Neptunium separation

Zhu, Z., He, J., Zhang, Z. et al. 2004. Uranium/plutonium and uranium/neptunium separation by the Purex process using hydroxyurea. J. Radioanal. Nucl. Chem. 262 (3) 707-711. 

Nagasaki, S., Wisnubroto, D.S., Enokida, Y., Suzuki, A. 1994. Neptunium separation from nitric acid solutions with CMPO. 4th Int. Conf. Nuclear Fuel Reprocessing and Waste Management, RECOD 94 Proceedings Vol. 3, London, UK, April 24-28. 

The procedure involves the coprecipitation of the transuranic nuclides on calcium fluoride from acid solution after reduction of the plutonium and neptunium with bisulfite. The calcium fluoride precipitate is dissolved in aluminum nitrate-nitric acid solution and the plutonium and neptunium separated on an ion-exchange resin column. The column... 

Initially, the only means of obtaining elements higher than uranium was by a-particle bombardment of uranium in the cyclotron, and it was by this means that the first, exceedingly minute amounts of neptunium and plutonium were obtained. The separation of these elements from other products and from uranium was difficult methods were devised involving co-precipitation of the minute amounts of their salts on a larger amount of a precipitate with a similar crystal structure (the carrier ). The properties were studied, using quantities of the order of 10 g in volumes of... 

The wastes from uranium and plutonium processing of the reactor fuel usually contain the neptunium. Precipitation, solvent extraction, ion exchange, and volatihty procedures (see Diffusion separation methods) can be used to isolate and purify the neptunium. 

Uranium-239 [13982-01 -9] has a half-life of 23.5 min neptunium-239 [13968-59-7] has a half-life of 2.355 d. Recycling or reprocessing of spent fuel involves separation of plutonium from uranium and from bulk fission product isotopes (see Nuclearreactors, chemical reprocessing). 

Burney, G. A. Separation of Neptunium and Plutonium by Anion Exchange. U.S. AEC Report DP-689, E. I. duPont de Nemours Co., Savannah River Laboratory, Aiken, SC, 1962. 

Neptunium is similar to uranium in that the potentials of the four oxidation states are widely separated. There have been only a few studies on the hydrolytic reactions of neptunium. Np02 unlike U02 is comparatively stable and represents a transition... 

Subsequently, solvent extraction was applied to recover the fission product technetium from the residue remaining after the fluorination of irradiated uranium fuel elements . The residue was leached with concentrated aluminum nitrate solution, which was extracted by 0.3 M trilaurylamine in a hydrocarbon diluent. After separation of uranium, neptunium, and aluminum nitrate, technetium was back extracted into a 4 N sodium hydroxide solution. 

Allow most of the neptunium to coextract with U(VI) as Np(IV) or Np(VI) and separate it in downstream uranium purification cycles... 

Fluorine is used in the separation of uranium, neptunium and plutonium isotopes by converting them into hexafluorides followed by gaseous diffusion then recovering these elements from nuclear reactors. It is used also as an oxidizer in rocket-fuel mixtures. Other applications are production of many fluo-ro compounds of commercial importance, such as sulfur hexafluoride, chlorine trifluoride and various fluorocarbons. 

McMillan had been sure that another element was present in his neptunium fractions. In December, 1940, Seaborg, A. C. Wahl, and J. W. Kennedy separated from neptunium a fraction which had alpha activity and which showed at least two oxidation states. It required stronger oxidizing agents to oxidize this substance than were needed for neptunium. The new element was identified as 94. The notes reporting this discovery were submitted to the journals early in 1941, but were not published until 1946 (67, 68). 

All the early work on plutonium was done with unweighable amounts on a tracer scale. When it became apparent that large amounts would be needed for the atomic bomb, it was necessary to have a more detailed knowledge of the chemical properties of this element. Intensive bombardment of hundreds of pounds of uranium was therefore begun in the cyclotrons at Berkeley and at Washington University in St. Louis. Sepa-ration of plutonium from neptunium was based on the fact that neptunium is oxidized by bromate while plutonium is not, and that reduced fluorides of the two metals are carried down by precipitation of rare earth fluorides, while the fluorides of the oxidized states of the two elements are not. Therefore a separation results by repeated bromate oxidations and precipitations with rare earth fluorides. 

Albright, D. Barbour, L. 1999. Separated neptunium and americium. In Albright, D. O Neil K. (eds) The Challenges of Fissile Material Control. ISIS, Washington, DC, 85-96. 

Uranium. Perricos and Belkas (25) have determined uranium in six coals by neutron activation followed by separation of the uranium daughter neptunium-239 by carrier-free extraction chromatography. The coals, from mines in northern Greece, had very high uranium concentrations (0.012-0.037%). However, uranium at the few parts per million level found in most coals could no doubt be determined by a modification of this method. 

Uchiyama, G., Asakura, T., Hotoku, S., Fujine, S. 1998. The separation of neptunium and technetium in an advanced PUREX process. Solvent Extr. Ion Exch, 16 (5) 1191-1213. 

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