The redox chemistry of neptunium in γ-irradiated aqueous nitric acid
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Bruce J. Mincher
Abstract
The redox chemistry of neptunium in irradiated 4 M nitric acid was investigated using γ-ray irradiation and UV/Vis spectroscopic measurements. Irradiation caused changes in the abundances of Np(V) and Np(VI) regardless of the initial fractional components of these oxidation states. At low absorbed doses Np(V) was oxidized to Np(VI) in irradiated solution, due to its reaction with oxidizing, radiolytically-produced, free radicals. However, when sufficient radiolytically-produced nitrous acid accumulated, the reduction of Np(VI) to Np(V) occurred, even at this high nitric acid concentration. Neptunium(IV) was not produced. A kinetic model which incorporates the standard water radiolysis reactions, estimated radical yields for 4 M HNO3, and rate constants for neptunium reactions available from the literature was used to successfully reproduce the experimental results.
© by Oldenbourg Wissenschaftsverlag, München, Germany
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Articles in the same Issue
- Cross section measurements of a few threshold reactions induced by fast neutrons from an Am/Be source: integral tests of differential neutron reaction cross section data
- Prediction of the thermal release of transactinide elements (112 ≤ Z ≤ 116) from metals
- Complexation thermodynamics and structural studies of trivalent actinide and lanthanide complexes with DTPA, MS-325 and HMDTPA
- Synthesis and characterization of thorium, uranium and cerium oxide nanoparticles
- Improved radioanalytical method for the simultaneous determination of Th, U, Np, Pu and Am(Cm) on a single TRU column by alpha spectrometry and ICP-MS
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- The incorporation of europium into apatite: anew explanation
- Instrumental neutron activation analysis for the study of size-fractionated airborne particulate matter samples
