IDAHO FALLS, Idaho – Modifications are complete to two of the reaction vessels of the Integrated Waste Treatment Unit (IWTU), and crews are re-assembling the facility’s components in preparation for the next demonstration run this spring at EM's Idaho Site. The IWTU is designed to treat 900,000 gallons of liquid waste stored in underground tanks at the site.
While most of the attention ahead of the demonstration run had been on modifying the sodium-bearing waste treatment facility’s primary reaction vessel – the Denitration Mineralization Reformer (DMR) – IWTU crews also replaced the Carbon Reduction Reformer’s (CRR) refractory, or insulation material, which protects the vessel’s outer wall from extreme heat while operating. The insulation was replaced with a brick-like material, which is expected to fare much better during the facility’s heat cycles.
The CRR, which operates at 1750 degrees Fahrenheit, converts organics in the liquid waste material to carbon monoxide and carbon dioxide. Additionally, it converts the nitrogen oxide generated during waste treatment to nitrogen, further reducing any emissions.
Fluor Idaho Force Account welders earlier modified the shape of the DMR. Based on computer modeling and testing at Hazen Research Inc., in Colorado, engineers had determined the shape of the DMR was not conducive to optimum waste treatment and actually hampered the fluidization of billions of tiny beads necessary to convert liquid waste to a granular solid. The bottom of the DMR was redesigned to an inverted cone from its previous, half-moon shape.
Like previous demonstration runs at IWTU, a waste simulant resembling radioactive liquid waste at the Idaho Nuclear Technology and Engineering Center’s tank farm will be used to test the IWTU’s processes. In the next run, scheduled to begin in late March, phosphoric acid will be added to the simulant to minimize the chance of wall scale – a bark-like material – from forming on the inside of the DMR. The wall scale disrupts the fluidization process.
The demonstration run is expected to be the longest for the IWTU, totaling approximately 80 days, and consisting of a fluidization test and a subsequent waste feed rate and particle size test.