IDAHO FALLS, Idaho – Fluor Idaho, the new cleanup contractor at EM’s Idaho Site, is using a Colorado technology research and development facility to help resolve complex challenges related to the initiation of liquid waste treatment operations at the Integrated Waste Treatment Unit (IWTU).
Hazen Research, near Golden, has been used as a technology testing ground since 1961. The independent research facility will soon use its fluidized bed technology to demonstrate new control strategies and refine operating conditions to correct problems experienced at IWTU — instabilities and unexpected temperature gradients of the fluidized bed along with the formation of scale deposits on the internal surfaces of the treatment vessel.
The IWTU is intended to treat 900,000 gallons of radioactive liquid waste at the Idaho Site using a steam reforming process. The process converts the liquid waste, consisting of hazardous chemicals, radioactive constituents, and heavy metals, to a dry, granular product. During the process, the primary treatment vessel is heated up to 1,700 degrees Fahrenheit. Liquid waste is sprayed into a reaction chamber filled with tiny beads that are kept in motion, or fluidized, with a combination of gases such as nitrogen, steam and oxygen.
As the liquid dries, the residue solidifies onto the surfaces of tiny beads, similar to the creation of a pearl. Gases produced during this process are captured in a series of filters to ensure the plant emissions meet state air quality standards. The dried product is then transferred to stainless steel canisters and placed within concrete vaults for on-site storage until a national geologic repository is available to accept the waste.
The IWTU has been tested four times using a waste simulant that resembles the actual waste that it was built to treat. During each test, the instabilities appeared periodically during the testing, and scale deposits were formed on the interior walls of the treatment vessel. The last waste simulant run, which took place in May, incorporated a series of recommendations from technical experts who attended a Chemistry Summit and Fluidized Bed Workshop held earlier this year in Idaho Falls. Significant improvements were observed regarding the quality of the product and the amount of scale was reduced. The remaining challenges relate to instabilities during operations and temperature gradients.
Fluor is working with national laboratories, industry experts and Hazen Research to assess and demonstrate new control strategies and refine operating conditions for the plant. Testing at the Hazen facility will use a small-scale fluidized bed reactor similar to the treatment vessel at IWTU and will utilize the waste simulant that the Idaho facility has been using during its four prior testing campaigns. Fluor and Hazen engineers will test different conditions to assess the effectiveness of the new control strategies and assess potential adjustments that could be made to the IWTU to improve its operation. Information gained from the Hazen testing will be used for the next waste simulant run at IWTU.