Uraninite: A 2 Ga spent nuclear fuel from the natural fission reactor at Bangombe in Gabon, West Africa
Book
·
OSTI ID:572277
- Aarhus Univ. (Denmark). Dept. of Earth Sciences
- Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Earth and Planetary Sciences
- Centre National de la Recherche Scientifique, Strasbourg (France). Centre de Geochemie de la Surface
Uraninites from the Bangombe natural fission reactor (RZB) and normal uranium-ore occur as fine veins in the sandstone host-rock as well as altered, broken, and slightly displaced grains in an illitic matrix, and in nodules and veins of solid bitumen. Inclusions of galena, (Y,Gd)-rich phosphates, a Pb-oxide and a Ti-oxide? were observed. Uraninites just below RZB were partially altered to a uranyl-sulfate. Three generations of uraninite were identified based on their PbO-contents of 8--11.06 wt%, 6 wt% (the largest population), and a younger generation with 3 wt%. Diffusional loss of Pb is indicated by the presence of a Pb-oxide at the interface to the uraninites. The behavior of the metallic fission products, incompatible with the uraninite structure, may mimic the behavior of Pb in these uraninites. The averaged impurity-content ranges from 4.29 to 6.89 wt%, and consists mainly of SiO{sub 2}, TiO{sub 2}, ZrO{sub 2}, FeO, CaO, Al{sub 2}O{sub 3} and P{sub 2}O{sub 5}. The averaged content of Y{sub 2}O{sub 3} and the Ln`s is less than 0.78 wt% and there is a scattered positive correlation with P{sub 2}O{sub 5}. The content of Y + Ln`s is generally highest in the uraninites from RZB. Uraninite hydration and the formation of uranopelite/zippeite have caused complete loss of Y and the Ln`s. The analytical results indicate that Y and the Ln`s, which are high yield fission products, may be released from uraninite during alteration in the presence of P.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- OSTI ID:
- 572277
- Report Number(s):
- CONF-961202--
- Country of Publication:
- United States
- Language:
- English
Similar Records
Precipitation of uraninite in chlorite-bearing veins of the hydrothermal alteration zone (argile de pile) of the natural nuclear reactor at Bangombe, Republic of Gabon
The effects of water radiolysis on local redox conditions in the Oklo, Gabon, natural fission reactors 10 and 16
Mechanisms of lead release from uraninite in the natural fission reactors in Gabon
Conference
·
Sat Dec 30 23:00:00 EST 1995
·
OSTI ID:382900
The effects of water radiolysis on local redox conditions in the Oklo, Gabon, natural fission reactors 10 and 16
Journal Article
·
Fri Oct 31 23:00:00 EST 1997
· Geochimica et Cosmochimica Acta
·
OSTI ID:585491
Mechanisms of lead release from uraninite in the natural fission reactors in Gabon
Journal Article
·
Mon May 01 00:00:00 EDT 1995
· Geochimica et Cosmochimica Acta
·
OSTI ID:79272