The Hanford 100 Area is a 26-square-mile piece of land along the Columbia River where nine water-cooled plutonium reactors were constructed between 1943-1963. There are six reactor areas (three of which contain two reactors each and three that contain one reactor each) in the 100 Area. All nine reactors were operating at one point during the early 1960s, but only N Reactor (which produced both plutonium and electricity) remained in operation after 1971.

One of the major cleanup priorities in the 100 Area is the K Basins, located adjacent to the K West and K East reactors. More than 2,315 tons of spent nuclear fuel, or nearly 80 percent of USDOE’s nationwide reserve, was stored in these concrete basins. Located a few hundred meters from the Columbia River, the 40-year-old basins do not meet current safety standards, and one has leaked several times in the past. All of the fuel has been removed and sent to the Central Plateau for storage.

The fuel resided in the basins for decades and deteriorated. Some of the material formed a sludge on the bottom of the basins. Sludge removal is ongoing and the basins are expected to be drained in the next several years.

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