Paper |
Title |
Page |
WPPB07 |
Machine Protection and Advanced Plasma Control in TORE SUPRA Tokamak
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412 |
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- S. P. Bremond, J. Bucalossi, G. Martin, P. H. Moreau, F. Saint-Laurent
EURATOM-CEA, St Paul Lez Durance
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A tokamak is a complex device combining many sub-systems. All of them must have high reliability and robustness to operate together. A sub-system includes its own safety protections and a more integrated level of protection to ensure the safety of the full device. Moreover, plasma operation with several megawatts of additional injected power requires a highly reliable and performing control because uncontrolled plasma displacements and off-normal events could seriously damage the in-vessel components. Such an integrated control system is installed on Tore Supra. It can develop an alternative plasma operation strategy when margins to technological sub-system limits become too small. The control switches to more and more degraded modes, from the nominal one to a fast plasma shutdown. When sub-system limits are nearly reached, the system tries to balance the loads over less solicited parts. Then a modification of the plasma parameters is performed to preserve the plasma discharge in a degraded mode. The third step is a soft and controlled plasma shutdown, including a stopping of additional heating systems. When loads are closed to be uncontrolled, a fast plasma shutdown is initiated.
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