METHOD OF PREPARING A FUEL ELEMENT FOR A NUCLEAR REACTOR

Patent · Sun Jan 01 04:00:00 EST 1961

OSTI ID:4111754

An economical method for fabricating UO/sub 2/-ThO/sub 2/ ceramic fuel elements consists of mixing finely divided U/sub 3/O/sub 8/ or UO/sub 3/ with ThO/ sub 2/, pressing the mixture to form a body of the desired size and shape, and firing the body in air at a tem perature between 1450 deg C and the fusion point of the misture. At this high temperature, U/sub 3/O/sub 8/ and/or UO/sub 3/ decomposes to UO/sub 2/, and the internal stresses resulting from the shrinkage or voids are relieved without cracking. A number of such bodies were prepared and examined; those containing up to 30 wt.% U/sub 3/O/sub 8/ were free of visible defects, whereas those containing 30 to 70 wt% UO/sub 2/ were somewhat cracked but deemed satisfactory for reactor use. Irradiation tests were carried out on similar bodies containing 2.5 and l0% UO/sub 2/ in reactor neutron fluxes of 2 x 1O/sup 13/ to 4 x 1O/sup 14/ neutrons/cm/sup 2// sec and in pressurized water and NaK environments; after extensive irradiation, the bodies were found intact, although a few had fragmented and others contained microscopic cracks. Fuel elements containing 6.6 wt.% U/sub 3/O/sub 8/ enriched 90% in U/sup 235/ were prepared in the above manner and are now used in the Borax IV reactor. (D.L.C.)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-15-007741
• OSTI ID: 4111754
• Report Number(s): GB 857672
• Country of Publication: United Kingdom
• Language: English

Related Subjects

BORAX-4
CERAMICS
COMPACTING
CRACKS
DECOMPOSITION
DEFECTS
DEFORMATION
ENVIRONMENT
EUTECTICS
FABRICATION
FUEL ELEMENTS
GASES
HEATING
IRRADIATION
METALS, CERAMICS, AND OTHER MATERIALS
MIXING
NEUTRON FLUX
POTASSIUM ALLOYS
PYROLYSIS
REACTORS
SHRINKAGE
SODIUM ALLOYS
STRESSES
TESTING
THORIUM OXIDES
U3O8
URANIUM DIOXIDE
URANIUM TRIOXIDE
VOIDS
WATER