Science and Technology Division
NUCLEAR FUEL WASTE DISPOSAL CONCEPT
TO CANADA'S PROGRAM
Environmental and Aboriginal Groups
IN OTHER COUNTRIES
The disposal of radioactive
waste is one of the most challenging environmental problems facing Canada
today. Since the Second World War, when Canadian scientists first started
to investigate nuclear reactions, there has been a steady accumulation
of such waste. Research reactors built in the early postwar years produced
small amounts of radioactive material but the volume grew steadily as
the nuclear power reactors constructed during the 1960s and 1970s began
to spawn used fuel bundles. Although this radioactive refuse has been
safely stored for the short term, no permanent disposal system has yet
been fully developed and implemented.
Canada is not alone in this
regard. A large number of countries use nuclear power reactors but none
has yet put in place a method for the long-term disposal of the radioactive
waste. Scientists and engineers throughout the world are investigating
different possibilities; however, enormous difficulties remain.
In Canada, used fuel bundles
from nuclear reactors are defined as high-level waste; all other waste
created at different stages in the nuclear fuel cycle is classified as
low-level. Although disposal of low-level waste is an important issue,
it is a more tractable problem than the disposal of high-level waste,
on which this paper will concentrate. The paper discusses the nuclear
fuel waste management program in Canada, where a long-term disposal plan
has been under development by scientists and engineers over the past 15
years, but will not be completed for some time. Also discussed are responses
to the program by parliamentary committees and aboriginal and environmental
groups, and the work in the area being conducted in other countries.
A brief description of radioactivity,
the fission process and how a nuclear reactor works will be helpful to
All matter is composed of
atoms. Each atom consists of a nucleus, containing virtually all the mass
and made up of neutrons and protons, which is surrounded by orbiting electrons.
There are the same number of protons (positively charged) as electrons
(negatively charged) so that the atom is electrically neutral.
Most atoms are stable; those
that are not stable constantly emit energy in order to become so. This
energy is radiation and takes the form of alpha, beta or gamma rays. Alpha
particles cannot penetrate far and can be stopped by a piece of paper
or a few millimetres of air. Beta particles can be halted by several centimetres
of wood. Gamma particles, however, are highly penetrating and can be stopped
only by a certain thickness of specific material, such as concrete or
An element is defined by
the number of protons in its nucleus. Every isotope of an element has
the same number of protons but a different number of neutrons, and therefore
a different mass. Many isotopes are unstable and, by emitting radiation,
change spontaneously into different isotopes. The length of time it takes
for half of the amount of a particular isotope to transmute into another
is known as the "half life."
Uranium is a naturally occurring
radioactive element with a half life of over a billion years. It has a
number of different isotopes, some of which are susceptible to fission,
a process in which the heavy nucleus of a uranium atom absorbs a neutron
and splits into a number of smaller fragments, releasing energy in the
process. It is this energy, in the form of heat, which is harnessed in
a nuclear power reactor to produce electricity.
When a uranium atom splits,
a number of radioactive particles are found; these are usually divided
into two groups: actinides and fission products. At the same time, neutrons
are emitted that break other uranium atoms, thus continuing the heat-producing
process. Table 1 lists some of the important isotopes formed during a
nuclear reaction and which must later be disposed of as radioactive waste.
Actinide Components and Fission Products in
One Kilogram of CANDU Spent Fuel
6.1 x 10-2
2.3 x 10-1
4.0 x 10-3
8.2 x 105
1.9 x 101
1.9 x 105
3.35 x 103
9.43 x 103
* The time required
for half the atoms of a radioactive substance to disintegrate.
** Fissionable actinide.
Source: Ontario, Royal
Commission on Electric Power Planning (Arthur Porter, President), A
Race Against Time: Interim Report on Nuclear Power in Ontario, p.
As the nuclear reaction
proceeds, both the number and amount of fission products increase. After
a while, these products begin to absorb too many neutrons and the nuclear
reaction is slowed.
The CANDU, Canada's nuclear
power reactor, is fuelled by uranium oxide (UO2), which is
refined from natural uranium ore. The oxide is pressed into solid ceramic
pellets, which are then sealed inside metal zirconium tubes and welded
together to make a fuel bundle. As mentioned above, the fuel bundle can
remain in the reactor for only a limited amount of time before it starts
to slow the nuclear reaction. In a CANDU reactor, the fuel is removed
after approximately 18 months, at which point roughly 2% of the uranium
has transmuted into new elements. The used fuel bundle is intensely radioactive
and must be stored below at least three metres of water in order to block
Most of the radioactive
elements in the used fuel decay rapidly to stable elements. One hour after
removal from the reactor, the used fuel bundles have lost over 60% of
their radioactivity; however, the remaining fission products are still
highly penetrating. One year later, a person would still receive a lethal
dose of radiation from the used fuel in about ten minutes. After 500 years,
the penetrating radiation is no longer a threat but the longer-lived elements
still give off radiation that would prove dangerous if ingested. It is
for this reason that any disposal system must ensure that these fission
products do not contaminate the environment.
Water storage is the main
method for storing used fuel bundles in Canada today. It has always been
recognized that this is a safe, if temporary, means of storing radioactive
waste. Its main problem is that it requires ongoing monitoring and does
not remove the waste from the human population at large. For example,
waste from the Pickering nuclear reactor west of Toronto is stored on
site at the reactor. This is not a satisfactory long-term solution.
NUCLEAR FUEL WASTE DISPOSAL CONCEPT
In the early days, waste
from the research reactors was stored in nearby water-filled pools. Scientists
investigated other possibilities such as converting radioactive waste
into aluminosilicate glass hemispheres, which were then buried so that
the leaching and migration of buried waste could be studied. But the simplest
method, and therefore the one temporarily adopted, was water storage.
By 1975, scientists and
engineers had devised a dry storage method whereby used fuel is taken
either from the reactor or from wet storage in the pools and placed in
primary containment baskets surrounded by a secondary containment steel
liner. This is placed inside a large concrete canister that has been reinforced
with steel bars. When the canister is full, a shielding plug is welded
into place. The life expectancy of the canister is estimated to be 50
to 100 years.
Although both wet and dry
storage are acceptable methods of dealing with radioactive waste temporarily,
it has long been recognized that a permanent disposal method is essential.
In 1977, Energy, Mines and Resources Canada commissioned a study, led
by Professor F.K. Hare of the University of Toronto, to determine possible
long-term disposal methods. The task force considered a number of options,
including firing the waste into deep space or burying it in the seabed;
it eventually recommended an investigation into disposal of the nuclear
fuel waste deep in the granite rock of the Canadian Shield. This recommendation
was endorsed a year later by the Ontario Royal Commission on Electric
In 1978, the governments
of Canada and Ontario established the Canadian Nuclear Fuel Waste Management
Program. Atomic Energy of Canada Limited (AECL) was asked to assess the
concept of disposal of fuel in the Canadian Shield and to develop the
necessary associated technologies. The program, described more fully below,
is administered by AECL'S Whiteshell Nuclear Research Establishment in
Pinawa, Manitoba, and is focusing on the geological, hydro-geological,
geotechnical and geophysical aspects of disposal in the granitic rock
of the Canadian Shield. Ontario Hydro is responsible for developing interim
storage facilities and methods for transportation of the used nuclear
Early in the program problems
over siting the waste disposal facility became apparent. Many communities
approached for permission to carry out local geological studies were opposed
to such investigations. To help address these concerns, it was announced
in 1981 that the program would be modified; a waste disposal concept would
be developed first and then the site for the facility would be chosen.
Furthermore, public hearings would be held to ensure widespread participation
in the process.(3) The form
and extent of this public review will be discussed below.
In Canada, as we have seen,
the proposed method of disposal is to bury the radioactive waste deep
in the rock of the Canadian Shield. This rock formation was chosen for
a number of reasons. The Canadian Shield has been stable for at least
600 million years and most of it has not experienced major orogenic (or
"mountain-building") activity for 2.5 billion years; it is therefore
likely to remain stable for the lifetime of a disposal vault. Furthermore,
the topographic gradients within the Shield are low, which means that
the natural driving force for groundwater flow deep in the rock should
The possibility of groundwater
mobility is further diminished by the low porosity and permeability of
the large volumes of plutonic rock believed to exist in the Shield.(5)
Placing the disposal vault within this type of rock would limit groundwater
access and inhibit the movement of contaminants through the rock. Furthermore,
minerals in plutonic rock are known to interact with many of the radionuclides
in nuclear fuel waste and this plan would also decrease their mobility.
A final significant advantage
of the Canadian Shield as a storage facility is that it covers an enormous
area of land so that there would be a wide choice of sites.(6)
Given this flexibility, and because a siting decision will inevitably
bring about a great deal of controversy, AECL is developing a generic
proposal whereby its disposal facility could be located anywhere in the
Canadian Shield. Once this concept has been accepted, the difficult problem
of precise location will be addressed.
The proposed disposal vault
would resemble a mine. At a depth of between 500 and 1,000 metres, it
would occupy an area of approximately four square kilometres and consist
of 480 disposal rooms. This design would allow for the disposal of about
190,000 tonnes of used fuel.(7)
The used fuel would be sealed
inside corrosion-resistant containers made from titanium and large enough
to hold 72 CANDU fuel bundles. Inside, free space would be packed with
glass beads to provide mechanical support against external pressures in
the vault. The aim is to keep groundwater from reaching the used fuel
for at least 500 years.
Once the fuel was sealed
in containers, each would be placed in a hole drilled in the floor of
a disposal room and surrounded by buffer material. The lower portion of
the room would be backfilled by a mixture of clay and crushed granite
and topped with a mixture of bentonite and sand. Concrete bulkheads would
secure the room entrances and grouting material would be used to ensure
they were sealed. Finally, the vault would also be closed by backfilling
the access tunnels in the same way as the rooms. Even the shafts leading
to the access tunnels would be packed with crushed granite and compacted
In disposing of nuclear
fuel waste, a difficulty is to develop a system that will be secure for
thousands of years. Although it is impossible to guarantee continuing
safety, it is possible to develop models that provide a "convincing
and indirect demonstration that the proposed disposal system provides
a sufficient level of safety to both current and future generations."(9)
Since it is impossible to
test the disposal system over the time period necessary, mathematical
models have been developed to simulate how it will respond to possible
future events, in both normal and abnormal operating conditions. The models
were developed by using information obtained in defining the waste disposal
concept. To test reliability, their predictions are compared with field
and laboratory observations of certain processes (for example, the behaviour
of natural uranium deposits) and with the results of independently developed
To assess how the system
would perform after closure, the system is divided into three components:
the vault, the geosphere and the biosphere. The vault includes the waste
and its container, the buffer material surrounding the container, and
the materials used to backfill and seal the vault. A model estimates the
flow of contaminants from the vault into the surrounding geosphere, simulating
the corrosion of the containers, the release of contaminants from the
waste and their passage through the buffer and backfill.(11)
The geosphere comprises
the rock mass and its groundwater flow system. The model simulates the
movement of groundwater through the rock surrounding the vault, the transportation
of contaminants in the groundwater and the discharge of contaminants at
locations in the surface environment.(12)
Finally, the biosphere model
simulates the transport of contaminants within the biosphere through surface
water, soil, air, plants and animals. It also examines the amount of exposure
to radiation that people might experience.(13)
Though it is not possible
to predict safety with absolute certainty, the models provide a technical
basis on which to decide whether the proposed system would operate at
a safety level satisfactory for both current and future generations.
To evaluate the extent and
quality of the technical program under development by the scientists and
engineers at AECL, the company established a Technical Advisory Committee
(TAC), whose members were selected from a list of nominees submitted by
the major scientific and engineering societies in Canada.(14)
The TAC acts as an independent review which advises AECL on the research
carried out for the Nuclear Fuel Waste Management Program. This independent,
peer-review committee examines proposed research projects and suggests
alternatives and additions when necessary, looks at scientific methods,
and reviews program results to ensure that conclusions are valid. Each
year, a report is issued on the scientific and technical progress made
during the previous 12 months.(15)
At present, the TAC has
16 members, each appointed for a three-year term. It meets as a full committee
but also has four subcommittees (Geoscience, Engineered Barriers, Bioscience,
and Systems Analysis). To maintain continuity, the membership of four
sub-committees overlaps and the terms of individuals can be renewed.(16)
The Committee reports to the Vice-President, Environmental Sciences and
Waste Management, at AECL. Its autonomy is maintained by having its members
nominated by scientific societies, by having its reports open for public
consultation and by inviting public participation.
The TAC is able to provide
a necessary scientific and technical review of the Nuclear Fuel Waste
Management Program. It was recognized early on, however, that public input
is essential to ensure future acceptance of the proposed disposal concept.
It is for this reason that the public has been asked to participate a
number of times during the review process.
In October 1989, the Minister
of the Environment appointed a review panel to examine the nuclear fuel
waste management concept. Under the chairmanship of Mr. Blair Seaborn,
former Deputy Minister at Environment Canada, the panel was made up of
eight members with a wide range of technical, social and economic expertise.
A Scientific Review Group was also set up to help in evaluating scientific
and technical matters.(17)
The general manner in which
an environmental assessment and review is carried out is defined by the
Environmental and Assessment Review Process (EARP) Guidelines Order but
each panel must define the details of its particular review. In this case,
the first steps taken were to hold information gathering ("scoping")
sessions and public hearings, where groups presented their views on the
disposal concept. This was followed by an opportunity for interested parties
to review and comment on guidelines for the preparation of an Environmental
Impact Statement (EIS). The panel has held hearings in different communities
in the five provinces with a direct interest in the nuclear industry:
Saskatchewan, Manitoba, Ontario, Quebec, and New Brunswick.(18)
Throughout 1990, open houses
provided the public with information on both the disposal concept and
the ongoing review process. A total of 130 groups participated in the
scoping meetings and were thus able to comment on the Environmental Impact
Statement. As will be seen below, many groups found much to criticize
in both the disposal concept and the review process.
In March 1992, the Federal
Environmental Assessment Review Panel published the "Final Guidelines
for the Preparation of an Environmental Impact Statement on the Nuclear
Fuel Waste Management and Disposal Concept." The final Environmental
Impact Statement, expected by March 1994, will outline the nuclear waste
problem, describe the AECL disposal concept and alternatives, explain
how the concept would be implemented and discuss its likely impact.(19)
Public hearings will be
held on the Environmental Impact Statement once it has been published.
After the necessary changes and possible additions have been made, it
is hoped that the panel will be able to submit its report to the government
TO CANADA'S PROGRAM
Two House of Commons Standing
Committees have examined the Canadian Nuclear Fuel Waste Management Program
in the past decade. In January 1988, the Standing Committee on Environment
and Forestry issued a report entitled "High-Level Radioactive Waste
in Canada: The Eleventh Hour." The report's most controversial recommendation
was for a moratorium on construction of nuclear power plants in Canada
until an acceptable solution to the problem of nuclear fuel waste has
been found. Other recommendations were for: attempts to reduce both the
amount and the volume of waste produced; an independent scientific assessment
of the computer models used to test the radioactive waste concept; a public
process to determine a site; and a public review if Canada ever considers
accepting nuclear waste from other countries.(20)
In August 1988, the Standing
Committee on Energy, Mines and Resources held a much broader study of
the economics of nuclear power in Canada. Even in this context, the Committee
report's first two recommendations related to radioactive waste management.
The Committee recommended that the schedule for completion of a high-level
radioactive waste repository be advanced and that additional funds be
made available to expedite the program. Furthermore, it directed the Atomic
Energy Control Board to appear before it to present and justify the new
Environmental and Aboriginal Groups
During the scoping hearings
held by the Environmental Assessment Review Panel, a number of environmental
and aboriginal groups discussed their concerns about the proposed nuclear
fuel waste management program. Many criticized the terms of reference
under which the Panel was operating because they explicitly excluded a
number of topics, including the long-range plans for nuclear energy within
Canada. It was argued that the question of waste disposal cannot be separated
from this larger question.(22)
The lack of time and money
afforded to the public interest groups was another serious complaint.
While AECL, a federal Crown company, had a large budget to draw from,
intervenors felt they had insufficient money and time to prepare their
briefs. As one participant noted, the lasting impression is that "public
participation has been little more than a pro forma exercise."(23)
Another criticism concerned
the possible conflict of interest in having ECL perform the research on
the disposal concept. One intervenor argued that it "seems inappropriate
to trust AECL with this job of developing the waste disposal plan, when
the whole future of the nuclear industry may depend on the outcome of
Another participant claimed that the scientists and engineers working
within the "corporate culture" of AECL, would be unlikely to
challenge aspects of the disposal concept, for fear it would hurt their
Aboriginal groups from Northern
Ontario appearing before the panel were concerned that the waste disposal
facility might be placed on their lands,(26)
and that the transportation of nuclear waste through Northern Ontario
might result in an accident that would contaminate the natural environment.
It remains to be seen how
the groups appearing before the Environmental Assessment Review Panel
will respond to the Environmental Impact Statement currently being prepared
by AECL. Those who do not believe that the disposal facility should be
constructed at all, or who dislike AECL's involvement in the process,
will likely remain dissatisfied. AECL, however, has at least made an attempt
to open up the environmental review process to many who want to be heard.
IN OTHER COUNTRIES
Canada is not alone in facing
the enormous problem of radioactive waste disposal. All countries with
nuclear power reactors, nuclear weapons, or research programs will eventually
have to decide what to do with their waste. Though other governments are
also developing disposal programs, none yet has a facility in place and
public opposition is common. The United States, for example, which has
nuclear waste both from its civilian reactor program and its military
program, is a long way from finding a suitable disposal method,(27)
though it has conducted investigations into possible kinds of waste disposal
for over 30 years. In 1982, the Nuclear Waste Policy Act was passed,
which set general guidelines, policy and timetables for the disposal of
spent fuel and high-level waste. Deadlines have proved difficult to meet,
however, especially as there is growing controversy over the siting of
the waste disposal facility. The proposed siting at the Yucca Mountains
in Nevada has met with vigorous opposition and the scientific and technical
difficulties of building the proposed facility are still under investigation.
France, second only to the
United States in its production of electricity using nuclear power, is
also struggling to a find a means of disposing of its waste. The type
of repository to be built depends upon the site, which has yet to be chosen.
An announcement in 1987 of four potential sites led to numerous protests.
Since then the number of possible locations has been reduced to two, whose
whereabouts remain unknown. A final decision has been delayed for 15 years.(28)
Other European countries
are at various stages in the development of a nuclear fuel waste disposal
concept but no program is yet operating. Here too, much of the controversy
surrounds the location of the disposal vault. Canada has avoided this
question for the moment, but it is only a matter of time before it must
Although western nations
are facing enormous scientific and political problems as they try to resolve
this dilemma, their difficulties shrink when compared to those faced by
countries of the former Soviet Union and Eastern Europe, where stories
of poorly constructed reactors, inadequate safety provisions and widespread
nuclear contamination over the past four decades are too numerous to cite.
To help solve the problem of nuclear waste disposal in these countries,
it is clear that the west will have to provide both financial and technical
As we approach the next
century, Canada, like other countries with nuclear programs, continues
to search for answers to a problem that has been growing for nearly half
a century. Although methods of disposal have been devised, scientists
cannot be certain that these will continue to function for tens of thousands
This lack of certainty about
the long-term safety of nuclear waste disposal methods has led some critics
to suggest that the high-level waste should remain in storage until scientists
have developed better ways of dealing with it effectively. Nevertheless,
most countries, Canada included, have decided to proceed with present
plans for disposal systems. Canada's proposed method of deep geological
burial is the result of many years of scientific and technological research,
which is still ongoing. The final form of the disposal system, its site
and its possible date for completion are yet to be decided.
In Canada, as in other countries,
public consultation on the proposed disposal system has allowed various
groups to voice their criticisms of the project. It is hoped that extensive
consultation will make public acceptance of the system easier to achieve.
So far, Canada has managed to avoid much of the adverse reaction experienced
in other countries by not naming a specific disposal site. It is likely
that when this is done there will be considerable discussion and dissension.
Despite these future difficulties, the Canadian research program continues
to work towards a safe and environmentally acceptable way to dispose of
high-level nuclear fuel waste.
Robert L. Greyell, "Nuclear Fuel Waste Disposal: Canada's Environmental
Review Begins," p. 307.
B. Gray and G. Underdown, "Perspectives of the Proponent and Initiating
Department on the Federal Environmental Review of the Canadian Nuclear
Fuel Waste Management Program," Atomic Energy of Canada Limited,
Whiteshell Nuclear Research Establishment, Manitoba, n.d. p. 2.
Ibid., p. 3.
K. Nuttall and D.F. Torgerson, "Developments in the Canadian Concept
for Disposing of Nuclear Fuel Waste," presented at the 1991 Joint
International Waste Management Conference, 21-24 October 1991, p. 1.
Plutonic rock is rock formed as igneous rock by solidification below the
surface of the earth.
Nuttall and Torgerson (1991), p. 1.
Ibid., p. 2.
Organisation for Economic Co-operation and Development, Disposal of
Radioactive Waste: Can Long-term Safety be Evaluated?, Paris, 1991,
K.W. Dormuth and P.A. Gillespie, "Nuclear Fuel Waste Disposal in
Canada -- The Generic Research Program," AECL-10183, May 1990, p.
Ibid., p. 21.
Ibid., p. 22.
Ibid., p. 23.
These societies are: Chemical Institute of Canada, Engineering Institute
of Canada, Canadian Geoscience Council, Canadian Institute of Mining and
Metallurgy, Canadian Association of Physicists, Canadian Federation of
Biological Societies, Biological Council of Canada, Canadian Information
For copies of these reports, Annual Reports TAC-1 through TAC-12, Technical
Advisory Committee on the Nuclear Fuel Waste Management Program, contact
Professor L.W. Shemilt, Technical Advisory Committee Chairman, 1980-91,
McMaster University, Hamilton, Ontario, L8S 4K1.
Technical Advisory Committee on the Nuclear Fuel Waste Management Program,
Twelfth Annual Report, March 1992, p. 4.
Gray and Underdown, p. 4.
Federal Environmental Assessment Review Panel, "Final Guidelines
for the Preparation of an Environmental Impact Statement on the Nuclear
Fuel Waste Management and Disposal Concept," March 1992.
House of Commons Standing Committee on Environment and Forestry, "High-Level
Radioactive Waste: The Eleventh Hour," January 1988, p. 35-37.
House of Commons Standing Committee on Energy, Mines and Resources, "Nuclear
Energy: Unmasking the Mystery," August 1988, p. 7.
Submission by the Nuclear Awareness Project to the Environmental Assessment
Review Panel, 23 October 1990 (available from the Federal Environmental
Assessment Review Office).
Environment North, Submission to the Environmental Assessment Review Panel,
29 October 1990.
Nuclear Awareness Project, Submission to the Environmental Assessment
Review Panel, 23 October 1990.
Energy Probe, Submission to the Environmental Assessment Review Panel,
22 October 1990.
See, for example, Nishnawbe-Aski Nation, Submission to the Environmental
Assessment Review Panel, 22 November 1990.
Acres International Limited, A Review of Various Approaches Being Undertaken
by Industrialized Nations for the Management and Disposal of High-level
Nuclear Waste, April 1989, section 8, p. 1-14; Nicholas Lenssen,
Nuclear Waste: The Problem That Won't Go Away, December 1991, p. 34-37.
Lenssen (1991), p. 37-38.