Hanford's Material Sciences Laboratory has been demolished to ground level, leaving the landscape of the Hanford nuclear reservation's 300 Area just north of Richland looking much as it is expected to remain for at least a decade to come.
Demolition of the building, one of about 150 torn down by Washington Closure Hanford in the 300 Area, leaves the Department of Energy contractor with just two major buildings left to tear down there.
Rubble from the Material Sciences Laboratory, also called the 326 Building, is being hauled to the central Hanford landfill for low-level radioactive waste, and that work is expected to be completed by the end of the month. Washington Closure also is preparing to start below-grade work on the building, which should be completed by the end of the year, said Washington Closure spokesman Mark McKenna.
Still standing are several buildings that Pacific Northwest National Laboratory will continue to use, plus the 3790 Building and the 324 Building. Work is expected to begin in January to take down the 3790 Building, a large office building where badges were issued to Hanford visitors.
The 324 Building will be the last to be torn down by Washington Closure in the 300 Area after a spill of cesium and strontium was found beneath it. In 2010, Washington Closure discovered a crack in the sump at the bottom of one of the building's hot cells.
Washington Closure also has more below-ground structures to remove, including the Plutonium Recycle Test Reactor and the 340 Vault, each weighing an estimated 1,100 tons. They could be removed by the end of the year, weather permitting, said DOE spokesman Cameron Hardy.
DOE is required by the legally binding Tri-Party Agreement to have all excess 300 Area Buildings, except the 324 Building, removed by September 2015. Other work remaining includes digging up several miles of pipeline and multiple waste sites, Hardy said.
Preparations to demolish the 63,107-square-foot Material Sciences Laboratory started when workers moved out in 2011.
Among work done was characterization of 12 tritium storage tubes, each 12 feet long. Lead brick enclosures and a glovebox had to be stabilized and an irradiated fuel fragment removed from one of the gloveboxes. A network of trenches was filled with grout, and a furnace booth contaminated with cadmium was prepared for demolition.
The building opened in 1953 to support reactor development and originally was called the Pile Technology Building. It was used to experiment with spacing of fuel tubes and moderators in reactor cores for improved safety and efficiency, and also to examine reactor components and fuel elements.
The L-shaped building had offices along the outside and laboratories along the inside on two floors above ground. The basement contained large laboratories, large reactor mock-ups and graphite piles.
Because underground utilities must continue to serve a nearby building being used by Pacific Northwest National Laboratory, the Material Sciences Laboratory's below grade structure is not being removed beyond the top three feet.
Instead, the basement will be cleaned out, including removing two concrete and lead-lined hot cells, each measuring 12-by-12-by-8 feet. Then the basement will be filled with dirt.
When buildings used by the national lab come down, the remainder of the Material Sciences Laboratory also could be excavated.
w Annette Cary: 582-1533; email@example.com; Twitter: @HanfordNews