Sol-gel microsphere pelletization process for fabrication of high-density ThO/sub 2/-2% UO/sub 2/ fuel for advanced pressurized heavy water reactors

Journal Article · Tue Apr 01 00:00:00 EST 1986 · Nucl. Technol.; (United States)

OSTI ID:5845662

Ganguly, C; Langen, H; Zimmer, E; Merz, E R

High-density ThO/sub 2/-2% UO/sub 2/ (/sup 233/U) pellets are a strong candidate fuel for advanced pressurized heavy water reactors. A process flow sheet based on sol-gel microsphere pelletization has been developed for the first time for fabrication of high-density mixed-oxide pellets at relatively low compaction pressures (350 MPa) and low sintering temperatures (1773 K). The process avoids handling or generation of radioactive dusts and is suitable for remote fabrication of highly radiotoxic /sup 233/U-bearing oxide fuels. The external gelation of thorium process of the Julich Nuclear Research Center has been used with three major modifications for preparation of ThO/sub 2/-UO/sub 2/ sol-gel microspheres, suitable for pelletization and sintering. First, a feed solution of lower molarity is used. Second, approx. = wt% calcium nitrate is added in the heavy metal nitrate feed solution in order to have approx. =0.4% CaO as a ''sintering aid'' in the subsequent mixed-oxide microspheres. Third, approx. =30 g/l carbon black are added in the sol prior to gelation. The pores formed in the sol-gel microspheres after burning off the carbon black particles reduce the crushing strength of the microspheres and facilitate pelletization. The sintered pellets thus prepared have high densities and uniformly distributed pores between 2 and 3 ..mu..m in size.

• Research Organization: Kernforschungsanlage Julich GmbH, Institut fur Chemische Technologie, D-5170 Julich
• OSTI ID: 5845662
• Journal Information: Nucl. Technol.; (United States), Vol. 73:1
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
36 MATERIALS SCIENCE
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
FUEL PELLETS
FABRICATION
MIXED OXIDE FUELS
THORIUM OXIDES
PELLETIZING
SOL-GEL PROCESS
URANIUM DIOXIDE
DENSITY
FLOWSHEETS
MICROSPHERES
PHWR TYPE REACTORS
SINTERING
URANIUM 233
VERY HIGH PRESSURE
VERY HIGH TEMPERATURE
ACTINIDE COMPOUNDS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
CHALCOGENIDES
DIAGRAMS
EVEN-ODD NUCLEI
FUELS
HEAVY NUCLEI
HEAVY WATER COOLED REACTORS
HEAVY WATER MODERATED REACTORS
ISOTOPES
MOLDING
NUCLEI
OXIDES
OXYGEN COMPOUNDS
PELLETS
PHYSICAL PROPERTIES
RADIOISOTOPES
REACTORS
SOLID FUELS
THORIUM COMPOUNDS
URANIUM COMPOUNDS
URANIUM ISOTOPES
URANIUM OXIDES
YEARS LIVING RADIOISOTOPES
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