XA0203301 FUSION TECHNOLOGY 101

FT/P1-18 Diagnostic Neutral Beams For Plasma Studies In Magnetic Fusion Devices A. A. Ivanov, Budker Institute of Nuclear Physics, Novosibirsk, Russia Contact: ivanov~inp.nsk.su Abstract: Low-divergent quasi-stationary neutral beams are often applied in modern magnetic fusion devices as a diagnostic tool providing unique information about plasma parameters. One of most important requirements to these beams is sufficiently large current and energy of the particles, so that the beam can penetrate to the plasma core. Also the duration of the beams must e long enough, i.e. close to that of a plasma discharge, amounting to at least a few seconds for large fusion devices. In the Budker Institute, Novosibirsk, a series of diagnostic hydrogen (or helium) beams were developed which is capable of meeting these requirements for fusion devices of different types and scales. The maximum beam energy of the beams is upto 55 keV and an ion current is up to 5 A (for hydrogen). A pulse duration of the beams ranges from 0.1 ms up to 10 s. The low divergent beams (~0.5O'-0.7O) with initial radius of 3-5 cm cn be geometrically focused at desired region within the plasma. The multiple second beam can be additionally modulated with a frequency variable up to 500 Hz. In the paper, the beam parameters obtained for different modifications of the ion source are presented.

FT/P1-19 Reactor Design Developments in Europe XA0203302 R. Andreani, EFDA Close Support Unit, Max-Planck-Institut . Plasmaphysik, Garching, Ger- many Contact: roberto.andreani ~tech. efda. org Abstract: Future fusion reactor configurations are studied in Europe in the Power Plant Conceptual Study. A number of reactor design concepts were defined, in the '90s, to produce the SEIF report (Safety and Environmental Impact of Fusion) with the objective of providing a clear and well founded reference to establish the future impact of a fusion reactor on the environment. The present stage (stage III of reactor studies) represents a review of the entire situation on the basis of:. the consolidation of our physics understanding from the recent experimentation on JET and the other Tokamaks, the advancements in the design of ITER, the results achieved in the R&D conducted in support of the ITER design. The studies have been based on a modellisation program and consider the advice provided by the utilities and by nuclear industry based on the experience in the design and operation of fission reactors. Two sets of reactor concepts have been established. A first generation (DEMO-like) based on a limited extrapolation from ITER; a second more exploiting advanced physics regimes and more imaginative concepts of nuclear reactor components in view of economic competitiveness.

FT/P 1=20 System Assessment of Helical Reactors in Comparison with Tokamaks II111I 11II 11 11 11 I I K. Yamazaki, National Institute for Fusion Science, Toki, Japan XA0203303 Contact: yamazakiinifs. acykp Abstract: Economically acceptable fusion reactors are required with steady-state and good-confinement plasmas. The tokamak is now best with respect to plasma confinement, however, the current-drive (CD) re-circulation power and the plasma disruptions are worried. In contrast, the helical system is expected as a steady-state reactor, but becomes a rather big and expensive system. System assessments have been done for LED (Large Helical Device)-type reactors and quasi-axisymmetric modular reactors in comparisons with ITER-like tokamak designs. High plasma temperature operation is required in tokamaks to increase CD efficiency and to reduce CD power. However, rather low temperature operation is feasible in helical system. The weight and cost of the LED-type fusion island are two times higher than those of reference tokamak design with same beta value and same net electric power. However, no need of CD power and the less-frequent replacement of blanket/heating equipments within the permissible neutron wall load can contribute to the reduction in COE of helical reactors. The unique differences between helical and tokamak reactor assessments are clarified.