Reduction of UO22+ by H-2
2004 (English)In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 334, no 1, 35-39 p.Article in journal (Refereed) Published
The reactivity of H, towards UO22+ has been studied experimentally using a PEEK coated autoclave where the UO22+ concentration in aqueous solution containing 2 mM carbonate was measured as a function of time at p(H2) similar to 40 bar. The experiments were performed in the temperature interval 74-100 degreesC. In addition, the suggested catalytic activity of UO2 on the reduction of UO22+ by H-2 was investigated. The results clearly show that H-2 is capable of reducing UO22+ to UO2 without the presence of a catalyst. The reaction is of first order with respect to UO22+. The activation energy for the process is 130 +/- 24 U mol(-1) and the rate constant is k(298K) = 3.6 x 10(-9) l mol(-1) s(-1). The activation enthalpy and entropy for the process was determined to 126 kJ mol(-1) and 16.5 J mol(-1) K-1, respectively. Traces of oxygen were shown to inhibit the reduction process. Hence, the suggested catalytic activity of freshly precipitated U02 on the reduction of UO22+ by H-2 could not be confirmed.
Place, publisher, year, edition, pages
2004. Vol. 334, no 1, 35-39 p.
IdentifiersURN: urn:nbn:se:kth:diva-23680DOI: 10.1016/j.jnucmat.2004.04.324ISI: 000223548400005ScopusID: 2-s2.0-3343018403OAI: oai:DiVA.org:kth-23680DiVA: diva2:342379
QC 20100525 QC 201109232010-08-102010-08-102011-09-23Bibliographically approved