The assembly of the world's two largest melters to vitrify low-level waste at the US Department of Energy's Hanford Site has been completed ahead of schedule, Hanford announced last week.
Assembly of the first melter in the Waste Treatment and Immobilisation Plant's Low-Activity Waste (LAW) Facility was finished in May, and assembly of the second in August.
Each melter is about 20ft x 30ft and 16ft high, weighing 300t. It is composed of a base and walls, off-gas barrier and radiation shield lids, a refractory interior made of high-heat resistant bricks, and other components to feed, mix, and monitor the glass mixture.
“The scale and complexity of these radioactive waste melters are unparalleled," said Bill Hamel, ORP’s federal project director for the Waste Treatment Plant. "Each is the largest of its kind ever built in the USA; and when we begin making glass, will be the largest in operation in the world.”
The melters will be used to heat Hanford's low-activity tank waste and glass-forming materials to 2100F as part of the vitrification process. Each melter can produce 15t of vitrified waste per day. If both melters operate at full capacity they will be able to fill over 1100 containers a year.
"With the melters assembled and all major process equipment already installed, our workforce remains on pace toward the construction complete contract milestone of June 2018 for the Low Active Waste Facility," said Peggy McCullough of Bechtel National, which installed the melters under an $8.5m contract.
The melters will be tasked with processing 56 million gallons of radioactive waste that is stored in tanks at the Hanford Site. The schedule currently envisages the start of vitrification in 2022.
Meanwhile, workers at Hanford are in the process of injecting grout into the tunnel that partially collapsed earlier this year. Contractor CH2M Hill Plateau Remediation Company plans to complete the filling of the tunnel by the end of December. There was no spread of contamination after the partial tunnel collapse in May. The tunnel was one of two built in the 1950s and 1960s to hold contaminated equipment from plutonium production activities. The tunnel is full of train cars containing radioactive waste. Experts at the site say the best solution is to fill it up with grout.
