In about three weeks, the control tower outside Washington State University Tri-Cities' new laboratory will grow to 90 feet tall.
The laboratory was built by EnergySolutions to test mixing of high-level radioactive waste within the large tanks inside the Hanford vitrification plant's Pretreatment Facility.
EnergySolutions, which has a Bechtel National subcontract for the testing, donated the new lab to the university in August 2012 and is leasing it back until most testing is completed.
The tower, on Q Avenue off of University Drive in north Richland, now is 75 feet tall but will be topped with a control hut in the coming weeks. Operators in the hut will monitor and control a test mixing system within a tank inside the lab.
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The tower and other equipment at the test lab are designed to geometrically mimic conditions at the Pretreatment Facility, where high-level radioactive waste must be kept well mixed in tanks. A buildup of waste could lead to an uncontrolled nuclear reaction or the combustion of hydrogen gas, both unlikely events, officials say.
Construction now is stopped on the Pretreatment Facility until mixing and other technical issues are resolved. It's part of the $12.3 billion Hanford plant planned to turn up to 56 million gallons of radioactive waste, left from weapons plutonium production, into a stable glass form for disposal.
To limit the need for maintenance or repairs, pulse jet mixers -- a mixing system with nonmoving parts -- are planned to keep waste mixed in the tanks in the Pretreatment Facility. Pulse jet mixers will work like giant turkey basters in the tanks, sucking up waste and then shooting it back out to disperse the solids as they start to settle in the tank.
The control hut, with valves and electronic equipment, will be higher than the tanks inside the test lab, just as the controls at the Pretreatment Facility will sit above the tanks there.
"We wanted to emulate all aspects of the design -- pipeline length, elevation, diameters," said Langdon Holton, DOE senior technical authority for the vitrification plant, as some members of the Hanford Advisory Board toured the lab Wednesday.
On the ground outside the lab sit tanks of compressed air that will be piped from the tower to pulse jet mixers in a 13-foot diameter, 16-foot-tall tank within the lab's high bay.
In the first of three phases of testing to be done over about three years, the control system of the pulse jet mixers will be tested. The testing is expected to begin in a few months using a nonradioactive simulant of Hanford's waste. It will continue with mock waste mixtures that become progressively more difficult to keep mixed.
To test the limits of the system, the lab has some air piping that includes bends, and some of the piping from the control hut to the tank in the lab is nearly horizontal.
As the first phase of testing is mostly completed, the piping and tank will be used to demonstrate the effectiveness of equipment being considered for periodic inspection at the vitrification plant to evaluate metal components. Concerns have been raised that over 40 years of operation, metal at the vit plant could erode or corrode.
At the same time work is being done at the WSU lab -- which is called both the EnergySolutions Engineering Laboratory and the Full Scale Vessel Test Facility -- work also will be done at Mid-Columbia Engineering in Richland.
The commercial facility will be used to make decisions on a new tank design after DOE announced a plan to replace eight proposed tanks at the Pretreatment Facility with up to 16 smaller, uniform tanks that could keep waste mixed better. All of the tanks would not be used when the Pretreatment Facility begins operating, giving it some extra tanks in case of problems in areas of the plant too radioactive for workers to enter for repairs.
After a final tank design is selected and a tank manufactured, the third phase of testing would resume at the WSU lab. Former Energy Secretary Steven Chu committed to mixing tests using a full-scale tank to resolve technical issues and give confidence in the design.
The lab has a skylight to allow the tank that will be used initially for testing to be lifted out and replaced with the new tank.
-- Annette Cary: 582-1533; firstname.lastname@example.org; Twitter: @HanfordNews