Hanford’s TSCR system restarted after extended downtime

Earlier this week, the Tank-Side Cesium Removal (TSCR) system at the Department of Energy's Hanford Site near Richland, Wash., returned to service following a pause in operation that began on February 25.

The system, which produces low-level waste material by filtering radioactive cesium and solid materials from liquid waste, normally is available for a new treatment cycle about two weeks after a previous batch of waste has been processed. However, operators at Hanford decided against restarting the system in March, because Tank AP-106, which has been the storage receptacle for TSCR-processed material, was "too full" at the time to accept more LLW, according to the DOE.

A multistep treatment process: Vitrification-the process of converting radioactive and chemical substances to glass-is a technique used to clean up Hanford's 56 million gallons of tank waste. In some cases Hanford's high-level waste needs to be pretreated before vitrification to extract radionuclides like cesium-137 and other byproducts of plutonium production. Together, these byproducts are responsible for over 99 percent of the radioactivity in Hanford's legacy waste.

The TSCR system, which came on line in January 2022, accomplishes pretreatment by passing tank waste through ion exchange media rich in silica and titanium. These elements attract and filter out the cesium that otherwise would make the tank waste too hazardous for vitrification workers to handle and too expensive to safely store, according to Pacific Northwest National Laboratory.

Typically, the resulting LLW from the TSCR system is stored on-site at Hanford in Tank AP-106, a double-walled underground tank. From there, it is transferred to Hanford's Waste Treatment and Immobilization Plant (WTP), where since October 2025 the DOE's Office of Environmental Management and contractor Bechtel have been vitrifying LLW in the WTP's Low-Activity Waste (LAW) Facility. The final stage of the process is the permanent disposal of vitrified waste, which began at Hanford's Integrated Disposal Facility this past April.

However, earlier this year, Tank AP-106 was determined to contain too much LLW to receive additional waste from the TSCR system. The system's processes were then paused to allow time for operations at the LAW Facility to ramp up and accommodate some of the LLW. The TSCR system was restarted on September 15 after an extended downtime of just over six months.

A two-pronged strategy: When announcing that the TSCR system had resumed operations, DOE-EM noted that Tank AP-106 currently holds about 1 million gallons of waste that has been pretreated through the system. It also noted that more than 240,000 gallons of such waste has been transferred from Tank AP-106 to the WTP since vitrification commenced in October 2025.

To avoid future delays in the cleanup process, the DOE's Hanford Site offices have supported what they call a "dual glass-plus-grout" strategy. This would allow waste to be disposed of via grouting, which stabilizes LLW in a material similar to concrete, as well as being immobilized via vitrification.

According to Mat Irwin, assistant manager for tank waste operations at Hanford, "The restart underscores why Hanford is advancing a dual glass-plus-grout approach for appropriate treated waste streams . . . . Grout could add another disposal path to reduce bottlenecks and support continued cleanup progress."