Plutonium oxides direct oxide reduction

Electrorefining. Impure plutonium metal from MSE and Direct Oxide Reduction (DOR) is sent to an electrorefining operation (J3). In plutonium electrorefining, impure plutonium... 

Direct Oxide Reduction. Implementation of the DOR process into production Ts currently underway. Plutonium oxide from foundry operations, hydriding, and other sources is calcined in... 

The use of this direct oxide reduction process is replacing fluoride reduction as it eliminates neutron exposure to operating personnel (alpha particles from plutonium decay have sufficient energy to eject neutrons from fluorine by the a,n reaction) and eliminates reduction residues which require subsequent recovery. 

A. Process Schematic. A schematic of the main process sequence for the conversion of plutonia scrap to high-purity metal is shown in Figure 2. Plutonia scrap is fed to both the direct oxide reduction (DOR) process and the plutonium tetrafluoride production/ reduction process. 

Direct Oxide Reduction. In DOR, plutonia is reduced with calcium metal to form plutonium metal and calcium oxide.2 3 The reaction takes place in a CaCl2 solvent which dissolves the calcium oxide and allows the plutonium metal to coalesce in the bottom of the crucible. 

The skull metal and oxide are first completely burned to oxide by heating in air to 400-500°C. The plutonium metal spontaneously burns and is collected as a green Pu03 powder. This oxide is recycled back as feed for Direct Oxide Reduction. This process is normally 100% efficient with only a small plutonium residue showing up in items such as clean-up rags. 

Calcinm glectrowinning in piutniiium production. A potential application of inorganic membranes in radioactive waste treatment is in the industrially practiced direct oxide reduction process. In this process plutonium oxide is calciothermit y reduced to plutonium in the presence of calcium chloride according to the following reaction ... 

Plutonium metal is prepared by two methods--direct reduction of the oxide by calcium (DOR)U,2J, and reduction of PuF by calcium in our metal preparation line (MPL)(3) (see Figure 1). In the DOR process, the plutonium contenF of the reduction slag is so low that the slag can be sent to retrievable storage without further processing. Metal buttons that are produced are no purer than the oxide feed and/or the calcium chloride salt. Los Alamos purifies the buttons by electrorefin-ing(4i,5 ), yielding metal rings that are > 99.96 percent plutonium. 

The following pages will describe several examples of pyrochemical processing as applied to the recycle of plutonium, and will briefly review the fundamental chemistry of these processes. We shall review the conversion of plutonium oxide to plutonium metal by the direct oxide reduction process (DOR),the removal of americium from metallic plutonium by molten salt extraction (MSE), and the purification of metallic... 

Plutonium trifluoride. Plutonium trifluoride can be converted directly to plutonium metal, or it is an intermediate in the formation of PUF4 or PUF4 -PUO2 mixtures for thermochemical reduction, as described in Sec. 4.8. The stabilized Pu(III) solution, produced by cation exchange in one of the Purex process options for fuel reprocessing, is a natural feed for the formation of plutonium trifluoride, as is shown in the flow sheet of Fig. 9.9 [03]. A typical eluent solution from cation exchange consists of 30 to 70 g plutonium/liter, 4 to 5 Af nitric acid, 0.2 Af sulfamic acid, and 03 Af hydroxylamine nitrate. The sulfamic acid reacts rapidly with nitrous acid to reduce the rate of oxidation of Pu(III) to about 4 to 6 percent per day. Addition of ascorbic acid to the plutonium solution just before fluoride precipitation reduces Pu(IV) rapidly and completely to Pu(III). 

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