Plutonium dioxide is ainorganic compound, molecular weight 274.00.It is the most stable oxide of plutonium.Greenish brown to yellowish brown powder.It is highly toxic and radioactive.Specific gravity 11.46.Melting point 2400 ℃.Insoluble in water, soluble in hot concentrated sulfuric acid.Its particles are fine and easy to float in the air. All operations must be closedGlove boxIn.Plutonizableperoxide, oxalatehydroxideAnd nitrate are heated to 800~1000 ℃ in oxygen.For breeder and power reactorsnuclear fuel。[1]
Plutonium dioxide is a green brown to yellow brown solidheliumThe melting point is 2280 ± 30 ℃, and the vapor pressure is very low;UsuallyPlutonium oxalateandPlutonium nitrateIt is obtained by burning.The density of plutonium dioxide by high-temperature burning method is 11.46g/cmthree, genusFluorite structure。It is usually green and related to particle size.Plutonium dioxide, especially after sintering at high temperature, is very difficult to dissolve. It is very slowly and incompletely dissolved in hydrochloric acid and nitric acidHydrobromic acidThe medium dissolves quickly withSodium bisulfateSuch fluxes can dissolve plutonium dioxide under melting conditions.Plutonium dioxide has the advantages of high melting point, high irradiation stability, compatibility with metals and reactor coolant, and easy manufacture.be used asPower reactorNuclear fuel is also often associated withUranium dioxideMixedMixed oxide fuel。
Preparation method
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Burning plutonium or its compounds in air（phosphateExcept), and the formation of plutonium dioxide when heated to 1000 ℃ containing oxides in vacuum or inert atmosphere.Holley et al. used burnt Pu or Pu oxalate, or PuperoxideThe carbon dioxide was prepared.It is important to precipitate the initial compounds in the form of crystals, because colloidal precipitates are easy to generate black and impure oxides when burning.
Heating Pu or Pu in airoxalateAt 1000 ℃, very pure and crystalline dioxide can be produced.To avoid rapid decomposition, the heating speed must be very slow before about 700 ℃, and then the temperature can quickly rise to 1000 ℃ to remove the last trace of carbon.Peroxide can be burned in a similar way, but it must be slowly heated to about 200 ℃ to avoid splashing caused by rapid decomposition.When heated to 700 ℃, sulfate can be removed.To ensure high purity products, heat to 1000 ℃.[2]
application area
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Due to its high melting point, radiation stability, mutual compatibility with metals and easy preparation, plutonium dioxide is a suitable form of nuclear fuel.Plutonium dioxide can react with hydrogen fluoride at high temperature to formPlutonium trifluoride, generated in the presence of oxygenplutonium tetrafluoride ；Generated by interaction with fluorine at high temperatureplutonium hexafluorideAnd reacted with zinc magnesium alloy to produce plutonium.
The melting point of β - plutonium trioxide is 2085 ± 25 ℃;It can be made by heating plutonium dioxide and carbon in helium to 1625 ℃.α - plutonium trioxide can be prepared by heating plutonium dioxide in vacuum to 1650~1800 ℃.α - Plutonium trioxide is produced by the loss of oxygen when plutonium dioxide melts, and its melting point is 2360 ± 20 ℃.
