Weather permitting, the blast will go off at 7 a.m. Saturday but it will be unspectacular.
Washington Closure program manager Chris Pearson says there may be a bit of dust. The walls are underground and a blast mat has been placed over the opening.
The Tri-City Herald reports the Plutonium Recycle Test Reactor was built in the 1950s. The reactor was lifted out in January and buried at a Hanford landfill.
Most of the Hanford cleanup along the Columbia River is expected to be completed next year.