Metal foil pump

[mkovari]

PROCESS should really include a consistent particle balance model as well an the energy balance, including the exhaust pumping. The primary exhaust pump proposed for EU-DEMO is the metal foil pump.

While I am still sceptical of this concept, there is a new paper showing results that might form the basis of a model.

Direct internal recycling fractions approaching unity by Chao Li, Colin A. Wolden et al

The metal foil pump removes pure H₂ (i.e. D and T) from the exhaust, leaving behind He and other impurities, together with some fraction of the H₂ that doesn't pass through the pump, which are pumped away using some other technology. In this paper, the fraction of H2 that gets through the foil is called the Direct Internal Recycling (DIR) fraction, since this gas can go straight back to the fuelling system without requiring further purification or isotope separation.

The authors' conclusion is that ∼20 m² metal foil pump area would suffice to process the exhaust with 90 % DIR fraction at a flowrate of 100 Pa·m³·s^-1 using continuous pumping.

Any comments @jmorris-uk @ajpearcey ?