Plutonium Sulfate Tetrahydrate, a Proposed Primary Analytical Standard for Plutonium.

Abstract

Extraction, % 15 30 60 120 240 89.2 99.4 99.9 99.7 99.5 a Under conditions ae outlined in Procedure.The divalent CrO,-2 ion does not form an ion-association complex with the quaternary ammonium ion. Thus contact with caustic completely strips the chromium from the organic phase. Chromium could not be completely removed from methyl isobutyl ketone with the strip solution in the absence of the quaternary ammonium ion. This may be due to some type of solvation mechanism.Scavenging the strip phase with ferric hydroxide separates hydrolyzable ions that are coextracted with the chromium.Oxidization of the Cr(II1) in basic Plutonium Analytical solution appeared worthwhile and was investigated. A sample of aged fission products was treated according t o the first steps in the recommended procedure, followed by dissolution of the Cr(OH)a Mith 1 5 M NaOH. Sodium hypochlorite was added and after the oxidation was completed, an iron scavenging was performed. After filtering and acidifying, the Cr(Y1) n a s extracted according to the procedure. A ?-ray spectrum of the strip phase showed copious quantities of rutheniuni activity as well as some zirconiuniniobium activity in the final product. Apparently much of the ruthenium x i s in an extractable form and follon ed t!ie chrorniurn. Hence, in the recommended procedure, ruthenium is removed in the perchloric acid oxidation step. The yield is conveniently determined on a n aliquot of the strip phase by a spectrophotometric determination of chromate a t 370 mp.Decontamination by this procedure from 3-day and 3-month cooled fission product mixtures is shown in Figures 3 and 4, respectively. With irradiated stainless steel 300-type alloys, no foreign activity was found in the final chromium fraction.Six aliquots of chromium-51 activity were carried through the recommended procedure and the area under the 320k.e.17. photopeak m-as measured. The relative standard deviation was less than 1%. The average yield is 85% and the time of analysis is approvimately 1 hour. llTERATURE CITED(1) Dean, J. A., Beverlj-, lf. L., Ax41,.

Dicesium Plutonium Hexachloride, a Proposed Primary Standard for Plutonium.

“…Cs2PuCl6 can be obtained in a pure state by a single precipitation, whereas pure metallic plutonium is difficult to obtain. Other difficulties inherent in the storage and use of the metal (16) are not shared by Cs2PuCl6.…”

“…In solvents such as acetone, acetonitrile, and pyridine, the titration curves have a steep slope in the buffered region, owing to the intermolecular association of the acid anion with the free acid (4,10,16,17). Evidently, this association is not appreciable in tertiary butyl alcohol.…”

“…The problem of obtaining metal of known purity has been overcome recently by a pluto-nium metal standard, available in limited quantities from the National Bureau of Standards, which is 99.97% pure. Other difficulties associated with the use of the metal as a standard have been discussed (16).…”

“…Recent work has indicated that it can be prepared, under special conditions, in a form that is not so hygroscopic (17,19). Plutonium sulfate tetrahydrate has been evaluated and is proposed as a primary analytical standard for plutonium (16).…”

Synthesis and trace metal characterization of potassium plutonium sulphate: working reference material for plutonium

“…Several attempts were observed in the literature for the evaluation of different physicochemical properties of plutonium working standard [31,32]. Rogers and Brown [33] prepared a radiometric and calorimetric primary standard for 238 Pu.…”