Patent Number: 051788241
Section: claims

1. Apparatus for grinding nuclear fuel pellets including means for grinding the pellets in the presence of liquid, the improvement comprising a trough located below the grinding means for collecting liquid and grinding particulates therefrom, an outlet from the trough arranged to discharge said liquid and the grinding particulates into a vessel having declivitous sides and a bottom outlet, a collection chamber having an upper inlet communicable with the bottom outlet and having a lower outlet, a lower obturating means at the lower outlet, sensing means for sensing an accumulation of the grinding particulates at a predetermined level in the collection chamber, the lower obturating means being responsive to the sensing means, a recirculation circuit connected at one end to the declivitous sides of the vessel and having the other end thereof arranged to discharge at the grinding means, and pump means for circulating the liquid from the vessel through the recirculation circuit. 2. An apparatus as claimed in claim 1, further comprising upper obturating means between the sensing means and the bottom outlet, said upper obturating means being arranged to be opened when the lower obturating means is closed and to be closed when the lower obturating means is opened by the sensing means, and means for applying air pressure between the upper obturating means and the sensing means when the upper obturating means is closed and the lower obturating means is open. 3. An apparatus as claimed in claim 2, wherein a filter circuit is connected in the recirculation circuit for recirculating therethrough said liquid from the vessel. 4. An apparatus as claimed in claim 3, wherein the filter circuit includes the pump means connected in series therein. 5. Apparatus as claimed in claim 4, wherein the filter circuit includes cross-flow filter means. 6. Apparatus as claimed in claim 5, wherein a particulate coating applied to the cross-flow filter means inhibits rapid blocking of the cross-flow filter means. 7. Apparatus as claimed in claim 3, wherein a flush duct extends between the filter circuit and the trough so as to flush the trough with liquid from the vessel. 8. Apparatus as claimed in claim 5, wherein a through-flow outlet of the cross-flow filter means is connected so as to discharge into the vessel. 9. Apparatus as claimed in claim 5, wherein a filtrate outlet of the cross-flow filter means is connected so as to discharge through the recirculation circuit. 10. Apparatus as claimed in claim 6, wherein the coating comprises U.sub.3 O.sub.8. 11. Apparatus as claimed in claim 10, wherein the U.sub.3 O.sub.8 comprises particulates thereof having a size distribution between 45 and 90 microns and particulates thereof having a size distribution between 1 and 45 microns. 12. Apparatus as claimed in claim 11, wherein the U.sub.3 O.sub.8 particulates having said first mentioned size distribution and said second mentioned size distribution, respectively, are in the weight ratio of about 229 to 50.