Method of separation of yttrium-90 from strontium-90

A method is described for purifying Y-90 from a Sr-90/Y-90 ''cow'' wherein raw Sr-90/Y-90 source containing impurities is obtained from nuclear material reprocessing. Raw Sr-90/Y-90 source is purified to a fresh Sr-90/Y-90 source ''cow'' by removing impurities by addition of sodium hydroxide and by removing Cs-137 by further addition of sodium carbonate. The ''cow'' is set aside to allow ingrowth. An HDEHP organic extractant is obtained from a commercial supplier and further purified by saturation with Cu(II), precipitation with acetone, and washing with nitric acid. The ''cow'' is then dissolved in nitric acid and the purified HDEHP is washed with nitric acid and scrubbed with either nitric or hydrochloric acid. The dissolved ''cow'' and scrubbed HDEHP are combined in an organic extraction, separating Y-90 from Sr-90, resulting in a Sr-90/Y-90 concentration ratio of not more than 10(E-7), and a metal impurity concentration of not more than 10 ppm per curie of Y-90. The separated Y-90 may then be prepared for delivery. 1 fig