Analytical methods for fissionable material determinations in the nuclear fuel cycle. Progress report, October 1, 1976--September 30, 1977

Abstract

Development of dissolution techniques for difficult-to-dissolve nuclear materials, development of methods and automated instruments for Plutonium and uranium determinations, preparation of plutoniumcontaining materials for the Safeguards Analytical Laboratory Evaluation (SALE) program, analysis of SALE uranium materials, preparation of certified reference material plutonium metal, measurement of longer plutonium isotope half-lives, and study of ion exchange behavior of elements in various media continued. Gas-solid reaction of carbonyl chloride with ui mium-bearing materials at elevated temperature is superior to reaction with chlorine for uranium volatilization and separation. Neither reaction with a variety of nonaqueous solvents nor reaction with molten selenium oxide provides practical dissolution of refractory materials characteristic of nuclear fuel cycle materials. The LASL automated spectrophotometer has been used to determine 0.1-mg amounts without instrumental or procedural changes. A microgram-sensitive spectrophotometric method for uranium has been developed, and the automated spectrophotometer is being modified to its use. A controlled-potential coulometric method has been developed for selective determination of plutonium. An automated analyzer to use this method is being built. Uranium-plutonium mixed oxide powder, for SALE samples, has not remained stable during storage, but high-density pellets have. In a DOE interlaboratory program, the half-life of M *Pu has been measured, experiments on M1Pu half-life measurement are in progress, and M°P u half-life measurement is planned. Ion exchange distributions for over SO elements have been measured to determine cation exchange in nitric acid and anion exchange in both hydrobromic and hydriodic acids.

Automated controlled-potential coulometer for plutonium determination

“…The first instrument was an automated spectrophotometer for the highly selective determination of low milligram amounts of uranium and plutonium with precisions of about 1% relative standard deviat'on (RSH).' This instrument was later modified 2 to use an additional spectrophotometric method 3 to selectively determine microgram amounts of uranium. The automated controlled-potential analyzer described here determines low milligram amounts of plutonium with high selectivity and a 0.1% RSD.…”