Purity requirements for tokamak fuel

For steady-state operation of a tokamak reactor it is necessary to remove the reaction products from the working chamber and to compensate for burned-out components of the working mixture of tritium and deuterium. For this purpose, a quantity of the gas must be pumped out of the chamber, purified, and reintroduced along with fresh fuel. The consumption of fresh fuel is determined by reactor power and the amount of gas pumped off depends on various factors including reaction product enrichment or depletion of the pump zone and purification conditions. This paper presents simple balance considerations which establish the appropriate estimates and relations for optimizing the fuel purification system