AN ANION-EXCHANGE TECHNIQUE FOR SEPARATION OF NA AND K FOR NEUTRON-ACTIVATION ANALYSIS OF W-TI ALLOY

A radiochemical neutron activation analysis procedure has been develop ed for:he determination of sodium and potassium at parts per billion l evels in high purity tungsten/titanium alloy material. The procedure i nvolves the use of an anion exchange separation for purifying sodium a nd potassium activities from the alloy's matrix activities, Sc-46 and W-187. In addition, the use of two sequential sample loadings on the r esin column prior to elution of the matrix activities has been investi gated. Irradiation of 200 mg of the alloy results in a sample of nearl y 1 Ci which must be handled in a remote manipulation cell. After acid dissolution of the sample, the sample solution in 1 M HF was loaded o nto the column. Elution of the sodium and potassium was accomplished u sing 40 mi of 1M HF. Similar loading and elution of the second sample was followed by the elution of matrix activities with a solution of 1M HF + 6M HCl. Extensive tracer experimentation was employed to establi sh the possibility of retaining the matrix activities on the column wh ile a second sample solution was processed, thus greatly increasing th e throughput in terms of the number of samples analyzed per day. The d etection limits of Na and K using the method developed are 4.0 ppb and 200 ppb, respectively.