Determination of some non-metallic impurities in nuclear grade sodium

Non-metallic impurities - oxygen, chlorine and sulphur -were determined in residues of vacuum distillation of nuclear grade sodium metal. Oxygen was determined by first derivative potentiometry with 0.05 M perchloric acid. Chlorine in form of chloride was determined by potentiometric titration in 80% acetone with 0.01 N AgNO3 (down to 5 μg Cl-) or by polarography (about 3 μg Cl-/ml). Sulphur in form of sulphate was determined by potentiometric titration in 80% acetone with 0.01 M BaCl2 (limit 10 μg S, corresponding to about 1 ppm S); sulphur in form of sulphide was determined in metal sodium photometrically using a ''Diamino'' reagent (1 μg S, 3 ppm S). (author)