Personnel perform measurements to ensure correct seating of a process gas filter bundle prior to the start of a recently completed confirmatory run of the Integrated Waste Treatment Unit at the DOE Idaho National Laboratory Site.
Personnel perform measurements to ensure correct seating of a process gas filter bundle prior to the start of a recently completed confirmatory run of the Integrated Waste Treatment Unit at the DOE Idaho National Laboratory Site.

IDAHO FALLS, Idaho – Following a record-breaking simulant run at EM’s Integrated Waste Treatment Unit (IWTU) earlier this summer, engineers are inspecting reaction vessels and other equipment of the liquid waste treatment facility before initiating radiological operations at the DOE Idaho National Laboratory Site, scheduled for this fall.

Joe Giebel, chief engineer for EM contractor Idaho Environmental Coalition (IEC), said he was pleased with the performance of IWTU as the facility operated continually for 62 days and converted approximately 137,000 gallons of liquid simulant to a granular solid — a record for the facility.

Of principal interest was the performance of the process gas filter (PGF), which filters gases from the Denitration Mineralization Reformer (DMR) — IWTU’s primary reaction vessel — through 18 filter bundles comprised of 342 individual filters. In prior demonstration runs, the PGF elements became restricted with corrosion products from the metallic filter degradation, causing limited operation of the IWTU or complete shutdown of the facility due to a rise in differential pressure.

For the most recent confirmatory run, engineers replaced the sintered metal filters with ceramic filters. Based on prior pilot plant testing at Hazen Research in Colorado, ceramic filters performed much better than their previous sintered-metal counterparts.

“The ceramic filters performed exceptionally well during the confirmatory run,” said Giebel. “Operators and engineers closely monitored filter performance throughout the 62-day run. The differential pressure across the filter bank remained stable and predictable.”

Based on the performance of the PGF for nine weeks, engineers believe the ceramic filters may not require replacing during the entire 900,000-gallon sodium-bearing waste treatment run.

Independent readiness verification assessments were conducted last month, a crucial step before moving toward radiological operations. The federal readiness assessment identified seven findings, some of which IEC had already identified and had been working to resolve.

“It’s exciting to see the project reach this point,” said Giebel. “The plant has never operated with a greater degree of reliability.”

The facility was constructed to process 900,000 gallons of radioactive liquid waste into dry granular solids that will be packaged in stainless steel canisters and stored in concrete vaults. The waste was generated during decontamination activities following spent nuclear fuel reprocessing.