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Fukushima: Lessons learned from soil decontamination after nuclear accident

Following the accident at the Fukushima nuclear power plant in March 2011, the Japanese authorities carried out major decontamination works in the affected area, which covered more than 9,000 square kilometres ( 3,470 square miles). On Dec. 12, 2019, with most of this work having been completed, researchers provided an overview of the decontamination strategies used and their effectiveness in the Scientific Journal Soil.

Of primary concern after the Fukushima nuclear incident was the release of radioactive cesium in the environment because this radioisotope was emitted in large quantities during the accident,  it has a half-life of 30 years, and it constitutes the highest risk to the local population in the medium and long term.

This analysis in the journal provides new scientific lessons on decontamination strategies and techniques implemented in the municipalities affected by the radioactive fallout from the Fukushima accident. This synthesis indicates that removing the surface layer of the soil to a thickness of 5 cm, the main method used by the Japanese authorities to clean up cultivated land, has reduced cesium concentrations by about 80% in treated areas.

The removal of the uppermost part of the topsoil, which has proved effective in treating cultivated land, has cost the Japanese state about $35 billion (Cdn.).  This technique generates a significant amount of waste, which is difficult to treat, to transport and to store for several decades in the vicinity of the power plant, a step that is necessary before it is shipped to final disposal sites located outside Fukushima district by 2050. By early 2019, Fukushima’s decontamination efforts had generated about 20 million cubic metres of waste.

Decontamination activities have mainly targeted agricultural landscapes and residential areas. The review points out that the forests have not been cleaned up -because of the difficulty and very high costs that these operations would represent – as they cover 75% of the surface area located within the radioactive fallout zone.

 

Researchers Perfect Nanotechnology Tool for Studies of Nuclear Waste Storage

Researchers at the University of Guelph (U of G) recently published an article in Nature Scientific Reports in which they describe the first every use of antimatter to investigate processes connected to potential long-term storage of nuclear waste.  The team studied radiation chemistry and electronic structure of materials at scales smaller than nanometres.

The U of G team worked with collaborators at the French Alternative Energies and Atomic Energy Commission and utilized the TRIUMF particle accelerator in Vancouver.  Based on these first-ever measurements at the accelerator, the team able to to show that their system is a proven tool that will enable radiation studies of material to be used to store nuclear waste.

“This system can now be applied along with other measurements to determine and help to potentially design the best material for containers and barriers in nuclear waste management”, said the U of G professor Khashayar Ghandi, the lead author of the research paper.

Currently, used nuclear fuel bundles – still highly radioactive — are held in vaults in temporary storage.  Long-term, experts aim to use deep geological repositories to permanently entomb the material. Buried in rock formations hundreds of metres underground, the fuel containers would be held in engineered and natural barriers such as clays to shield people and the environment from radiation. It takes almost 100,000 years for radioactivity from nuclear waste to return to the level of natural uranium in the ground.

The researchers also discovered the intriguing properties of clays that may make them useful in other industries. Clays may serve as catalysts to change chemicals from one form to another – a benefit for petrochemical companies making various products from oil. Other industries might use clays to capture global-warming gases such as carbon dioxide and use those gases to make new products.

The research may ultimately help in designing safer underground vaults for permanent storage of radioactive waste.  Other applications of the nanotechnology tool include new ways of generating and storing hydrogen, and technologies for capturing and reusing greenhouse gases.

Cost of Nuclear Waste Clean-up in the U.S. estimated at $377 Billion

A new report by the United States General Accounting Office (GAO) estimates the total cleanup cost for the radioactive contamination incurred by developing and producing nuclear weapons in the United States at a staggering $377 billion (USD), a number that jumped by more than $100 billion in just one year.

The United States Department of Energy (DoE) Office of Environmental Management (EM) is responsible for cleaning up radioactive and hazardous waste left over from nuclear weapons production and energy research at DoE facilities. The $377 billion estimate largely reflects estimates of future costs to clean up legacy radioactive tank waste and contaminated facilities and soil. 

The U.S. GAO found that EM’s liability will likely continue to grow, in part because the costs of some future work are not yet included in the estimated liability. For example, EM’s liability does not include more than $2.3 billion in costs associated with 45 contaminated facilities that will likely be transferred to EM from other DOE programs in the future.

In 1967 at the height of the U.S.–Soviet nuclear arms race, the U.S. nuclear stockpile totaled 31,255 weapons of all types. Today, that number stands at just 6,550. Although the U.S. has deactivated and destroyed 25,000 nuclear weapons, their legacy is still very much alive.

Nuclear weapons were developed and produced at more than one hundred sites during the Cold War. Cleanup began in 1989, and EM has completed cleanup at 91 of 107 nuclear sites, Still, according to the GAO, “but 16 remain, some of which are the most challenging to address.” 

EM relies primarily on individual sites to locally negotiate cleanup activities and establish priorities. GAO’s analysis of DOE documents identified instances of decisions involving billions of dollars where such an approach did not always balance overall risks and costs. For example, two EM sites had plans to treat similar radioactive tank waste differently, and the costs at one site—Hanford—may be tens of billions more than those at the other site. 

Each of the 16 cleanup sites sets its own priorities, which makes it hard to ensure that the greatest health and environmental risks are addressed first.
This is not consistent with recommendations by GAO and others over the last two decades that EM develop national priorities to balance risks and costs across and within its sites. 

By far the most expensive site to clean up is the Hanford site, which manufactured nuclear material for use in nuclear weapons during the Cold War. In 2017, the DoE estimated site cleanup costs at $141 billion.

Environmental liabilities are high risk because they have been growing for the past 20 years and will likely keep increasing.

EM has not developed a program-wide strategy that determines priority sites. Instead, it continues to prioritize and fund cleanup activities by individual site. Without a strategy that sets national priorities, EM lacks assurance that it is making the most cost-effective cleanup decisions across its sites.

The GAO is made three recommendations to DOE: (1) develop a program-wide strategy that outlines how it will balance risks and costs across sites; (2) submit its mandated annual cleanup report that meets all requirements; and (3) disclose the funding needed to meet all scheduled milestones called for in compliance agreements, either in required annual reports or other supplemental budget materials.

Clean-up of Radioactive Material in Port Hope Finally Underway

After decades of study and planning, the clean-up or radioactive contamination in the community of Port Hope, Ontario is finally underway.  The Town of Port Hope, located approximately 100 km (60 miles) east on Toronto on Lake Ontario, has an estimated 1.2 million cubic metres (1.5 million cubic yards) of historic low-level radioactive waste scattered at various sites throughout the town.

The contaminated soil and material will be excavated to moved to the LongTerm Waste Management Facility, which is essentially an engineered aboveground landfill where the waste will be safely contained, and the long-term monitoring and maintenance of the new waste management facility.

Other historic low-level radioactive waste – primarily soil contaminated with residue ore from the former radium and uranium refining activities of Eldorado Nuclear — and specified industrial waste from various sites in urban Port Hope will be removed and safely transported to the new facility.

The historic low-level radioactive waste and contaminated soil, located at various sites in the Municipality of
Port Hope, are a consequence of past practices involving the refining of radium and uranium by a former federal Crown Corporation, Eldorado Nuclear Limited, and its private-sector predecessors. These waste materials contain radium-226, uranium, arsenic and other contaminants resulting from the refining process.

The historic waste and surrounding environment are monitored and inspected regularly to ensure the waste does not pose a risk to health or the environment. As part of the Port Hope Area Initiative (PHAI) construction and clean-up phase, the waste will be excavated and relocated to the new Port Hope long-term waste management facility.

In an interview with CBC, Scott Parnell is the General Manager of the Port Hope Area Initiative, which is in charge of the cleanup. He says that after decades of planning, the first loads of an estimated 1.2 million cubic metres of historic low-level radioactive waste will be on the move.

Scott Parnell, general manager of the Port Hope Area Initiative, stands near the town’s harbour.

“There’s been a lot of planning a lot of studies a lot of determination into how to approach the work safely, but this will be the first time we will be removing waste from the community,” said Parnell, who has overseen similar operations in Washington state and Alaska.

The $1.28-billion cleanup operation is a recognition by the federal government that the waste is its “environmental liability.” The radioactive tailings were the byproduct of uranium and radium refining operations run by Eldorado, a former Crown corporation, between 1933 and 1988.

Parnell says that the tailings were given away for free, which helps explain how the contamination was spread through the town.

“So, basically they offered it up and it was used for fill material to level up people’s backyards, for building foundations, for those kinds of things. So, that’s how the material got spread around the community,” Parnell said.

Parnell says an estimated 800 properties may be affected, but says there’s no indication the low levels of radiation are dangerous.

“There’s little human risk associated with the waste that’s identified here in Port Hope,” he said.

The first wastes to be remediated are currently stored under tarps at three locations including the Centre Pier, the Pine Street North Extension in the Highland Drive Landfill area and at the municipal sewage treatment plant. The Centre Pier is the first site to be remediated.

Aerial image of the first locations to be remediated. (source: Canadian Nuclear Laboratories)