Nuclear Waste: Spent Fuel Bundles

Candu Fuel Rods and Bundles

A fuel bundle contains many processed uranium rods. “Each bundle is about 50 cms long and weighs about 23 kgms… Several thousand of these bundles are required to initially fuel a reactor. After that, several bundles a day, per reactor, are replaced as the reactors operate at full power.”

Fuel bundle

Courtesy of Robert Del Tredici

Once a bundle is “spent” (after 12-18 months in the reactor), it is highly radioactive. The 1978 “Ontario Royal Commission on Electric Power Planning” (aka: “Porter Commission”) stated, “The extreme lethality of a freshly removed spent fuel bundle is such that a (unprotected) person standing within a metre of it would die within an hour.” For decades, authorities have unsuccessfully tried to identify and secure safe places to permanently store spent fuel. When spent fuel bundles are removed from the reactor, they are placed in water filled pools “to cool and shield them until their radioactivity declines.” After about 10 years, the fuel bundles have cooled sufficiently to be transferred robotically to “high level” dry storage facilities. These temporary storage units are said to have a “design life” of about 50 years, and perhaps longer under favourable conditions. Meanwhile, some of the material inside the containers remains radioactive for thousands and thousands of years.

Ontario Power Generation (OPG) says that as of December 1999, “the total number of used fuel bundles in storage was approximately 1.3 million.” * In 1978, the Porter Commission report predicted that, “During the next forty years (and probably for thousands of years), the management of hundreds of thousands of such bundles (in Ontario alone), which at all times must be isolated from the earth’s ecosystem, will clearly present a problem of massive proportions.”

Facts and quotes come from the Ontario Power Generation publication: “Nuclear Waste Management – Managing Ontario Power Generation’s Nuclear Waste Safely and Responsibly”, October 2000 (except where otherwise noted).

High-level Nuclear Waste Dry Storage Silos

Courtesy of Robert Del Tredici

Courtesy of Robert Del Tredici

Each tall, cylindrical, concrete silo contains a metal storage cylinder, which in turn holds spent fuel bundles. The number of bundles can range from a couple of hundred to over 600, depending on the design of the containment system. The dry storage containers in use at the Western Waste Management Facility (WWMF) will be the “Pickering” design, made for the Pickering dry storage facility at the Pickering, Ontario nuclear complex on Lake Ontario. Each container holds 384 fuel bundles. (Initially the WWMF planed to use a special “Bruce” dry storage container. A Bruce used fuel bundle has 37 rods, whereas a Pickering used fuel bundle has 28 rods, although a Bruce and Pickering bundle are designed to be the same size. In the end, the operators of the WWMF chose to use the Pickering model of container rather than their special design.)
Schematic of Pickering dry storage container

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