Plutonium trifluoride

The reaction is exothermic (AH298 = -320.91 kj). Hydrogen is present as a contaminant in hydrogen fluoride, and this results in the formation of plutonium trifluoride (PuF3). Oxygen is added to avoid this. Fluorination is carried out in Hastealloy-C boats lined with platinum. 

Plutonium (III) fluoride Pu + 3F —> PuFj- Also called plutonium trifluoride. 

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). 

Both plutonium trifluoride and tetrafluoride can be prepared by hydro-fluorination of plutonium dioxide. The oxidation-reduction relations of plutonium (III) and (IV) are such that it is readily possible to specify which of the fluorides shall be the product. If the reaction is carried out under reducing conditions, then the product is PuF3, and under oxidizing conditions, PuF4 ... 

PbTi03 LEAD TITANIUM TRIOXIDE 1303 PuF3 PLUTONIUM TRIFLUORIDE 1346... 

Table 5.2 Molar compositions, melting temperatures (°C) [23] and solubility of plutonium trifluoride (mol%) at 600°C in different molten fluoride salts considered as candidates for the fuel and the coolant circuits...

C.J. Barton, Solubility of plutonium trifluoride in fused alkali fluoride-beryllium fluoride mixtures, J. Phys. Chem. 64 (1960) 306—309. 

Its importance depends on the nuclear property of being readily fissionable with neutrons and its availability in quantity. The world s nuclear-power reactors are now producing about 20,000 kg of plutonium/yr. By 1982 it was estimated that about 300,000 kg had accumulated. The various nuclear applications of plutonium are well known. 238Pu has been used in the Apollo lunar missions to power seismic and other equipment on the lunar surface. As with neptunium and uranium, plutonium metal can be prepared by reduction of the trifluoride with alkaline-earth metals. 

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. 

All of die halides except tile hexafluoride and the triiodide may be prepared by the hydrohalogenation of rhe dioxide or of the oxalate of plutonium(lll) at a temperature of about 700°C. With hydrogen fluoride the reaction product is PUF4, unless hydrogen is added to the gas stream, in which case the trifluoride is produced. With hydrogen iodide the reaction product is PuOi, and the other oxyhalides may be formed by the addition of appropriate quantities of water vapor to the hydrogen halide gas. Plutonium triiodide is produced by the reaction of the metal with hydrogen iodide at about 400°C. The hexafluoride is produced by direct combination of the... 

With the exception of thorium, the actinides form trihalides. For uranium and neptunium, reduction of the MX4 compounds with hydrogen is necessary, but for the elements from plutonium onwards the action of the carbon tetrahalide or aluminium halide on the dioxide is usually employed. The trifluorides are insoluble but the rest dissolve to give solutions containing ions. 

Derivation Multiple neutron capture in plutonium in nuclear reactors, plutonium isotopes yield241 Am and 243Am on (3 decay. The metal is obtained by reduction of the trifluoride with barium in a vacuum at 1200C. 

PuFs and Pup4 are important intermediates in the production of plutonium metal. The trifluoride is made by reacting PuOi with a mixture of HF and Hj at 600° C ... 

With the availability of anhydrous plutonium tiifluoride, as discussed in the previous section, the equipment problems associated with the direct conversion of PuFa to Pup4 with HF and oxygen can be avoided by roasting the trifluoride in oxygen to form a mixture of Pup4 and PuOj, according to the reaction... 

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