Plutonium hydrides

The very chemically reactive plutonium hydride is usually decomposed in a vacuum-tight furnace capable of attaining a temperature of 700°C. Plutonium hydride that is decomposed under vacuum at temperatures below 400°C forms a very fine (<20y) metallic powder above 500°C the powder begins to sinter into a porous frit which melts at 640°C to form a consolidated metal ingot. This metal typically contains significant oxide slag but is suitable for feed to either molten salt extraction or electrorefining. 

Plutonium components, normally kept under argon, were accidentally exposed to air and moisture, probably forming plutonium hydride and hydrated oxides. When the plastics containing bag was disturbed, ignition occurred, causing widespread radiation contamination. 

Plutonium compounds, 19 687-691 protection against, 19 702 Plutonium dioxide, 19 688—689 Plutonium fuel fabrication facilities, 17 547 Plutonium-gallium alloys, 19 683-684 Plutonium halides, 19 689-690 Plutonium hexafluoride, 19 689 Plutonium hydrides, 19 690 Plutonium ions... 

Compact (bulk) plutonium hydride (Puj s to PuH2,65) has been obtained by hydriding under pressure a-Pu in the plastic range (350-400 °C). Protactinium trihydride is less stable than uranium trihydride ... 

Plutonium nitride. Unlike the corresponding uranium-nitrogen system, only the one plutonium nitride PuN exists. It is prepared by heating plutonium hydride in nitrogen at 250 to 400 C, by reacting plutonium metal with a hydrogen-ammonia mixture at 600°C, or by direction reaction of molten plutonium with nitrogen at 1000 C. Plutonium nitride forms solid solutions with UN. However, because of the appreciable volatility and dissociation of PuN at temperatures at about 1600 C and above, the ternary (U, Pu)N is less attractive as a nuclear fuel than pure UN [K2, S4]. 

Plutonium hydrides. Plutonium hydrides are made by reacting plutonium metal with hydrogen at atmospheric pressure and at temperatures between 50 and 300 C, forming a series of hydrides up to PuHa. Plutonium hydride is a useful intermediary in the formation of other plutonium compounds. 

Enthalpies and entropies of formation for cubic plutonium hydrides at a median T = 550 K. 

Fig. 20. Valence (upper) and core-level (lower) XPS spectra for plutonium hydride. A valence band shift of over 2 e V toward higher energy is seen relative to the metal. The symmetric core-level 4f peaks are characteristic of the Pu ion with concomitant 6d screening. After Ward et al. (1992).

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