Current engineering issues and further upgrading of the JET tokamak
The design of the Joint European Torus (JET) was conceived with inherent flexibility to accommodate modifications and upgradings, while preserving basic machine structure. The first major upgrading was to increase the plasma current capability from 4.8 MA to 7 MA in limiter configuration and from 3.0 MA to 5 MA in X-point configuration. The second change was the progressive covering of the vessel walls with low Z-materials such as graphite and beryllium. The most recent major modification was to make JET into a pumped divertor machine. Three divertors are being tested in sequence (Mark I, II, IIGB), in support of the international thermonuclear experimental reactor (ITER) design. JET is operating at present with Mark II both in deuterium-deuterium (D-D) and in deuterium-tritium (D-T). Thus, the installation of Mark IIGB will be performed using only remote handling techniques. Divertor plasmas are more vertically unstable, and so a new plasma control system had to be designed and implemented. The engineering instrumentation of the machine has been upgraded, for machine protection and to monitor and study new phenomena such as sideways vessel displacements, caused by plasma disruptions. An in depth reassessment of the toroidal coils, of the mechanical structure and of the vessel is in progress.
Bibliographic Reference: Report: JET-P(97)49 EN (1997) 12pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (GB)
Record Number: 199810253 / Last updated on: 1998-03-09
Original language: en
Available languages: en