Effect of beryllium on plasma performance in JET
- 1 November 1990
- journal article
- Published by IOP Publishing in Plasma Physics and Controlled Fusion
- Vol. 32 (11), 837-852
- https://doi.org/10.1088/0741-3335/32/11/002
Abstract
JET is investigating beryllium as material for walls and limiters. Studies were carried out with initially a thin layer of beryllium evaporated onto the walls of the machine, later in addition the graphite material of the belt limiter was exchanged against beryllium. The use of this material was generally beneficial for the plasma behaviour. Combined with a reduction in the oxygen content, strong pumping of hydrogen isotopes was found which allowed JET to widen considerably the operational space with respect to ion temperatures, densities and plasma purity. In this paper a comparison of the plasma performance with graphite and beryllium will be presented. The author discusses especially the impurity behaviour with respect to fluxes, concentrations, effective charge and dilution, and reports on density limits, disruption behaviour, wall pumping, hydrogen isotope retention, and the power handling capability of the beryllium limiter in the present design. Examples of improved plasma performance are given.Keywords
This publication has 8 references indexed in Scilit:
- Hydrogen and helium recycling in tokamaks with carbon wallsJournal of Nuclear Materials, 1989
- Experimental and numerical investigations of the beryllium concentrations in the tokamak unitorJournal of Nuclear Materials, 1989
- Disruptions in JETNuclear Fusion, 1989
- The beryllium limiter experiment in ISX-BNuclear Fusion, 1986
- The interpretation of plasma edge conditions in tokamaksPlasma Physics and Controlled Fusion, 1985
- A model for atomic hydrogen-metal interactions — application to recycling, recombination and permeationJournal of Nuclear Materials, 1985
- Experimental study of the compatibility of beryllium limiters with a tokamak plasmaNuclear Fusion, 1984
- Hydrogen solubilisation into and permeation through wall materialsJournal of Nuclear Materials, 1979