Generation and Vitrification of High-Level Light Water Reactor Liquid Waste

Abstract

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 at 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. 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 to the calciner vessel, which was heated to 750/sup 0/C. The powdered calcine fell into a stainless steel canister, which was maintained at 1050/sup 0/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 producemore » glass. Two canisters containing glass were produced.« less