Mass measurement uncertainty for plutonium aliquots assayed by controlled-potential coulometry

Abstract

Minimizing plutonium measurement uncertainty is essential to nuclear material control and international safeguards. In 2005, the International Organization for Standardization (ISO) published ISO 12183 ''Controlled-potential coulometric assay of plutonium,'' 2nd edition. ISO 12183:2005 recommends a target of ±0.01% for the mass of original sample in the aliquot because it is a critical assay variable. Mass measurements in radiological containment were evaluated and uncertainties estimated. The uncertainty estimate for the mass measurement also includes uncertainty in correcting for buoyancy effects from air acting as a fluid and from decreased pressure of heated air from the specific heat of the plutonium isotopes.

A mechanistic study on the electrocatalysis of the Pu(iv)/Pu(iii) redox reaction at a platinum electrode modified with single-walled carbon nanotubes (SWCNTs) and polyaniline (PANI)

“…The coulometric technique on the platinum electrode with the reversible Pu(IV)/ Pu(III) couple in mineral acids is most frequently followed for the accurate determination of Pu. [1][2][3][4][5][6][7][8][9][10][11][12] 1-3 M sulphuric acid (H 2 SO 4 ), depending on the amount of Pu, gives satisfactory results by coulometry. However, the fouling of platinum electrodes is encountered very often because of its passivation by an oxide layer or due to the adsorption of some organic molecules present in the analyte solution.…”