Turning Downtime Into Runtime: Breakthrough at SRS Improves Waste Cleanup

Savannah River Mission Completion is maximizing the runtime of the Salt Waste Processing Facility at the Savannah River Site by safely bypassing a piece of equipment, called the strip effluent coalescer, that used to cause downtime for frequent maintenance.

AIKEN, S.C. — The U.S. Department of Energy’s (DOE) Office of Environmental Management (EM) is operating a key radioactive waste processing facility more efficiently after making a breakthrough process change.

EM and Savannah River Mission Completion (SRMC), the liquid waste contractor at DOE’s Savannah River Site (SRS), are maximizing the runtime of the Salt Waste Processing Facility (SWPF) by safely bypassing a piece of equipment, called the strip effluent coalescer, that used to cause downtime for frequent maintenance. SWPF treats salt waste from the SRS waste tanks by removing cesium and other radionuclides.

The strip effluent coalescer is a small stainless steel vessel within SWPF that recovers the solvent used in the initial treatment step to separate the radioactive material from the waste. The coalescer media combines the solvent into large droplets so it can be easily removed from the waste stream, recovered and reused.

Pictured is the only part of the coalescer — the flange and coalescer media — that is visible; the coalescer vessel is inside a radiological cell.

Early in SWPF design, there was limited real‑world performance data for solvent management in the treatment process, so the facility designers added multiple layers of controls, one of which is using the coalescer to manage the solvent stream.

However, bypassing the strip effluent coalescer is possible now because actual operating data shows the required function is being met through other upstream controls. It’s the hardware that is bypassed, not the function.

Because of this improvement, the three-month average facility availability has jumped from 75% to 96%. Availability is the time that the system is “open for business” to process waste. The frequency of coalescer fouling-related maintenance has extended from approximately every 30 days to over 90 days, with the added benefit for planning quarterly integrated SRMC facility outages.

A close-up of the coalescer media.

SRMC President and Program Manager Thomas Burns Jr. said SRMC decided to bypass a design component to increase productivity after conducting the appropriate analysis and testing.

“This team is great at figuring out how to challenge the status quo, and optimize and streamline our process,” Burns said. “With that bias for action though comes the right amount of due diligence. Our nuclear engineers made sure the core functions of the strip effluent — managing solvent carryover and recovering solvent where practical — are still safely and reliably being met.”

-Contributor: Colleen Hart