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 04:00:00 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), Journal Name: Nucl. Technol.; (United States) Vol. 73:1; ISSN NUTYB
• Country of Publication: United States
• Language: English

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