The Nuclear Waste Vitrification Project was conducted to demonstrate the vitrification of high-level liquid waste (HLLW) generated during the reprocessing of spent fuel discharged from an operating light water reactor.Six pressurized water reactor fuel assemblies, containing 2.3 tU, were processed for the generation of HLLW. A conventional Purex-type process was used for the first cycle so that the HLLW generated would be typical of the nitric acid, fission product waste stream from the first extraction cycle of a commercial plant. Uranium and nonradioactive chemicals, normally added to the HLLW by back-cycling of waste from second and third solvent-extraction cycles, were added to the dilute HLLW to produce a waste composition typical of the HLLW from a commercial plant.Uranium and nonradioactive chemicals, normally added to the HLLW by back-cycling of waste from second and third solvent-extraction cycles, were added to the dilute HLLW to produce a waste composition typical of the HLLW from a commercial plant. The waste was then concentrated tenfold to provide feed for solidification by the spray calciner/in-can melting process. During calcination, the liquid waste was pumped at a rate of 10 to 15 ℓ/h to the calciner vessel, which was heated to 750°C. The powdered calcine fell into a stainless steel canister, which was maintained at 1050°C; this canister was attached directly to the bottom of the calciner. Glass-forming chemicals were metered into the canister simultaneously with the calcine. After the materials melted, the canister was cooled to produce vitreous glass. Two 20.3-cm-diam × 244-cm-high canisters containing glass were produced.

Six PWR fuel assemblies, containing 2.3 metric tons uranium from Point Beach, have been processed by a conventional Purex-type process. U and other chemicals were added to the dilute HLLW, and the waste was then vitrified to produce two canisters of glass. The on-stream efficiency of the waste preparation facility exceeded 90% for the first 3 weeks; the overall average was 62%. The only processing difficulty in the vitrification facility was a partial failure in the spray calciner nozzle. The Pu byproduct of waste preparation was purified by ion exchange and calcined to oxide; one can of oxide ruptured due to self-heating. 27 figures, 16 tables. (DLC)