tool on a boom will enter the vessel, controlled from the remote handling control room.

To prepare for this highly specialised activity a large number of tasks had to be executed in order to build up the infrastructure needed to operate the boom. After the removal of diagnostic equipment on two opposite sides of the torus a number of specialised containers including ventilation systems have been mounted (see photo below). One of those contains the boom, its engines and all the tools needed during the shutdown. The other one is a facility for the isolated storage and transport of parts removed from the inside of the vessel.

Phase 1 of the in-vessel activities will be dedicated to different objectives. Many items from in-side the vessel will be removed partly for reasons of accessibility in view of succeeding tasks and partly to refurbish these parts. An intensive photographic survey will give the opportunity to assess the state of sub systems.

30th May, 2007