GB1247590A - Method and apparatus for the purification of heavy water - Google Patents

Abstract

1,247,590. Purification of heavy water. COMMISSARIAT A L'ENERGIE ATOMIQUE. 11 June, 1969 [21 June, 1968], No. 29547/69. Heading C1A. [Also in Divisions B1 and G6] The hydrogen and tritium content of heavy water is reduced by diverting a continuous flow of heavy water from a reactor to an isotopic exchange reaction with deuterium, passing the contaminated deuterium to a chromatographic fractionation whereby hydrogen and tritium are separated leaving pure deuterium which is recycled to the isotopic exchange reaction. Solid catalysts such as Pt or Pd on inert supports, iron oxide or Ni deposited on chromium oxide can be used to initiate the exchange reaction or alternatively thermal activation may be used, the exchange temperature being preferably 80-400‹ C. in the former case and 800-1200‹ C. in the latter. The fractionation may be performed in a moving solid or static solid column. In the former embodiment the impure D 2 enters the column at an intermediate point tritium rich D 2 leaving the top of the column and hydrogen rich D 2 leaving the bottom of the column. The solid absorbent is heated as it leaves the bottom of the column, freeing the absorbed gases which then pass up the column, the solid being recycled to the top of the column. Alternatively (see Fig. 3) the impure D 2 enters column 17 at 23. Tritium rich D 2 leaves via 24. The hydrogen rich D 2 passes via 25 to a second column 18 from which pure D 2 leaves via 27, hydrogen rich D 2 being removed at 26. This arrangement may be reversed, i.e. hydrogen rich D 2 may be separated in a first stage. The separating solid is preferably palladium based. The hydrogen rich D 2 may, by methods known per se, be subjected to isotopic enrichment to recover part of the heavy water. The tritium rich D 2 may similarly be treated to recover the tritium.