West Valley Tank 8D-1 and 8D-2 Inventory Estimation Methodology

Abstract

This report details work funded by the West Valley Support Project (WVSP) and the Tanks Focus Area Retrieval and Closure Program. The work was conducted by the Pacific Northwest National Laboratory (PNNL) and is in support of the West Valley Demonstration Project (WVDP). The WVDP site in New York was originally the site of a commercial nuclear fuel reprocessing plant. The high-level waste (HLW), approximately 2 million liters, produced during plutonium-uranium extraction (PUREX) and thorium extraction (THOREX) reprocessing campaigns at the plant and subsequent HLW preprocessing, was stored on site in three tanks identified as 8D-1, 8D-2, and 8D-4. Waste from the PUREX process was neutralized with NaOH for storage in a carbon steel tank designated as 8D-2. Neutralization resulted in a precipitated hydroxide sludge that settled to the bottom of the tank and was covered by a supernatant salt solution. The acidic THOREX waste, approximately 55,000 L, was first stored in a stainless steel tank (8D-4) and then added to the PUREX waste in Tank 8D-2. Supernatant decontamination, primarily cesium removal, was conducted by ion-exchange using in-tank columns suspended in Tank 8D-1. The cesium-loaded zeolite, resulting from the supernatant decontamination process, was dumped to the bottom of Tank 8D-1. Approximately 90% of the spent zeolite was transferred from Tank 8D-1 into Tank 8D-2 by the start of vitrification processing in June 1996. Periodically, the remaining spent zeolite contained in Tank 8D-1 is incrementally transferred to 8D-2. The combined waste in Tank 8D-2 continues to be processed through the Vitrification Facility into canisters for final repository disposal.