The first of two 300-ton melters that will vitrify mixed low-level radioactive and chemical tank waste is heating up at the U.S. Department of Energy’s (DOE’s) Hanford Site in Washington. Initiating and completing the heating of the melter is a critical step to commissioning Hanford’s Waste Treatment and Immobilization Plant (WTP), which will treat and stabilize the site’s 56 million gallons of tank waste by immobilizing it in glass through the vitrification process.

The DOE estimates that several weeks may be needed to finish heating up the melter to its commissioning and operational temperature of 2,100° F. The melters, each measuring about 20 ft by 30 ft and 16 ft high, are part of the WTP's Low-Activity Waste facility.

The comprehensive process for heating up the first melter will ensure the temperature increases slowly and insulation inside the melter dries out slowly. Temporary startup heaters have been inserted into the top of the systems, and glass beads, called frit, will be added. As the beads melt and a molten glass pool rises to cover electrodes inside the device, its permanent heating equipment will take over to maintain the operational temperature.

After heating up, the first melter will remain active using nonradioactive materials, and lessons learned from the first melter will be used to begin the process to heat up and commission the second. When both melters are at operating temperature, the facility will run simulated waste through them as they continue preparations to vitrify waste.

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