Effective tritium processing using polyimide films

Applying a gas separation membrane module of polyimide hollow fiber films, a new tritium removal system has been studied and designed to develop a more compact and cost-effective system than the conventional type of catalytic reactors and molecular sieves dryers. The recent investigations are focused on the development of a more effective membrane module, specifically, an increase in the processing capacity for a unit module. One idea is to purge the permeated side of the module by using a small part of the bleed flow as a counter-current flow. Another idea is to apply a new polyimide membrane module (Phi 0.1 x 1.8 m) with 5 times larger permeability of N(2) (0.24 std, m(3) h(-1) atm(-1)) than the original one, though the selectivity (permeability ratio of H(2)/N(2): 80) is reduced by about a half. The results show that the purging effect improves the module capacity to be 3 times larger and the new membrane has almost 5 times larger capacity under reasonable operation conditions with the same tritium decontamination ability. The total capacity of a unit module is being improved by more than 10 times. Using the recent results, a case design of the membrane detritiation system is discussed for an application to the ITER scale tritium facility. (C) 1998 Published by Elsevier Science S.A. All rights reserved.