Part 1
The Hanford Nuclear Site is one of the most complex and arduous cleanup efforts in the history of the United States. Hundreds of billions of gallons of radioactive and chemical waste were dumped into the ground on site. Pacific Northwest National Laboratory (PNNL) issued a report in September 2021, Adaptive Site Management Strategies for the Hanford Central Plateau Groundwater, that outlines an innovative strategy to tackle the challenge of groundwater cleanup. The report suggests adopting a new approach—Adaptive Site Management—to address groundwater cleanup in Hanford's Central Plateau.
Map showing the Hanford Site, including the River Corridor and Central Plateau, Photo Credit: Adaptive Site Management Strategies for the Hanford Central Plateau Groundwater
Adaptive Site Management is centered on thorough site planning and a robust understanding of site conditions and uncertainties. Large and complex hazardous waste sites often implement this approach. Adaptive Site Management would create a groundwater cleanup framework of planning, implementation, and assessment to nimbly adapt to new information and changing site conditions at Hanford. The goal would be to develop effective cleanup strategies that achieve the required outcomes while staying on schedule and budget.
The Adaptive Site Management approach attempts to reduce uncertainty by comprehensively characterizing the contaminants in the soil and groundwater. Characterization identifies the physical and chemical properties of the waste and the extent of contaminants in the vadose zone and groundwater. Characterization also identifies the geological makeup of the site, which can influence the movement of contaminants. The characterization process gathers information that then informs waste treatment and cleanup strategies.
An Adaptive Site Management approach for Hanford's Central Plateau would include:
Establishing site objectives or end goals that are consistent with the overall Hanford Site goals and that support the development of a long-term management approach;
Developing interim objectives that provide step-by-step progress toward the overall site cleanup strategy; and
Identifying key cleanup actions to reduce uncertainty, address site complexities, and analyze data gaps.
The report proposes various long-term site and interim objectives for the Central Plateau to provide examples for implementing the Adaptive Site Management approach at Hanford. These objectives are based on the primary goal of Hanford cleanup operations—protecting the Columbia River.
The objectives must also be consistent with the United States Department of Energy’s (USDOE) decision about future land use when cleanup finishes. For example, USDOE decided that the Central Plateau is designated exclusively for industrial use, meaning manufacturing, processing, or storing materials. The decision to have the Central Plateau remain solely for industrial use means that the cleanup strategy doesn't have to be as protective as for other areas of the Hanford Site, such as the River Corridor. USDOE can leave some contamination in place because it's assuming that the land won't be openly accessible to the public. However, that is a big assumption considering that some radionuclides remain dangerous for hundreds of thousands of years. It's impossible to know what the world will look like that far into the future, but USDOE probably won't be around to prevent future generations from staying out of the Central Plateau.
Final designation of future land uses at Hanford, Photo Credit: Adaptive Site Management Strategies for the Hanford Central Plateau Groundwater
In conclusion, the report makes the case that the Adaptive Site Management approach is an appropriate tool for a large and complex site, such as Hanford. Since many of the cleanup activities in the Central Plateau are still early in the decision process and not set in stone, the report states that now is an appropriate time to implement the Adaptive Site Management approach.
In addition to outlining the Adaptive Site Management approach, the report dives into the history of Hanford's soil and groundwater contamination, current cleanup strategies, and the various challenges to cleaning up the soil and groundwater. Read on to Part 2 to learn more about soil and groundwater contamination at Hanford.
This material is funded through a Public Participation Grant from the Washington State Department of Ecology. The content was reviewed for grant consistency, but is not necessarily endorsed by the agency.