GLOBAL WARMING AND SUSTAINABLE ENERGY SUPPLY
WITH CANDU NUCLEAR POWER SYSTEMS
P. BOCZAR, A. DASTUR, K. DORMUTH, A. LEE, D. MENELEY
and D. PENDERGAST
Atomic Energy of Canada Limited, 2285 Speakman Drive, Mississauga, Ontario, L5K
1B2, Canada
JOHN LUXAT
Ontario Hydro, 700 University Avenue, Toronto, Ontario
(Presented to the Global Environmental & Nuclear Energy Systems Conference - 2 in Tsuruga by Duane Pendergast. Published in the Proceedings of the Second International Symposium GENES - 2, 29 October - 1 November 1996, Tsuruga, Japan, Pergamon, 1997.)
(Copyright assigned to Elsevier Publishing)
ABSTRACT
The United Nation’s Intergovernmental Panel on Climate Change (IPCC) review of global warming issues suggests man’s activities have resulted in a discernible influence on global climate. The panel identifies options which could be employed to ameliorate the climate influencing greenhouse effect which is attributed primarily to carbon dioxide and other gaseous emissions from fossil fuel energy sources. One option identified is nuclear power, as an alternative energy source which would reduce these emissions. The panel observes that, although nuclear power is a relatively greenhouse gas free energy source, there are a number of issues related to it’s use which are slowing it’s deployment. This paper enumerates the issues raised by the IPCC and addresses each in turn in the context of CANDU reactors and sustainable development. It is concluded that the issues are not fundamental barriers to expanded installation of nuclear fission energy systems. Nuclear reactors, and CANDU reactors in particular, can meet the energy needs of current generations while enhancing the technological base which will allow future generations to meet their energy needs. The essential requirements of a sustainable system are thus met.
INTRODUCTION
The United Nation’s Intergovernmental Panel on Climate Change (IPCC) concludes that human activities are increasing levels of greenhouse gases in earth’s atmosphere. Their review of evidence suggests there is now a discernible human influence on global climate. They identify options which could be employed to ameliorate these effects.
Working Group III of the IPCC focused on review of the socioeconomic aspect of impacts, adaptation and mitigation of global climate change over the short and long term. Their summary for policy makers (IPCC) includes a position on the possible role of nuclear power as an alternative energy source with reduced carbon dioxide emissions. They conclude that:
“Nuclear energy is a technology that has been deployed for several decades in many countries. However, a number of factors have slowed the expansion of nuclear power, including: (a) wary public perceptions resulting from nuclear accidents, (b) not yet fully resolved issues concerning reactor safety, proliferation of fissile material, power plant decommissioning, and long-term disposal of nuclear waste, as well as, in some instances, lower-than-anticipated levels of demand for electricity. Regulatory and siting difficulties have increased construction lead times, leading to higher capital costs for this option in some countries. If these issues, including inter alia the social, political, and environmental aspects mentioned above, can be resolved, nuclear energy has the potential to increase its present share in worldwide energy production.”
This paper begins by examining the role nuclear energy can play in providing sustainable global energy from the perspective of a potential need to significantly limit carbon dioxide releases to avoid harmful global climate change. AECL is taking necessary action to ensure the long term development of the CANDU system as a sustainable energy source while providing a viable electrical energy option to meet current needs. The ultimate goal of Canadian nuclear programs is to ensure understanding of socioeconomic, environmental and technological aspects of nuclear energy so that this energy supply option is utilized to its full capability to support sustainable global energy development.
Each of the issues identified by the IPCC as slowing the expansion of nuclear energy is reviewed. Programs are underway in Canada which will provide additional information and knowledge to resolve these issues. Foremost among these is the current public review of the Canadian concept for the disposal of nuclear fuel waste (AECL). Reactor safety has always been a top-priority issue in Canadian reactor programs; Canada’s safety record is excellent, and CANDU reactors offer unparalleled safety characteristics for large scale installation around the world. With regard to public perception, ‘time will tell’, and we can fully expect public understanding and acceptance to improve as the excellent safety record of this technology unfolds in the future. Canada also is engaged in programs related to decommissioning of nuclear plants and to provide means for preventing the uncontrolled spread of weapons-usable material. Canada continues to establish research programs to further develop the CANDU energy system and resolve technical aspects of postulated nuclear accidents.
GLOBAL CLIMATE CHANGE AND SUSTAINABLE ENERGY DEVELOPMENT
The concept of “sustainable development” has been established over the last several years. Gradual realization of mankind’s disproportionate influence on the global environment has revealed a requirement to consider human needs in the context of sustainability of the global ecosystems that support life. The World Commission on Environment and Development states (Bruntland) that:
“In essence, sustainable development is a process of change in which the exploitation of resources, the direction of investments, the orientation of technological development, and institutional change are all in harmony and enhance both current and future potential to meet human needs and aspirations”
Canada’s Parliament provides (Canada) a variation on that definition:
““Sustainable development” means development that meets the needs of the present, without compromising the ability of future generations to meet their own needs”
The IPCC is concerned with the potential for human generated carbon dioxide to endanger the ability of the global atmosphere to support life. Does the development of nuclear energy conform to these definitions of sustainability in the context of the global warming issue addressed by the IPCC? We think so. Nuclear power is capable of supplying bounteous quantities (Pendergast February, 1991) of energy. We expect that continuing comparative evaluation of the environmental impacts of alternative energy systems (IAEA) will ultimately demonstrate minimal impact to earth’s life support systems from the nuclear energy option. There is a great deal of scope for present and future development of nuclear fuel cycles to make much more efficient use of basic fission fuel sources. Current nuclear energy systems and fission fuel supplies can be developed to supply a substantially greater fraction of world energy needs continuing over the very long time period needed to establish sustainability with respect to the global warming issue. These systems can satisfy the energy needs of many generations of humans while avoiding the carbon dioxide release to the atmosphere characteristic of present energy systems. The basic requirement for sustainable energy development is thus met. Future generations will utilize different systems to extract fission energy. We have established a strong base of nuclear technology in the past fifty years. That information allows for confident predictions that many future generations will be able to utilize it for energy needs.
CANDU heavy water reactors, by virtue of their use of heavy water as a moderator, have the potential for particularly efficient conversion of fissile material into energy. Although fission fuel supplies are ample at present rates of consumption for many decades, this fuel conservation (Pendergast, October, 1991)potential of CANDU reactors will play a role in ensuring energy is available for future generations. AECL’s research facilities are developing information on variations of CANDU fuel cycles which are intended to take advantage of the CANDU reactor’s “neutron economy” to make the best possible use of fissile and fertile fuel resources.
CANDU FUEL CYCLE INNOVATION AND SUSTAINABILITY
Sustainable energy development must take into account global energy needs in the context of economic and environmental sustainability. The adaptability of the CANDU nuclear power system to use available and future fissile and fertile fuel supplies is important to it’s ability to supply increasing amounts of energy now and for many future generations. Relatively simple current CANDU technology can be adopted now where economically feasible. There is ample scope for the development of more sophisticated variations of the basic fuel cycle as economic and environmental conditions evolve with the use of energy resources by present and future generations.
The original requirement for CANDU to use natural-uranium fuel has resulted in it being the most neutron-efficient commercial reactor. This was primarily achieved through the use of heavy water for both coolant and moderator and the use of low-neutron absorbing structural materials in the fuel and core. High neutron economy in CANDU reactors provides a flexibility in fuel use that is not available in other reactors and, in particular, the ability to utilize low-grade (e.g., low fissile content) nuclear fuels. On-power refuelling is a second feature of CANDU reactors that contributes to their ability to use different fuel types. On-power refuelling provides a great deal of flexibility in accommodating new fuels. The fuel-management scheme can be chosen to shape the power distribution in the core: both axially, along each channel, and radially from channel to channel across the core. The number, type, and location of bundles added at each visit of the fuelling machine to a channel can be varied, as well as the fuelling frequency. Fuelling schemes can be modified to optimize the power distribution in terms of safe operation and fuel utilization.
AECL is currently studying (Boczar, October, 1996) several options to increase the efficiency of fuel use, including adaptation of CANDU to synergistic deployment with other reactor types.
The easiest first step in CANDU fuel-cycle evolution may be the use of slightly enriched uranium, including recovered uranium from reprocessed light water reactor spent fuel. Relatively low enrichment (up to 1.2%) will result in a two- to three-fold reduction in the quantity of CANDU spent fuel per unit energy production and greater flexibility in the design of new reactors.
A country that has both CANDU and LIGHT WATER reactors can exploit a natural synergism between these two reactor types to minimize overall waste production, and maximize energy derived from the fuel. This synergism can be exploited through several different fuel cycle processes. This makes CANDU reactors particularly relevant to LWR owners that intend to reprocess the spent light water reactor fuel as part of their fuel disposal program.
CANDU fuel can be designed to utilize chemically reprocessed plutonium from light water reactor fuel. A promising recycle option involving direct use of spent light water reactor fuel CANDU has a higher degree of proliferation resistance than does conventional chemical reprocessing. It uses a dry process for converting the spent fuel into CANDU fuel, without separating the plutonium which remains mixed with fission products. Good progress is being made by a current development program (Boczar, April, 1996) supported by Korea, Canada and the United States.
In the longer term, CANDU reactors also offer synergistic fuel cycles with fast breeder reactors. Long-term energy security would be provided by a system in which fast breeder reactors would be operated as “fuel factories” providing the fissile material to power a number of lower-cost, high-efficiency CANDU reactors.
AECL has also undertaken assessment of fertile thorium fuel cycles. Development continues today, with reactor physics assessments of various once-through thorium cycles, fuel fabrication development, and irradiation testing of thorium based fuel in the National Research Universal (NRU) reactor. A variety of thorium cycles exists, all utilizing in one way or another the U-233 that is produced.
Another example of the flexibility of CANDU involves a proposed application of the CANDU system to eliminate plutonium and other long-lived fission products. Studies (Dastur, 1994) have indicated that plutonium and associated actinides could be used as a fuel in CANDU without the presence of uranium which is the source of these used fuel components. This eliminates the source of further actinides while annihilating existing waste actinides and by using them as fuel. A CANDU reactor of current design is projected to be capable of consuming the actinide production from 3 to 4 light water reactors. It is possible the actinide fuel can be replaced with conventional CANDU fuel without repercussions on reactor operation allowing continued energy production without dependence on actinide fuel.
In the very long term, spanning a few or many future generations, many other potential CANDU and other fission based energy development options are possible. Some have been the subject of scientific and engineering studies. Others will be identified, studied and implemented as practical by future generations as fossil and nuclear fuel resource usage and consequent economic conditions, change to support further exploration of energy opportunities.
One such scheme studied (Dastur, 1989) at Atomic Energy of Canada indicates that a rearrangement of the geometry of the fuel and moderator by alternating close and far spaced fuel assemblies in the core has the potential to triple (Dastur, 1990) the utilization of natural uranium in CANDU reactors without recycling. If proven practical this would be even more effective than using the synergistic relationship between the LWR and the CANDU to conserve uranium supplies. Since it uses natural uranium as fuel the energy intensive uranium enrichment process would also be bypassed.
A study of an accelerator breeder in conjunction with the CANDU reactor system was undertaken in 1980(Fraser). The system studied works by accelerating and impacting protons into uranium-plutonium or thorium-uranium fuel assemblies and was sized to serve as the fissile fuel supplier for CANDU reactors of 12,000 MWe capacity.
In summary, the CANDU reactor’s simple fuel design, high neutron economy, and on-line fuelling provide flexibility to respond to changing fuel-cycle requirements in the short term and in the indefinite future. There is great potential for developing supplementary processes by coming generations which will extract from earth’s nuclear fuel supplies the large quantities of energy which humans are able to usefully exploit for the preservation of a sustainable environment. Ample opportunity is available to future generations to secure energy to serve their needs while avoiding the major impact to the environment which is feared from current depleting energy sources.
CANADA’S NUCLEAR FUEL WASTE DISPOSAL CONCEPT
The IPCC noted public concern with respect to methodology for the long term disposal of nuclear waste. Methodology to sequester used fuel and nuclear fuel waste is well established in Canada.
In Canada, at present, used fuel discharged from nuclear power reactors is stored at the generating stations. This storage, either in water filled pools or in dry storage facilities, is a proven safe method of managing the waste for many decades at least. Storage facilities, however, need continued care and attention by people, and Canada, like other countries with large nuclear power programs, is seeking a disposal method that does not require human intervention to maintain safety.
Used nuclear fuel can be reprocessed to separate fissionable materials to be recycled. Although reprocessing is carried out in some countries, notably France, Japan and the United Kingdom, Canada does not currently reprocess used fuel. If Canadian used fuel is reprocessed in the future, the high level radioactive waste from the reprocessing operation would be incorporated in a solid matrix such as a glass. This is done at a commercial scale with light water reactor fuel in both France and the United Kingdom. Either the used fuel or the solidified reprocessing waste could proceed to disposal.
Because of the value of the electricity produced by a small amount of nuclear fuel, very elaborate measures can be taken to assure the safe disposal of the nuclear fuel waste. The estimated cost for disposal of nuclear fuel waste is about one-tenth of a cent per kilowatt-hour of electricity generated. This is about 2% of the cost of electricity to the consumer. Therefore, it is quite practical for the cost burden of waste disposal to be placed on the consumers of the electricity, thus providing sustainable energy production. The nuclear power generating utilities in Canada currently include the projected cost of disposal in the rates charged to their customers.
The most practical method of disposing of nuclear fuel waste is in a stable geological formation. Atomic Energy of Canada Limited, in partnership with Ontario Hydro, has developed and evaluated the concept of disposing of nuclear fuel waste 500 to 1000 meters below the surface in rock of the Canadian Shield. The used fuel or solidified reprocessing waste would be sealed in long-lasting containers, which would be placed underground, surrounded by sealing materials. Eventually all excavated openings in the rock would be backfilled and sealed to provide permanent, passively safe containment for the waste. The stable waste form, long-lasting container, sealing materials and rock would provide multiple barriers to the release and movement of materials.
After more than fifteen years of research on the disposal concept, AECL has concluded that a disposal facility would protect human health and the natural environment far into the future without the need for future generations to look after the waste.
The evidence (AECL) for this conclusion has been put forward for public review under the Federal Environmental Assessment and Review Process which takes into account broad social, political and environmental aspects of the concept. This process is expected to result in a recommendation to government, sometime in 1997, regarding the next steps to be taken for long-term management of Canada’s nuclear fuel waste.
CANDU SAFETY
CANDU reactors have had an exemplary safety record throughout the 25 years they have been in large scale commercial operation. Although some incidents have occurred at CANDU sites around the world, safety systems have responded as intended. The incidents have not resulted in large discharges of radioactive materials from the core into the containment safety system. There has thus been no detectable impact to the environment from any of these incidents. A more important observation, in the context of public concerns with reactor safety, can be made with respect to the inherent resistance of the CANDU design to the kind of accidents which occurred at the Three Mile Island and Chernobyl plants. Those accidents both resulted in substantial overheating of the radioactive core materials, and in the case of Chernobyl much of this was released to the environment. This release was due to the lack of a containment structure around the part of the reactor system which was failed by overpressure resulting from overheating fuel. The accident at Three Mile Island (TMI) was essentially terminated from the point of view of environmental impact by the reactors robust containment system.
CANDU reactors, by virtue of their separate low pressure moderator system adjacent to the reactor fuel and a shield water cooling system, are inherently fitted with additional sources of cooled water which can act to cool the reactor should other safety systems fail to perform as designed. In particular, analytic and experimental studies have shown that these systems provide effective heat sinks in the event of a loss of coolant accident accompanied by failure of the emergency core cooling system which contributed to the severity of the damage to the TMI reactor fuel. Early studies (Rogers, 1984) indicated the extra CANDU cooling systems could serve as independent “core catchers “ as long as cooling to them was maintained. Subsequent studies (Rogers) have provided additional confirmation of the capability of this safety feature. Full cognizance and appreciation of this safety advantage has resulted in modest design changes to current generation CANDU designs to enhance this inherent heat sink and severe accident prevention capability.
The TMI and Chernobyl accidents reinforced public doubt about the safety of nuclear reactors. That mistrust can only be allayed by continuing safe operation of nuclear plants. The CANDU system provides an extra measure of resistance to such accidents which will help to alleviate the public’s wariness of nuclear energy incited by those major accidents which should never have happened.
CANDU's ROLE IN GLOBAL DISARMAMENT
The flexibility which allows CANDU to be adapted to a wide variety of fuel cycles can also play a role in preventing the diversion of existing weapons grade material to nefarious purposes. Plutonium from existing weapons can be used as a fissile component in the fuel of existing CANDU reactors to generate energy. Any plutonium remaining in the fuel bundle is thus mixed with the highly radioactive products generated by the fission process rendering it very difficult to handle and process. The plutonium from weapons is thus rendered ineffective as a material for the production of additional nuclear weapons.
Under the first and second Strategic Arms Reduction Treaties (START I and START II) AND unilateral pledges by the United States of America and Russia significant quantities of plutonium from weapons are expected to be declared surplus to national defence needs (NAS). The dispositioning of this excess weapons grade plutonium has been the subject of intensive study in both countries for a number of years. The United States of America and Russia have undertaken joint programs of study and evaluation of options for management of excess weapons materials, in particular relating to safe and secure near term storage of surplus weapons material and options for utilisation in power reactors.
The primary goal of disposition is to render weapons-useable fissile materials inaccessible and unattractive for weapons use while protecting human health and the environment. In the United States of America five reactor-based plutonium disposition alternatives involving utilisation of mixed oxide fuel (MOX), two borehole alternatives for deep burial, and four immobilisation alternatives were selected as reasonable alternatives for further evaluation in the process of conducting a Programmatic Environmental Impact Statement (PEIS) for Long-Term Storage and Disposition of Weapons-Useable Fissile Materials (US DOE). The five reactor alternatives selected for further evaluation are existing Light Water Reactors (LWRs), including Pressurized Water Reactors (PWRs) and Boiling Water Reactors (BWRs), the Canadian CANDU reactors, partially complete LWRs, evolutionary LWRs, and an option termed EuroMOX. These alternatives, based on meeting the "spent fuel standard", are intended to make the excess weapons material as inaccessible as plutonium that normally exists in discharged irradiated fuel, and which is considered self-protecting because of the high radiation fields associated with power reactor spent fuel.
The Canadian CANDU reactor alternative involve conversion of weapons components into PuO2 powder and fabrication into MOX fuel at a facility or facilities located in the United States, followed by subsequent utilisation of the MOX fuel in Ontario Hydro's Bruce A reactors and subsequent emplacement of irradiated fuel in high level waste repository in Canada.
A detailed study of this option was performed in 1994 under US Department of Energy (DOE) funding. This study concluded that CANDU was a low cost option which could utilize a full-core of MOX fuel with essentially no major modifications to the reactor and minor modifications to the Bruce A station which involved the new fuel and discharged fuel handling systems (Boczar, 1995). Further study in 1996, also under US DOE funding established the feasibility of further optimizing the CANDU MOX fuel design such that the content of weapons-derived plutonium could be increased, thereby reducing the time required to complete the dispositioning mission.
Russia considers excess weapons fissile material as a valuable energy resource. Management of this material is the responsibility of the Ministry for Atomic Energy of the Russian Federation (MINATOM) and evaluation of options for utilisation of surplus weapons plutonium are being conducted by the Ministry (Yegorov). One such initiative involves evaluating the feasibility of fabricating MOX fuel at a facility in Russia for irradiation in Ontario Hydro's Bruce A reactors. The feasibility of this option has recently been jointly studied by Russia and Canada under Canadian funding and has focused on both the MOX fuel fabrication facility needs and transportation, safeguards and security issues relating to MOX fuel movement from the Russian fabrication site to the Bruce reactors in Ontario.
The results of these studies have clearly demonstrated the ability of CANDU nuclear power reactors to contribute positively to the process of global disarmament and to supporting international non-proliferation initiatives by utilizing both US and Russian excess weapons plutonium as MOX nuclear fuel in a parallel process of drawing down the material, thereby rendering this material both inaccessible and unusable in the future. This is also a significant and important potential application of CANDU nuclear power reactors to the further promotion of a sustainable energy regime.
SUPPORTING RESEARCH AND DEVELOPMENT
The foregoing discussion indicates the present performance and future potential of the CANDU energy system. Additional research and development is needed to refine existing systems and to bring them to long term realization. The CANDU program has been well supported by research facilities that are nearing the end of their useful life. Two research reactors (National Research Experimental and Whiteshell Research - 1) have been permanently shut down. A third, (NRU - National Research Universal) is 37 years old. It is Canada's only operating high-flux research reactor for power reactor fuel and materials research and for basic materials research using neutrons. This aging reactor is unlikely to operate much beyond the year 2000. Requirements for future irradiation facilities have been reviewed by Canada’s Natural Sciences and Engineering Research Council which has recommended that Canada give priority to funding and building a new Canadian neutron beam facility for materials research. In response, AECL is developing the concept for a national dual-purpose irradiation research facility.
One goal is to provide continuing access to irradiation facilities to develop and evolve the CANDU reactor system. (e.g., more passive safety systems, improved operation and maintenance, increased reliability, increased load factors, extended plant lifetime, and advanced fuel cycles) This requires suitable experimental facilities to test new concepts under CANDU reactor representative conditions. The detailed experimental requirements for the research facility were defined by consultation with CANDU designers, researchers and utility representatives.
The second goal is to provide a source of neutrons to materials scientists who use neutron scattering techniques. Neutrons provided by NRX and NRU have facilitated world-class materials research (e.g., the awarding of the 1994 Nobel Prize in physics to B.N. Brockhouse for his work on determining the excitation properties in materials, and developing inelastic scattering techniques and instrumentation (i.e., triple-axis spectrometer)). The neutron beam facility requirements are described by members (Buyers, Mason) of the Canadian Institute of Neutron Scattering and Committee on Materials Research Facilities (Bacon).
The research reactor concept, known as the Irradiation Research Facility (IRF) which has been defined on the basis of these requirements is described in considerable detail in recent publications (Lee, 1995,1996).
In the meantime development of fuel cycle enhancements is taking place in existing facilities.
For example, CANDU fuel fabrication trials have been conducted using simulated light water reactor spent fuel (i.e., unirradiated UO2 in which fission product surrogates have been added), as well as small quantities of actual spent fuel. An oxidation - reduction (Sullivan) process has been developed which reduces the spent fuel to a powder suitable for fabrication of CANDU fuel pellets. Pellets have been fabricated and will be assembled into fuel elements which will then be irradiated in Korea’s HANARO and Canada’s NRU research reactors.
AECL is also performing the reactor physics assessments of actinide annihilation systems. Non-fertile materials suitable as the material used in a CANDU like fuel bundle as the inert carrier material are under investigation (Dastur, 1993, Bultman)
AECL’s research program is thus geared to developing processes which can be developed economically in the short term, while making long term provisions for anticipated future needs through the development of replacement irradiation facilities.
DECOMMISSIONING NUCLEAR FACILITIES
Experience with decommissioning is still limited as most of the world’s nuclear plants are still in operation. However some early prototypes have been put out of service and some experience with the first stages of decommissioning has provided partial confirmation, and a basis for projecting costs, of subsequent stages of the process.
A recent independent review of the economics of environmental aspects of nuclear energy has been completed (Dewees) in Ontario, Canada by Professor Dewees of the University of Toronto Department of Economics. Professor DeWees examines cost estimates of decommissioning reactors in Ontario and elsewhere. This information is compared with estimates of costs based on actual costs incurred with the partial decommissioning of a nuclear plant, Gentilly 1, in the province of Quebec. He finds that there may be a degree of inconsistency in cost estimates and then compares the costs of decommissioning with the cost of electricity production. He notes that the estimated costs of decommissioning amount to “a fraction of 1% of the cost of electricity, so that even a fivefold increase in the estimated cost would not greatly affect the current operating economics of the reactors.”
Current regulatory standards in Canada require planning for future decommissioning. Applications for licenses require that this plan be submitted at the time of application. This planning exercise in conjunction with licensing and environmental assessment of the overall project ensures that the environmental and economic impact of decommissioning is accounted for early in the process. Measures are taken in the design of the plant to facilitate the decommissioning process and ensure a well planned route to economic decommissioning is available and accounted for in the licensing and environmental assessment.
CONCLUSIONS
We started with the observation of the IPCC that nuclear energy has the potential to provide an essentially carbon dioxide free energy source. We have reviewed several issues identified by the IPCC as reasons for the slow development of nuclear power and find them to be overemphasized, particularly with respect to the CANDU nuclear energy system. Wastes from this energy source will have little effect on earth’s life support systems as waste products are small in volume and can be shown to be readily sequestered from the environment. Reactors may be designed and operated safely to avoid accidents which affect the environment. CANDU reactors can even be readily adapted to transform the materials from dismantled nuclear weapons into a form which is difficult to use in major acts of terrorism.
Most importantly the discovery and development of nuclear fission energy provides a path to great amounts of energy for this and many future generations. Nuclear energy has been developed in a few decades to the point that energy can be provided now at a cost that is generally competitive with alternatives such as the fossil fuels. Nuclear energy essentially avoids environmental issues such as the potential for global warming which may interfere with sustained exploitation of fossil fuel energy sources. There is great and proven potential for future generations to continue refining the system to retrieve energy from fissile and fertile energy supplies on a sustainable basis. The CANDU nuclear energy system provides a particularly attractive means to exploit this resource in view of it’s simplicity and ability to adapt to future energy needs. We conclude that CANDU derived nuclear fission energy can meets the energy needs of current generations while enhancing the technological base which will allow future generations to meet their needs and that the essential requirements of a sustainable system are thus met.
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