Did You Know?
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There are about 1 million shipments of nuclear material a year in Canada. For more information, see: For a lesson about this topic, see: |
Managing Canada's Used Nuclear Fuel:
A Responsible Path Forward
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What Is It?
Almost all activities, from making dinner to driving cars, produce “waste”, an unusable or undesirable leftover material. The term “nuclear waste” tends to be applied to all radioactive material that is discarded from any nuclear activity.
This can include a variety of items, from slightly contaminated clothing, instruments and equipment, to the highly radioactive spent fuel from nuclear reactors. The common factor is radioactivity.
Radioactive waste is generally divided into three categories: low-level; intermediate-level; or high-level, depending on the level of radioactivity.
Low-level waste includes slightly contaminated clothing and items that could come from various activities, such as hospital nuclear medicine departments, research laboratories, or nuclear power plants. Most nuclear waste falls in this category.
Intermediate-level waste typically includes items such as ion exchange columns from the cooling system of a nuclear power plant, which contain a higher level of radioactivity.
High-level waste (used nuclear fuel)contains a large amount of radioactive material. The term is often used to describe spent fuel from a nuclear reactor. This is somewhat of a misnomer since the spent fuel contains considerable potential energy. Some countries, such as France, recognize this potential by reprocessing part of the fuel from its nuclear power plants to be used again.
How is Nuclear Waste Managed?
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Worker handling low-level waste from a nuclear power plant. |
Low-level waste, such as that from hospital nuclear medicine departments, contains only small amounts of radioactive materials with short half-lives. This means the radioactivity decays away in hours or days. In some cases, after holding it until the radioactivity has decayed, the waste can be treated like ordinary hospital garbage and in other cases, it may need to be incinerated.
Some low-level waste from activities other than nuclear power plants, which is contaminated with long-lived radioisotopes above a very low amount, is shipped to special disposal sites, such as that operated by Atomic Energy of Canada Limited (AECL) at its Chalk River Laboratories. Typical disposal facilities for this type of waste involve lined concrete bunkers.
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Image of the proposed low and intermediate waste facility near Kincardine, Ontario |
Low- and intermediate-level wastefrom the nuclear power plants in New Brunswick and Quebec is stored on-site in special containers made of concrete and other materials. In Ontario, all low- and intermediate-level waste from its nuclear power plants is shipped to a dedicated storage facility located adjacent to the Bruce nuclear generating stations near Kincardine, Ontario. Ontario Power Generation (OPG) is proposing to build an underground permanent storage facility at this site for these wastes.
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A worker at the Pickering Nuclear Generating Station looks over the used fuel bundles in the water-filled bay. The fuel bundles will remain in the water for about 10 years. |
High-level waste such as spent nuclear fuel from nuclear power plants is initially stored in large water-filled pools. The water provides shielding from the radiation and cooling to remove the heat generated by the radioactive material in the spent fuel. Immediately after removal from the reactor, the fuel bundle continues to generate about 6% of the heat it did in the reactor – this power level decays to about 2% after a few hours. After a year, it is generating less than 0.1% of the heat it generated in the reactor, or about 100 W per fuel bundle.
In terms of radioactivity, when removed from the reactor, the fuel bundle would deliver a radiation dose of about 50-60 sieverts per hour (Sv/h) at a distance of 30 centimetres without shielding. This dose would be lethal in minutes. It is important to make sure that people are shielded from this radioactivity and that it cannot escape into the environment.
A CANDU fuel assembly is approximately 0.5 metres long. Stacked like cordwood, all of Canada's used nuclear fuel could fit into six hockey rinks.
After 100 years, this level of radioactivity drops to about 0.3 Sv/h, and after 500 years to one millisievert per hour (mSv/h). Spending an hour near the fuel bundle after 500 years would provide a dose of radiation that is thousands of times smaller than what would lead to physical harm
After a few years the used fuel may be removed from the pools and placed in dry storage inside concrete canisters or structures. The fuel can safely be stored in this manner for periods exceeding 50 years.
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After being removed from the water-filled bays, the used fuel is placed in storage canisters like the ones shown here. The containers are stored on the site of the nuclear station in highly secure warehouses where they are constantly monitored. |
Long-term Management
At this time there is no urgency to build a permanent disposal facility for spent nuclear fuel in Canada because dry storage facilities can provide safe storage for many decades. The Nuclear Waste Management Organization (NWMO), established in 2002 by Canada’s nuclear electricity generators to develop with Canadians a management approach for the long-term care of Canada’s used nuclear fuel recommended to the federal government in November 2005 a plan called “Adaptive Phased Management”. This long-term strategy for managing used nuclear fuel was accepted by the government in 2007 and the plan is now being implemented.
Adaptive Phased Management features:
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Centralized containment and isolation of used nuclear fuel in a deep geological repository in a suitable rock formation with an optional shallow underground storage facility if required
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Continuous monitoring with the potential for retrieval for an extended period of time
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An open, inclusive and transparent implementation process with collaborative and phased decision making
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The search for an informed and willing community to host the central facility
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Site selection focused in provinces directly involved in the nuclear fuel cycle
The NWMO is currently working collaboratively with interested Canadians to develop a fair process to select a site for a deep geological repository. Several countries, such as Finland and Sweden, are proceeding with the development of geologic disposal facilities. The United States has identified Yucca Mountain in Nevada as the site for deep geological storage.
Adaptive Phased Management allows for adopting alternative methods of dealing with used nuclear fuel to benefit from innovations in technology or changing societal priorities. One of these alternate methods is to recycle a large portion of the fuel as new fuel (a step also called “reprocessing”), which has the potential to extract about 100 times more energy from the used fuel. This possible recycling step is, in fact, why it is more correct to refer to the nuclear fuel coming out of a conventional reactor as “used”, and not “spent”.
Is Nuclear Waste Dangerous?
The radiation from high-level radioactive waste can be dangerous. That is why it is handled remotely and stored in suitable, monitored and regulated facilities.
Some people are concerned about the long-lived radioactivity of used nuclear fuel. It is true that some of the radioactivity will continue essentially indefinitely. There is a significant decrease in radioactivity on a timescale of 500–1,000 years because of fission product decay. But decay of the used fuel radioactivity to original uranium levels takes about one million years.
The used fuel produced by Canadian power plants to generate electricity is controlled and stored in licensed and carefully managed facilities at the nuclear power plants. In Canada’s 46 years of using nuclear energy, no member of the public has been harmed as a result of a radiation leak from a nuclear power plant or waste storage facility.
Canada’s plan for long-term care of used nuclear fuel includes storage at reactor sites and long-term and retrievable geological storage. “Retrievable” is important because 99% of the energy in the used fuel is still available. It is hoped that future nuclear reactors will reuse this fuel for electricity production as it is a valuable and precious resource for powering the world. Retrievability is also important for those who are concerned about possible damage to the containment systems or to allow for the possibility of technological advances that provide better ways of dealing with the waste in the future.
Canada’s management of its used nuclear fuel is highly regulated. The nuclear industry knows exactly where all its used fuel is stored. It is not only managed and monitored domestically but internationally through the International Atomic Energy Agency.
| About 85,000 used nuclear fuel bundles are generated in Canada each year. As of December 31, 2007, the number of used nuclear fuel bundles stored at Canadian nuclear facilities was: | ||
FACILITY |
LOCATION |
STORED BUNDLES |
| Point Lepreau | New Brunswick |
116,070 |
| Gentilly-2 | Quebec |
107,237 |
| Bruce A | Ontario |
388,730 |
| Bruce B | Ontario |
464,856 |
| Pickering | Ontario |
571,406 |
| Darlington | Ontario |
322,757 |
| Douglas Point | Ontario |
22,256 |
| AECL-Gentilly 1 | Quebec |
3,213 |
| AECL-Whiteshell Laboratory | Manitoba |
360 |
| AECL-Chalk River Laboratory | Ontario |
4,853 |
| Total | 2,001,738 |
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Resources:
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Hans Tammemagi and David Jackson, Unlocking the Atom: The Canadian Book on Nuclear Technology, McMaster University Press, 2002, p. 138-146.
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The Nuclear Waste Management Organization: www.nwmo.org
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J.J. Whitlock, “The Canadian Nuclear FAQ”: www.nuclearfaq.ca