Decomposition kinetics of plutonium hydride
Kinetic data for decomposition of PuH/sub 1/ /sub 95/ provides insight into a possible mechanism for the hydriding and dehydriding reactions of plutonium. The fact that the rate of the hydriding reaction, K/sub H/, is proportional to P/sup 1/2/ and the rate of the dehydriding process, K/sub D/, is inversely proportional to P/sup 1/2/ suggests that the forward and reverse reactions proceed by opposite paths of the same mechanism. The P/sup 1/2/ dependence of hydrogen solubility in metals is characteristic of the dissociative absorption of hydrogen; i.e., the reactive species is atomic hydrogen. It is reasonable to assume that the rates of the forward and reverse reactions are controlled by the surface concentration of atomic hydrogen, (H/sub s/), that K/sub H/ = c'(H/sub s/), and that K/sub D/ = c/(H/sub s/), where c' and c are proportionality constants. For this surface model, the pressure dependence of K/sub D/ is related to (H/sub s/) by the reaction (H/sub s/) reversible 1/2H/sub 2/(g) and by its equilibrium constant K/sub e/ = (H/sub 2/)/sup 1/2//(H/sub s/). In the pressure range of ideal gas behavior, (H/sub s/) = K/sub e//sup -1/(RT)/sup -1/2/ and the decomposition rate is given by K/sub D/ = cK/sub e/(RT)/sup -1/2/P/sup 1/2/. For an analogous treatment of the hydriding process with this model, it can be readily shown that K/sub H/ = c'K/sub e//sup -1/(RT)/sup -1/2/P/sup 1/2/. The inverse pressure dependence and direct temperature dependence of the decomposition rate are correctly predicted by this mechanism which is most consistent with the observed behavior of the Pu--H system.
- Research Organization:
- Atomics International Div., Golden, CO (USA). Rocky Flats Plant
- DOE Contract Number:
- EY-76-C-04-3533
- OSTI ID:
- 6233953
- Report Number(s):
- RFP-2878; CONF-790641-1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ACTINIDE COMPOUNDS
ACTINIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DECOMPOSITION
ELEMENTS
HYDRIDATION
HYDRIDES
HYDROGEN COMPOUNDS
KINETICS
METALS
PLUTONIUM
PLUTONIUM COMPOUNDS
PLUTONIUM HYDRIDES
PRESSURE DEPENDENCE
REACTION KINETICS
TRANSURANIUM COMPOUNDS
TRANSURANIUM ELEMENTS