SUPERPERMEABILITY - CRITICAL-POINTS FOR APPLICATIONS IN FUSION

One of key points for the applications of superpermeable membranes in fusion is the question of the upper limit of the permeation flux densi ty. Theoretical estimates give the maximum fluxes of similar to 10(19) cm(-2) s(-1) for V group metal membranes. The permeation fluxes of up to 3 X 10(16) and 4 X 10(17) cm(-2) s(-1) were achieved using Nb and thermal atomic hydrogen in the direct membrane experiments and in simu lation absorption experiments respectively. Achievement of higher flux es has been limited by the experimental equipment opportunities. Anoth er important point is the reliability of membrane operation in the pre sence of chemically active gases. No negative effects of CH4, CO and O -2 specially introduced on a superpermeable Nb membrane were detected during 3000 h of operation. Such membranes coupled with special hydrog en atomizers can be easily incorporated into the up-to-date ITER desig n concept. The membranes installed in every of the 24 ducts might isol ate >90% of D/T with the flux densities already reached.