Historic Hanford Contamination is Worse Than Expected: Oregon Experts Weigh In
324 Building (Photo U.S. Department of Energy)
In late June, the U.S. Department of Energy reported that radioactive contamination beneath a building at the Hanford Nuclear Site is worse than originally thought.
The Hanford 324 Building is located on the south end of Hanford – in what’s known as the 300 Area – just 1,000 feet from the Columbia River. The US DOE has known about one spill under the building for over a decade, and has been working on a plan for cleanup of the area while also making progress in other areas of Hanford since production turned to cleanup at the site in the 1980s.
The agency knew the contamination in the soil was serious, but sampling this spring found unexpected contamination deeper in the soil and outside the previously known spill area. So what does that mean? Oregon Department of Energy Assistant Director for Nuclear Safety and Emergency Preparedness Maxwell Woods and Hanford Hydrogeologist Tom Sicilia weigh in.
Q: The spill is beneath the 324 Building. What was that building used for at Hanford?
A: It was a research building during Hanford’s production years, testing spent nuclear fuel and radioactive waste stabilization dating back to the 1960s. It even treated some waste from the Three-Mile Island accident.
Q: What happened when US DOE discovered the spill?
A: The original plan to demolish the building was changed when DOE first identified contamination under the building in 2010 – both cesium and strontium are in the soil at levels high enough that direct contact from a human would not be survivable.
At that time, while US DOE worked on a plan to clean up the contamination, it decided (and the U.S. Environmental Protection Agency agreed) the best course of action in the interim was to temporarily leave the building standing, as it acts as a shield from radiation exposure and keeps rainwater away from the contaminated soil so it doesn’t spread.
Q: So what changed?
A: Over the past decade, US DOE started some very complex remediation work using remotely operated equipment to cut the floor of the building, dig into the soil, and try to contain the really radioactive soils. As they did work to support the dig, they found more, previously unknown contamination outside the robot’s reach that made it clear the problem was larger than expected.
US DOE stopped work to reassess the approach. This is a good example of how challenging the Hanford cleanup is – there’s always a risk that new or worse contamination than expected will be found as cleanup progresses.
Q: Is the groundwater or the Columbia River at risk of exposure to the contaminated soil?
A: Based on data from monitoring wells, the US DOE reports that the spill has not migrated to groundwater, so at this time the groundwater that flows to the river poses a minimal risk. But it will be important moving forward that the area remain covered and protected and for monitoring to continue while a cleanup plan is identified.
We hear US DOE may also be considering adding additional groundwater monitoring in the area to capture more data, which we support.
Hanford’s cocooned N Reactor can be seen from the Columbia River.
Q: What’s the plan now?
A: Since it’s important to keep the area shielded for exposure and as protected as possible from infiltrating rainwater, US DOE is considering a number of options, one being building a large metal tent-like shell over the area, and then knocking down the building (which would then be under the shell) before continuing to dig everything out. This will prevent airborne radioactive dust and allow the work to continue under a larger protected area in case more contamination is found.
Once excavated, the original plan was for the contaminated soil and the 324 Building itself to be stabilized and solidified in grout, classified, and then potentially disposed at a specially designed landfill at the Hanford site (the Environmental Restoration Disposal Facility, or ERDF), which is farther away from the Columbia River. However, until the waste classification is complete, it is unclear if the disposal pathway to ERDF is legal.
This wouldn’t be the first time US DOE took this approach of covering a site to make it safe and dry and to allow for further decay. Seven of the nine former nuclear reactors on the Hanford site, for example, were “cocooned” and are now being allowed to cool for 75 years before they’ll be reevaluated for potential demolition or other actions. One reactor is left to be placed in “Interim Safe Stabilization” (the formal term for the cocooning process), bringing the total to eight. The B Reactor, which is the first full scale nuclear reactor in the world, will remain un-cocooned as part of the Manhattan Project National Historic Park.
Q: What are the risks with the new plan?
A: If US DOE decides to construct the big metal shell, a next question will be whether work should continue with robots or remotely operated equipment to resume the digging, or if the agency should wait a few more decades to allow the radioactive materials in the soil to decay further.
Depending on how “hot” the soil really is – it could be hundreds of years before it would be safe enough for humans to manually excavate it. Remotely operated equipment is used across the Hanford site for safe cleanup activities.
While the risk to groundwater and the river are low, there is a balance between the inevitable migration of contaminants over time and the ability to safely complete the cleanup. In the near-term, US DOE seems to be doing the right thing, and is “measuring twice” to avoid having to go back out and re-dig this complicated and dangerous soil. This pause will allow a more efficient and protective remedy to be developed for review by stakeholders, Tribal nations, the public, and site regulators.
Q: What will we be watching for here in Oregon as this situation progresses?
A: It will be vital to develop a plan that protects the workforce – not to mention a plan that figures out what to do with the potentially lethal dirt that they dig up.
The Oregon Department of Energy’s role is to ensure cleanup actions at Hanford consider Oregon’s perspective, primarily that cleanup decisions are protective of the Columbia River, so we will continue to monitor the situation through our work with the Hanford Site, our support to the Oregon Hanford Cleanup Board, and other groups. In particular, we will be keeping an eye on the groundwater monitoring data near the 324 Building to understand if contamination is migrating into groundwater and towards the Columbia River.
In addition to the US DOE working toward a solution, the U.S. Environmental Protection Agency is also highly engaged since it regulates this waste site. US DOE will be required to follow the Comprehensive Environmental Response, Compensation, and Liability Act (also known as CERCLA) process for any changing conditions.
More information will be presented by US DOE at the next Hanford Advisory Board meeting on August 23, 2023.
