The 324 Building, situated within a mile of the Columbia River and less than a mile from Richland city limits, served as a hub of radiological research from 1966 to 1996. However, it was in 1986 that a spill of radioactive material occurred in "B Cell," one of the building's fortified chambers designed to shield researchers from radiation hazards.
Appearing contained and unbeknownst to the facility’s operators, the spilled radioactive material seeped into the soil beneath the structure, giving rise to what is now known as the 300-296 Waste Site. Subsequent routine safety procedures, including the spraying down of B Cell, inadvertently contributed to the expansion of contamination beneath the facility, creating a concealed radiological spill site.
The actual size of the spill remained concealed until late 2009, during preparations for the building’s impending demolition. Unexpectedly high levels of contamination were detected, prompting a meticulous investigation that extended from 2011 to 2014. Advanced geoprobes played a vital role in mapping the extent of this covert contamination.
With this newfound spill characterization, crews planned to remotely excavate the area beneath the hot cell. However, this endeavor presented formidable structural challenges. Therefore, to reinforce the building’s foundations, the decision was made to install micropiles beneath the structure. During the process of installing these micropiles in 2022, crews from the Central Plateau Cleanup Company (CPCCo) unearthed a disconcerting discovery—the spilled radioactive material was considerably larger and more radioactive than previously characterized. The original plan for remote excavation had to be discarded due to the deteriorating state of the building, its aging equipment and the limitations of the remote excavator arms.
In partnership with the U.S. Environmental Protection Agency (EPA), the Department of Energy (DOE), and the Central Plateau Cleanup Company (CPCCo), a comprehensive revised approach was drafted and entails deactivating the building, grouting B Cell, and eventually demolishing the entire structure. Following its demolition, a containment superstructure will be erected over the site’s remnants. Simultaneously, the contaminated soil beneath the building will undergo extensive remediation.
The history of Hanford’s 324 Building is one marked by scientific curiosity, unforeseen challenges, and adaptability. This cleanup project, situated so close to the Columbia River and the City of Richland, has captured our attention due to its elevated radioactivity levels. Importantly, the radioactive contamination has remained contained within the building’s footprint, significantly reducing the risk that precipitation will drive it toward groundwater below. The installation of groundwater monitoring stations offers additional reassurance as they consistently report no signs of contamination.