Method of controlling the crystal grain size of uranium dioxide pellet
US4873031A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 30, 1987 |
| Grant date | Oct 10, 1989 |
| Priority date | — |
| Expiry date | Dec 30, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/10
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method of controlling the crystal grain size of UO.sub.2 pellets is disclosed, which comprises PA1 (1) providing an aqueous uranyl solution which is free of hydrofluoric acid and nitric acid and which contains uranyl fluoride (UO.sub.2 F.sub.2) and/or uranyl nitrate (UO.sub.2 (NO.sub.3).sub.2) as a uranium component, PA1 (2) reacting with ammonia said aqueous uranyl solution to precipitate ammonium diuranate (ADU), while adjusting the ratio of said uranium components to a predetermined value within the range varying from the ratio 100% of uranyl fluoride and 0% of uranyl nitrate to the ratio 0% of uranyl fluoride and 100% of uranyl nitrate, adjusting the uranium concentration of the reaction mixture to 50 to 1,000 gU/liter and also adjusting the rate of contact between said uranium component in said aqueous uranyl solution with ammonia to at least 2 moles NH.sub.3 /min/mole U, PA1 (3) calcining and reducing said ADU precipitate to form UO.sub.2 powder, and PA1 (4) molding and sintering said UO.sub.2 powder, thus producing UO.sub.2 pellet having a predetermined crystal grain size in the range varying from 5 to 100 micrometers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.