Mock-up Training Benefits High-Priority ORNL Cleanup Project

An Isotek employee wearing a protective suit implements lessons learned from recent training to replace equipment inside a hot cell. These upgrades support future processing operations for the Uranium-233 Disposition Project at Oak Ridge National Laboratory.

OAK RIDGE, Tenn. — How can employees safely perform repairs inside highly contaminated rooms used to process nuclear waste?

That’s a question Oak Ridge Office of Environmental Management (OREM) contractor Isotek is answering through advanced training that is helping prepare and protect employees while also facilitating efficient operations to keep Oak Ridge National Laboratory’s (ORNL) highest priority cleanup project on track.

OREM and Isotek are working to eliminate the nation’s inventory of uranium-233 (U-233) from storage at ORNL.

U-233 presents risks and is costly to keep safe and secure. Originally created in the 1950s and 1960s for potential use in reactors, it proved to be an unviable fuel source.

The remaining inventory of U-233 stored onsite requires processing to convert it into a form safe for shipment and permanent disposal. That work involves Isotek employees placing the material in heavily shielded rooms, called hot cells, and handling that material using mechanical arm manipulators.

Equipment used inside the hot cells degrades over time from wear and tear and from high radiological dose. To replace the equipment, workers must occasionally enter the hot cells.

“The hot cells are heavily contaminated from the highly radioactive material we process within them,” Isotek Radiological Control Manager Rodney Bauman said. “We want to be inside hot cells as little as possible.”

Inside a mock-up, Isotek employees practice the steps involved in replacing hot cell equipment. The mock-up features the exact dimensions of an actual hot cell.

Entries occur approximately five times a year — only when equipment inside the rooms cannot be fixed or replaced using the openings in the hot cells.

Isotek is preparing employees for those entries by providing them opportunities to dress in personal protective equipment and practice tasks before performing them in high radiation areas. Radiological control, maintenance and engineering teams fabricated a mock-up hot cell offsite so key personnel could perform and perfect hot cell entry procedures before ever entering the hazard zone.

“The idea behind the mock-up hot cell is that we can get comfortable performing our work in all the additional layers of personal protective equipment so that when we enter the real hot cell, we’re able to perform our work more efficiently,” Bauman said. “This is a great way to help keep our workers safe.”

The mock-up was constructed to the exact measurements of a hot cell so workers can adapt to the dimensions of the limited space. Staff must learn to perform tasks with minimal contact with surfaces and equipment inside, which helps them avoid areas with high levels of contamination and reduce the likelihood of spreading contamination.

This training is especially timely because these rooms are becoming more contaminated as crews process material from the inventory with increasingly higher levels of radiation.

Hot cell entries also provide an opportunity to make improvements to the processing system.

“We know a lot more about the layout needed in the hot cell now than we did when we first started,” Isotek Process Engineer Jesse Jensen said. “We were able to redesign some of the equipment to take better advantage of the space and hopefully make it last longer, while also making it easier to replace and maintain in the future.”

The hot cell mock-up practice has already paid off.

In recent weeks, Isotek workers entered one of the hot cells and replaced all the processing equipment inside. The activity involved loosening and fastening hose lines, lifting and replacing ion-exchange columns stands, and the challenging process of communicating to personnel outside the hot cell using radios in their protective suits.

The hot cell entry was safe and successful with new and improved equipment installed to support future processing operations.

Isotek is coming off a successful 2024 campaign. Employees processed more than 90 canisters of high-dose material last year, exceeding the goal of 35. They also continued extracting medical isotopes from the U-233 material to support next-generation cancer treatment research.

-Contributor: John Gray