Description: Sputtering erosion of the proposed ITER divertor has been analyzed using the REDEP computer code. A carbon coated plate at medium and low plasma edge temperatures, as well as beryllium and tungsten plates, have been examined. Peak net erosion rates for C and Be are very high (/approximately/20--80 cm/burn/center dot/yr) though an order of magnitude less than the gross rates. Tritium buildup rates in codeposited carbon surface layers may also be high (/approximately/50--250 kg/burn/center dot/yr). Plasma contamination, however, from divertor sputtering is low (/approx lt/.5%). Operation with low Z divertor plates, at high duty factors, therefore appears unacceptable due to erosion, but may work for low duty factor (/approximately/2%) ''physics phase'' operation. Sweeping of the poloidal field lines at the divertor can reduce erosion, by typical factors of /approximately/2--8. A tungsten coated plate works well, from the erosion standpoint, for plasma plate temperatures of /approximately/40 eV or less. 18 refs., 11 figs., 3 tabs.
Date: July 1, 1989
Creator: Brooks, J.N.
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