The last of the nine nuclear fuel pools at the Hanford Site was stabilized early last week.

As part of the Manhattan Project during World War II, the U.S. government built the world’s first full-scale nuclear production reactor – the B reactor – in Richland in 1944.

Energy Department spokeswoman Cerise Peck said the main purpose of the work is to prevent contaminated water from entering the Columbia River.

“The K-Basin was a key project in our risk reduction mission and filling it with mortar and removing the water was a big step forward for us,” Peck said.

The overall Hanford mission for the Department of Energy is to treat tank waste and remediate the environment.

The site for the plutonium production plant was originally chosen because of its proximity to the Columbia River and the area’s low population density, said Rebecca Burghart, Hanford site manager for the National Park Service. However, many farmers and Native Americans were relocated for the project. In the years that followed, eight more reactors were built across the 580-square-mile site.

For about 30 years, the site produced plutonium for use in nuclear weapons. Some of it was used in the “Fat Man” bomb dropped on Nagasaki, Japan, in 1945. Plutonium production at the site continued when the United States entered the nuclear arms race with the Soviet Union. Separating the plutonium from the uranium generated enormous amounts of waste, Burghart said.

“You can imagine it like this: From a pile of uranium the size of an elephant, you would get plutonium the size of a kitten,” said Burghart. “This chemical separation process creates a lot of waste.”

Now, more than 30 years after plutonium production ended at the site, the last spent fuel pool has been stabilized by the Central Plateau Cleanup Company under contract with the U.S. Department of Energy. The stabilization included draining nearly 1 million gallons of contaminated water from the pool and then covering the remaining contaminated debris with mortar to mitigate the damaging effects, according to the Energy Department.

The Hanford cleanup has long been a contentious issue. Seattle state Democratic Rep. Gerry Pollet, founder of the organization Heart of America Northwest, said the stabilization of the K Basin was “great,” but it came too late.

“For 25 years, this has been considered a top priority. To remove the garbage from the basin to end the risk of disaster and protect the Columbia River,” Pollet said. “This should have happened 20 years ago.”

Heart of America Northwest is the region’s oldest and largest Hanford cleanup advocacy group, with 6,000 members, Pollet said. Twenty years ago, Pollet said, the group had 15,000 annual members because of concerns that Hanford would become a national radioactive waste disposal site. A lack of awareness today about the circumstances of the Hanford site is a major problem in holding cleanup agencies accountable, he said.

“I teach environmental assessment at Western Washington University and environmental health at the UW School of Public Health. My students – 20 years ago, every student from Washington state who enrolled at the university knew what Hanford was. And today, three out of 20 students know what it is,” Pollet said. “It’s a huge problem.”

Stabilizing the K Basin is not the end of the story when it comes to Hanford cleanup.

Peck spoke about dozens of ongoing remediation projects underway by the Department of Energy, while Pollet lamented that insufficient attention was being paid to the numerous leaks in the underground tanks on the site.

“This is a very big step forward,” Pollet said. “It just took decades.”