Methods for assessing homogeneity in ThO/sub 2/--UO/sub 2/ fuels (LWBR Development Program)

Technical Report · Thu Jun 01 04:00:00 EDT 1978

DOI:https://doi.org/10.2172/6722562· OSTI ID:6722562

Berman, R. M.

ThO/sub 2/-UO/sub 2/ solid solutions fabricated as LWBR fuel pellets are examined for uniform uranium distribution by means of autoradiography. Kodak NTA plates are used. Images of inhomogeneities are 29 +- 10 microns larger in diameter than the high-urania segregations that caused them, due to the range of alpha particles in the emulsion, and an appropriate correction must be made. Photographic density is approximately linear with urania content in the region between underexposure and overexposure, but the slope of the calibration curve varies with aging and growth of alpha activity from the parasitic /sup 232/U and its decomposition products. A calibration must therefore be performed using two known points--the average photographic density (corresponding to the average composition) and an extrapolated background (corresponding to zero urania). As part of production pellet inspection, plates are evaluated by inspectors, who count segregations by size classes. This is supplemented by microdensitometer scans of the autoradiograph and by electron probe studies of the original sample if apparent homogeneity is marginal.

• Research Organization: Bettis Atomic Power Lab., West Mifflin, PA (USA)
• DOE Contract Number: EY-76-C-11-0014
• OSTI ID: 6722562
• Report Number(s): WAPD-TM-1377
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210500* -- Power Reactors
Breeding
ACTINIDE COMPOUNDS
AUTORADIOGRAPHY
BREEDER REACTORS
CHALCOGENIDES
CONTROL
FABRICATION
FUEL PELLETS
LWBR TYPE REACTORS
OXIDES
OXYGEN COMPOUNDS
PELLETS
QUALITY CONTROL
REACTORS
THERMAL REACTORS
THORIUM COMPOUNDS
THORIUM OXIDES
URANIUM COMPOUNDS
URANIUM DIOXIDE
URANIUM OXIDES
WATER COOLED REACTORS
WATER MODERATED REACTORS