Why is there so much plutonium at Chalk River?

October 25, 2020

A consortium of private multinational corporations is proposing to create a giant mound of radioactive wastes at Chalk River, Ontario, less than a kilometer from the Ottawa River.  According to the draft Environmental Impact Statement (EIS) the proposed mega-dump will house a rather large quantity of plutonium.

What is plutonium and why should we worry about it?

Plutonium is a human-made radioactive element that is created as a byproduct in nuclear reactors. The first reactors were built to produce plutonium for use as a nuclear explosive in atomic weapons. Plutonium can also be fabricated into fuel elements for nuclear reactors.

Plutonium remains radioactive for tens of thousands of years after it is created.  It comes in several different varieties or “isotopes”.  The most abundant varieties are plutonium-239, with a half-life of 24,000 years; and plutonium-240, with a half-life of 6,600 years.  The half-life is the time required for half of the atoms to undergo radioactive disintegration. When a plutonium atom disintegrates it is transformed into another radioactive material, sometimes one with a much longer half-life.

All isotopes of plutonium are highly toxic. Even very small doses can lead to radiation-induced illnesses such as cancer, often resulting in death.

Why is there plutonium at Chalk River?

The decision to build the Chalk River Laboratories (CRL) was taken in Washington, D.C. in 1944.  Canada, Great Britain and the United States agreed to build the facility as part of an effort to produce plutonium for bombs.  In fact, plutonium produced at CRL played a role in both the US and UK nuclear weapons programs.

During the late 1940s, British scientists carried out all necessary pilot plant work at Chalk River to design their own large plutonium production plant at Windscale, England.  Plutonium produced at CRL arrived in England just months before the first British nuclear explosion took place in Australia in 1952.

For three decades, plutonium produced in Canadian research reactors was sold to the U.S. military to help finance the Chalk River Laboratories.  A reprocessing plant at Chalk River was built to extract plutonium from irradiated nuclear fuel dissolved in nitric acid. It was shut down in 1954, but irradiated fuel containing Canadian plutonium was shipped to the U.S. until the mid-1970s.  In all, at least 250 kg of plutonium was sold to the U.S. for nuclear weapons and warheads.

Three buildings central to plutonium production are slated for demolition

Various facilities at CRL were used in the 1940s and 1950s to extract plutonium from fuels irradiated in the NRX reactor.  In 2004, environmental assessments were initiated governing the radioactive demolition of three such structures:

•       The Plutonium Tower, used in the late 1940s to extract plutonium from fuel   rods irradiated in the NRX reactor.

•       The Plutonium Recovery Laboratory, used between 1949 and 1957 to extract plutonium isotopes from enriched fuels irradiated in the NRX reactor.

•       The Waste Water Evaporator, used between 1952 and 1958 to process radioactive liquid wastes left behind from the plutonium extraction work. Decommissioning of this facility would include: removal, treatment and storage of plutonium-bearing liquid wastes and sludge in tanks, plutonium-contaminated process lines and equipment; decontamination and removal of process equipment and processing cells for handling plutonium; removal of building structures containing plutonium residues; segregation of solid wastes and transfer of these plutonium-contaminated materials to waste management facilities at CRL.

In December 2011 the Canadian Nuclear Safety Commission gave the go-ahead for dismantling the first of these structures, the Plutonium Tower.  In 2012, changes to the Canadian Environmental Assessment Act introduced by Stephen Harper’s government made it permissible to demolish radioactively contaminated buildings without any environmental assessment (EA).

To date, only the auxiliary buildings associated with the Plutonium Tower have been decommissioned, but the Tower itself is still standing.  And as far as the Plutonium Recovery Lab and Waste Water Evaporator go, neither has been decommissioned. All these decommissioning projects will be difficult, and will generate lots of long-lived, intermediate-level waste.

These buildings are just three examples of demolition projects that would produce plutonium-contaminated rubble likely destined for the proposed megadump. Chalk River scientists were keenly interested in testing plutonium as a reactor fuel.  Some three tonnes of plutonium-based fuel elements were fabricated at Chalk River using remote handling devices called gloveboxes. Such facilities would also result in plutonium-contaminated wastes when demolished.

The draft EIS estimates that total quantities of plutonium to be placed in the planned landfill-type facility would be measured in the trillions of Becquerels. A Becquerel is a unit of radioactivity, indicating that one radioactive disintegration is taking place every second. (Every radioactive atom eventually disintegrates, or explodes, giving off one or two subatomic projectiles called “atomic radiation”. All forms of atomic radiation — alpha particles, beta particles, gamma rays, and neutrons–are damaging to living cells.)

Plutonium will inevitably leak into the Ottawa River (EIS)

The draft EIS indicates that after failure of the landfill cover, which is bound to occur at some point after abandonment, millions of Becquerels of each plutonium isotope would enter Perch Creek every year.  Perch Creek flows into the Ottawa River about 1 km away.

Canadian Coalition for Nuclear Responsibility and Concerned Citizens of Renfrew County and Area

May 2017

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