Systems for the safe operation of the JET tokamak with tritium

In 1997, the JET device was operated for an extensive campaign with deuteri um-tritium (D-T) plasmas (the DTE1 campaign). A comprehensive network of ma chine protection systems was necessary so that this experimental campaign c ould be executed safely without damage to the machine or release of activat ed material. This network had been developed over many years of JET deuteri um plasma operation and therefore the modifications for D-T operation was n ot a significant problem. The DTE1 campaign was executed successfully and s afely and the machine protection systems proved reliable and robust and, in the limited cases where they were required to act, functioned correctly. T he machine protection systems at JET are described and their categorisation and development over time are summarised. The management, commissioning an d operational experience during DTE1 are discussed and some examples of fau lt scenarios are described. The experience with protection systems at JET h ighlights the importance of correct design and philosophy decisions being t aken at an early stage. It is shown that this experience will be invaluable data input to the safe operation of future large fusion machines. (C) 1999 JET Joint Undertaking. Published by Elsevier Science S.A. All rights reser ved.