The public usually has low to no risk from the Hanford nuclear reservation, even if radioactive releases occur on site, according to the initial results from a new review.
The Consortium for Risk Evaluation with Stakeholder Participation, or CRESP, has released a preliminary report as it reviews risk at Hanford.
The review has looked at just part of Hanford to date, including contaminated groundwater and underground tanks holding 56 million gallons of radioactive waste. It also has covered some potentially high-risk facilities, including the Plutonium and Uranium Extraction facility, or PUREX.
Other areas, including some of the huge chemical processing plants and some waste sites where large amounts of contaminated liquids were dumped into the ground, will be included in the next report.
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The Department of Energy commissioned the $4 million study from the independent, multi-university group CRESP to identify and characterize potential risks at Hanford. The review is intended to provide information to help guide decisions about the order that remaining cleanup work should be done, according to CRESP.
David Kosson, the review’s principal investigator, said that much cleanup work has been done at Hanford, but remaining cleanup is expected to take more than 50 years and cost more than $100 billion.
“It’s important to take a step back periodically to assess what is remaining and how to think about the challenges ahead,” he said.
Parts of the 586-square-mile nuclear reservation were left heavily contaminated with radioactive and hazardous chemical waste by plutonium production from World War II through the Cold War for the nation’s nuclear weapons program.
The preliminary report by CRESP grouped cleanup activities by potential risk, including those considered the highest priority based on potential risks to human health and environment.
High priorities include reduction or elimination of risks associated with earthquakes, fires, extended loss of power or other external events, the preliminary report said.
Much of the risk now to human health would be to workers or others near central Hanford facilities, rather than to the public at the site’s boundaries and in areas where the public can freely travel, including the Columbia River, it said.
An earthquake at PUREX in central Hanford could collapse the building and its tunnels, which were used to dispose of contaminated materials. People within 100 yards of PUREX could be exposed to radiation, the preliminary report said.
One tunnel was built almost entirely of railroad ties in 1956. The second tunnel was built of stronger material, but contains 28 rail cars of waste.
Most cleanup has yet to be done at PUREX, which operated from the ’50s until 1990 to chemically separate plutonium, uranium and neptunium from irradiated fuel. Almost 70 percent of Hanford’s irradiated fuel was reprocessed there.
A large fire is a worry for the Central Waste Complex, potentially exposing people within 100 yards to radiation, the preliminary report said.
The risk could increase as the complex continues to receive radioactive waste for storage, even though the Hanford budget does not allow it to be repackaged, and waste contaminated with plutonium cannot be shipped to the Waste Isolation Pilot Plant in New Mexico for disposal. The national repository is closed after a fire and spread of radiation in 2014.
The Waste Encapsulation and Storage Facility, where cesium and strontium are stored in capsules under water, is at risk in an accident that results in the loss of water needed to provide cooling and radiation shielding, the preliminary report said.
Hanford’s underground tanks pose a threat through generation of flammable hydrogen, with a fire or explosion spreading contamination in the air or ground, the interim report said. The report took a tank-by-tank look at risk, including which of Hanford’s 177 tanks pose the greatest risk to groundwater.
It also mentioned chemical vapors from tank waste as a risk to workers.
In some cases, the cleanup work poses a potential risk to people, the interim report said.
The highly radioactive spill under Building 324 just north of Richland could possibly be left for a time to allow radiation to decay to lower levels, the interim report said. Contamination does not appear to be spreading, although aging water pipes nearby could break and spread contamination.
Cleanup of the high-risk 618-11 Burial Ground by the Columbia Generating Station, a commercial nuclear power plant, could jeopardize the plant’s operation or worker safety in the event of a fire or a release of radioactive material, the preliminary report said. Delaying cleanup until the plant closes is worth consideration, it said.
The study was criticized earlier by the Hanford Advisory Board, which feared when it was launched that it could be used by DOE to reduce cleanup commitments.
Kosson emphasized during a recent presentation that the review’s information is not intended to preempt any requirements imposed by federal or state law, treaties or the Tri-Party Agreement.
“There is nowhere in the document where it says do not clean up or clean up less,” he said.
It provides relative ratings of risk to people and the environment, but does not rank risks, he said. Many other factors will be used to decide cleanup priorities, including legal obligations, community values, the availability of resources such as national repositories for radioactive waste, the availability of trained workforce and retaining knowledgeable workers.
“Hopefully this will help provide the basis for understanding why Hanford is so complex ... and why it requires extensive resources to carry out the cleanup mission,” he said.
The report should not be confused with a report to Congress released recently that analyzed how effectively DOE addresses risk at all its cleanup sites, Kosson said. That report was criticized by Washington and Oregon state officials, who accused its authors of focusing instead on ways to reduce costs at the expense of robust environmental cleanup.
CRESP was asked to organize the committee that prepared that report, but did not write it.
The preliminary Hanford report and a link for submitting comments is posted at www.cresp.org/hanford.