METHOD OF IRRADIATED BORON CARBIDE PROCESSING Russian patent published in 2000 - IPC

FIELD: nuclear technology. SUBSTANCE: adsorbing core in the form of tablets or tablet fragments or boron carbide powder is removed from depleted control rods of nuclear reactor, deactivated from radionuclide surface contamination, then tritium is removed, chlorinated to boron trichloride BCl₃, hydrolyzed to yield boric acid H₃BO₃ or boron anhydride B₂O₃ and reduced to boron carbide B₄C. Core is removed by cutting envelope and its dissolving in acids or by its ejection at envelope heating to 600 C. Tritium is removed by heating irradiated boron carbide under vacuum to 800-2000 C followed by exposition in the presence of getter Zr, Ti, Hf. Chlorination is carried out at 850-1000 C at the rate of chlorine flow 1 m/s, not above, and at consumption 9-15 g/g of boron carbide. Hydrolysis is carried out by passage of BCl₃ through distilled water followed by evaporation of the solution. Reduction of B₄C is carried out by carbonthermic method at 1680 ± 20 C. EFFECT: enhanced effectiveness of expensive enriched boron carbide using. 6 cl, 1 ex