When the decision to stop producing plutonium at Hanford was made in the late 1980’s, there were more than 100,000 uranium fuel rods and rod fragments that had been irradiated in Hanford’s N Reactor, but would not be processed any further. In other words, these fuel rods would not have their plutonium extracted from them. Subsequently, these fuel rods needed to be stored until the decision was made about where these rods would ultimately end up.
It was determined that these fuel rods would temporarily be placed in two, water-filled storage areas adjacent to the K-East and K-West Reactors. Called the K-Basins, each of these basins contained about 1,000,000 gallons of water, and they were located about 400 yards from the Columbia River.
The K-Basins were built in the 1950’s, and at that time, they were built for a 20-year mission. The basins were already beyond their anticipated service life when these fuel assemblies were placed in them, and the basins were not built to store spent nuclear fuel for decades as they had to. By the 1990’s, it was discovered that the K-East Basin had started to leak contaminated water into the ground. Additionally, the fuel rods in both basins had started to deteriorate, resulting in the formation of a material called “sludge”. This sludge consisted of tiny fuel corrosion particles, fuel rod fragments, metal fragments, wind-blown sand, and other materials. As long as the water wasn’t disturbed, crews could see the sludge which sat in a gray layer on top of the other wastes within the basins. However, whenever the water was disturbed, the sludge would become mobile. It would make the water so cloudy that no one could see into it, just as ocean water becomes brown when the waves crash onto the beach and disturb the sand.
With the fuel rods continuing to deteriorate, and with the threat of additional contaminated water leaking into the ground so close to the Columbia River, removing the water and materials contained in the K-Basins began in 1994. By 2004, crews had completed the removal of 2,100 metric tons of irradiated fuel rods from the basins and had safely moved the material into Hanford’s Canister Storage Building. The fuel rods will remain in the Canister Storage Building until such time as a permanent, national repository for spent fuel and vitrified nuclear waste is built.
The removal of the fuel rods allowed crews to begin the tedious and tricky process of vacuuming the out sludge, sediment and debris that had accumulated on the floors of the basins. The crews started with KE Basin and transferred the sludge to K West Basin so all the sludge could be stored there until ready for treatment. Ultimately, some 47 cubic yards of radioactive sludge was successfully containerized for safe storage in the K West Basin by the end of 2007.
With the removal of the sludge from the K-East Basin, Hanford workers were able to drain its water and transport the liquid to a facility for treatment and start demolition of the structure. Demolition of the above-grade portion of the K E basin was completed in September of 2009. Crews at the K-East Basin have completed demolition of the subgrade structure of the K-East Basin and removal of the discharge chute (where processed fuel was sent from the reactor to the basin pool). The reactor will now be placed into Interim Safe Storage (ISS).
In addition to work on the K Basins themselves, demolition of ancillary facilities and remediation of waste sites associated with the K Basins is currently underway. Demolition of the 183.KW and 183.KE sedimentation basins , which were used to store water need to run the KW and KE reactors respectively, have been completed. (Photo below shows the 183KE sedimentation basin work). Many ancillary facilities and waste sites near the 105KE reactor have been demolished or remediated as well. (First photo shows this work).