Scientific preparation for future D-T campaigns at JET in support of ITER

JET is preparing for deuterium-tritium operation in 2015 with the newly installed ITER-like Wall, neutral beam enhancements (35MW, 20s) and diagnostics upgrades, as part of a phased approach to the full exploitation of JET. Performance projections for stationary ITER scenarios predict Q~0.160.20 for ELMy H-mode plasmas at 4.5MA/3.6T, Q~0.3-0.5 for hybrid plasmas at 3.5MA/3.45T to 4.1MA/4.0T and Q~0.1-0.4 for advanced scenario plasmas at 1.8MA/2.7T to 2.3MA/3.45T. Key physics studies would concentrate on isotope mass dependence of the edge pedestal, ELM size and ELM mitigation as well as the access to H-mode. ICRH schemes for ITER could be tested, while sufficient alpha particles would be available for heating and instability studies. The tritium retention (using the Active Gas Handling Systems at JET) and cleaning methods for tritium removal could be assessed in addition to testing D-T diagnostics and 14 MeV neutron calibration techniques. Introduction JET has unique capabilities such as operation with tritium, confining alpha particles produced in D-T fusion reactions, use of beryllium as a first wall material, and remote handling systems for maintenance and refurbishments of the interior of the device. Previous D-T campaigns at JET in 1997 (DTE1, [1]) produced up to 16.1MW of fusion power transiently, in an ELM free H-mode at Q~0.6, and 4MW in stationary ELMy H-mode conditions at Q=0.18, producing 22 MJ of fusion energy in a single pulse ([1] and Figure 1). These experiments also showed that the fuel mixture impacts strongly on performance. During 2003, a third period of JET D-T operation was carried out in which trace levels of tritium (~1-3%) in deuterium plasmas were used to study the fundamental processes for plasma transport and test specialised diagnostics at low fusion power. JET has maintained its D-T capability and after more than 15 years of development of ITER regimes of operation, the impact of using a D-T fuel mix will need to be assessed on JET in advance of ITER operations. * See the Appendix of F. Romanelli et al., Proceedings of the 23rd IAEA FEC 2010, Daejeon, Korea F u s io n P o w e r (M W ) Time (s) 0 1 2 3 4 5 6 5 10 15 TFTR (1994) JET (1997)