Temporary storage proposed for vit plant waste

Hanford contractor officials are proposing a temporary storage system for Hanford's treated high-level radioactive waste that easily can be expanded, given uncertainties about the nation's plans for a national waste repository.

Washington River Protection Solutions formed an independent review team that is recommending a new Hanford building large enough to store as much high-level radioactive waste as the Hanford vitrification plant is expected to treat in a decade. But if needed, more vaults could be added.

The initial plans do not include a shipping facility. Given austere federal budget conditions, it makes sense to wait to add that when the nation is ready to ship the waste, said Tom Fletcher, Department of Energy acting assistant manager of the Hanford tank farms.

Hanford has 56 million gallons of radioactive and hazardous chemical waste in underground tanks awaiting treatment. That includes high-level radioactive waste that DOE plans to turn into a stable glass form at the vitrification plant starting in 2019.

The treated high-level waste then was planned to be shipped to the proposed Yucca Mountain, Nev., repository, but DOE has shut down work on the project, and the Blue Ribbon Commission on America's Nuclear Future is considering what the nation should do with its high-level radioactive waste.

The vitrification plant has space to let the treated waste cool from the high temperatures of the plant's melters, but then it must be moved to temporary storage off the plant's grounds to allow treatment of waste to continue.

A temporary storage system had been planned at Hanford before the shutdown of the Yucca Mountain project, but with plans for a national repository uncertain now, the waste is expected to remain at Hanford longer.

The review team considered the cost and functionality of four proposed storage systems, before settling on a building with below-ground storage for 4,000 canisters of immobilized waste. The vitrification plant will produce canisters of glassified waste weighing four tons and measuring 15-foot long and two feet in diameter.

The building would have two below-ground vaults to store the canisters on open racks, each vault with a trolley crane to move the canisters in and out. A ventilation system using HEPA filters would be needed to provide cooling as radioactivity decays.

The proposed building is planned initially to measure 218 feet wide, 300 feet long and 50 feet wide, which should hold the vit plant's production for a decade. But it will be designed to allow additional vaults to be added.

The preliminary estimate of the proposed building's cost is between $150 million and $200 million. It would be built just north of the vitrification plant.

The Washington State Department of Ecology, the regulator on the project, is pleased to see plans being made since the building needs to be ready to accept waste in 2019, said Suzanne Dahl, waste treatment section manager for the state.

The conceptual design is expected to be completed in April and the building is expected to be ready to operate in August 2018, according to Washington River Protection Solutions. That will require an aggressive schedule to get the needed permits in place, said Curt Rieck, the contractor's project manager, in a statement.

The state will be looking for a robust design as it issues permits for the projects, because of delays expected in getting the waste shipped off site, Dahl said.

The review team also considered retrofitting unused space at Hanford's Canister Storage Facility, but that would only provide space for the vit plant's output of glassified high level waste for about two years. In addition workers there would need additional security clearance because of other materials stored in that complex.

A second option considered was storing the waste canisters in specially built casks on outdoor pads, similar to the system for used nuclear fuel at Energy Northwest's commercial nuclear power plant near Richland. But the cost of the many casks that would be needed over the years was prohibitive, Fletcher said.

It also looked at a system similar to the one used at the Savannah River, S.C., nuclear site, which stores waste below ground in closed racks by dropping it into grouted tubes, Fletcher said. That would have required more space than an open rack system.

The vitrification plant also will glassify low activity radioactive waste, but only high level radioactive waste is required by law to be sent to a national repository. The treated low activity waste it will be disposed of at a landfill built for that purpose, Hanford's Integrated Disposal Facility.

-- Annette Cary: 582-1533; acary@tricityherald.com; more Hanford news at hanfordnews.com.