N Reactor at Hanford mothballed

YAKIMA – Workers at south-central Washington’s Hanford Nuclear Reservation have finished the process of closing and “cocooning” the longest-running of nine nuclear reactors built there for the U.S. atomic weapons program.

With the completion of work at N Reactor, six reactors at the nation’s most contaminated site have been dismantled and cocooned. That involved removing extra buildings around the reactors, demolishing all but the shield walls surrounding the reactor cores and sealing them in concrete.

Much work remains to be done, but the conclusion of the $65 million project marks a historic moment. Some 37,000 people traveled to Hanford on Sept. 26, 1963, to see President John F. Kennedy dedicate N Reactor next to the Columbia River, noting its role in changing “the entire history of the world.” The reactor operated until 1987.

N Reactor was unique because it operated on a closed-loop cooling system. That enabled the reactor to recirculate water for cooling, which led to less river contamination, and to produce steam for electricity, making it the only dual-purpose reactor in the U.S.

Work still to be completed along Hanford’s scenic river corridor includes two reactors, K East and K West, which must be permanently closed up and cocooned; many waste sites and contaminated soil need to be dug up; and tainted groundwater must be treated.

The Energy Department planned to complete much of that work by 2015 in hopes of shrinking the overall footprint of the Hanford site. But hundreds of new waste sites have been uncovered in recent months and could delay that effort.

“Completing the cocooning process is the culmination of years of detailed planning and safe, disciplined operations by workers dedicated to protecting one another, the environment and the river,” said Carol Johnson, president of the contractor handling the work, Washington Closure Hanford.