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A model for diffusion in the tokamak edge and application to the modular pump limiters on Tore Supra

Technical Report ·
OSTI ID:6985817

The relative positioning of the limiter modules on Tore Supra is investigated with the objective of optimizing the overall performance of the system and the operational flexibility of the experiment. Working within the constraints imposed by the availability of ports on Tore Supra, the best limiter configuration for a system of seven modular limiters is identified. The performance to be expected for this optimized configuration for various modes of Tore Supra operation is reported. We find that very long flux tubes must be avoided if the limiter system is to operate near its full design capacity of 8.0 MW. For the assumed edge conditions, as discussed in the text, Bohm diffusion with a plasma temperature of 150 eV at the last closed flux surface, the configuration identified can exhaust between 17--21 torr/minus/1/s while removing 5--8 MW of power incident on the limiter surfaces. Operational modes that pump as much as 26 torr/minus/1/s are also possible if incident power levels are reduced to 4.0 MW. Operation with large amounts of auxiliary heating, in excess of 15 MW, is also possible by power sharing with the actively cooled inner bumper limiter. In this situation particle pumping rates may be as low as 9 torr/minus/1/s. 19 refs., 11 figs., 1 tab.

Research Organization:
Sandia National Labs., Albuquerque, NM (USA)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
6985817
Report Number(s):
SAND-87-2716; ON: DE88010154
Country of Publication:
United States
Language:
English