By Andrew Farris
Nuclear power plays an important role in electricity generation across the world, and over 443 nuclear power plants are in operation.
The basic workings of nuclear power are fairly straightforward: A nuclear reactor produces energy by nuclear
Although in the early days of its development during the 1960s and 1970s, nuclear power plants were built rapidly, public attitudes to it have cooled. Since the Chernobyl nuclear meltdown in 1986, few new nuclear power plants have been built and there has been staunch opposition to any new plant proposals. The situation is not static though. Instability in fossil fuel prices and concerns about global warming have driven a renewal of interest in nuclear power among policy-makers and investors.
Though negative public perceptions about nuclear safety are not entirely deserved, the nuclear industry can never offer a complete guarantee against another nuclear accident.
Nuclear power begins with the mining of a reactor's fuel: uranium. Uranium is a naturally occurring and relatively commonplace metal—there is about as much of it around the world as tin. Uranium will occur in ores with a grade that can be as high as 20% in some cases, though it can be economical to mine ores with grades as low as 0.02%.
Once uranium is extracted from the ground, either from an underground or a surface mine, it must go through a complicated refining process. Most mines use on-site crushers to grind up the ore and use a combination of sulfuric acid, settling tanks, and ion exchangers to separate uranium from rock tailings. The result is a precipitate of uranium, which, when dried, becomes a uranium oxide (U3O8). This uranium is not enriched and only mildly radioactive. It is known as yellowcake.
At this stage, most nuclear reactors in the world require that the mined uranium must be enriched, so that the fissionable U-235 isotopes go from their naturally occurring 0.7% to around 20%.
Before enrichment can take place, the yellowcake must be converted into a gas: uranium hexafluoride. Now the uranium is ready for enrichment. Enrichment involves using rapidly-spinning centrifuges which can separate out the heavier uranium-235 atoms.
Enrichment is expensive, adding up to about half the total cost of nuclear fuel. Once uranium has been enriched it is ready to undergo nuclear fission.
Nuclear fission is the splitting of unstable atoms, typically
How is this heat harnessed by a nuclear reactor? The example we will use is a Boiling Water Reactor (BWR), the second most common type of reactor in the world and the primary reactor used in the United States, Japan and many European countries. For more information on the other reactor types, and Canada's own reactor design the CANDU, we will soon be adding a new supplementary article. Usually uranium is enriched with U-235 to form around 20% of the nuclear fuel. This uranium fuel is manufactured into small pellets that are themselves arranged into bundles of fuel rods. Typically the fuel rods will be submerged in water inside the reactor core. This serves three purposes.
First the water can act as a
Secondly, the water is a coolant. It is imperative that the reactor stay submerged in water to help cool the fuel bundles, otherwise they would overheat and melt. This is a nuclear meltdown, and can lead to the uranium fuel burning through the floor of the reactor and exposing dangerous radiation to the outside environment. Reactors have a number of safety precautions to prevent meltdowns from happening, but meltdowns have occurred several times in the fifty years of civilian nuclear power use. It was once thought that the nuclear fuel, if left uncooled, would get so hot it would continue melting into the ground and pass through the entire earth, reaching China, hence the name China Syndrome. This is of course absurd, but exposed nuclear fuel rods do pose a grave risk to those around them. .
Thirdly the water is boiled off, and the steam is used to spin a turbine. That turbine is connected to a generator which generates electricity.
Nuclear power plants can be built essentially anywhere they can access the large amounts of water needed for cooling, anywhere from 95,000 to 227,000 litres per MWh of power generated.
One geographical issue that has come into sharp focus in the aftermath of the Japanese earthquake and tsunami are the threat that natural disasters pose to nuclear facilities. The Fukushima 1 nuclear accidents in March 2011 resulted from the cascading failures of a number of fail-safes intended to prevent nuclear meltdown. Many nuclear reactors are built in earthquake-prone areas, especially in Japan, and many are built at the water's edge. Though Japan's plants have operated without serious accidents since the 1960s, they can be uniquely vulnerable to the one-two punch of an earthquake and tsunami. Over a dozen countries including China, Switzerland and Finland are reviewing their safety precautions in light of these events. Germany has already announced it will close all of its nuclear power plants by 2022 as a direct result of the events at Fukushima, though the geographical conditions that led to the Fukushima disaster do not exist in Germany.
After the first nuclear plant was connected to the civilian electric grid in the Soviet Union in 1964, hundreds of of nuclear power plants have been built and operated around the world, amounting to over 14,570 cumulative reactor years of operation.
While nuclear power is important to many major economies, only one relies upon nuclear power for more than half of its electricity needs: France. Following the Arab oil embargo in 1973, the French sought to secure their energy independence by aggressively embracing nuclear power. As a French slogan went at the time: "No coal, no oil, no gas, no choice." Today, France operates 68 nuclear reactors that provide the country with 75% of its electricity.
In the next decade, global nuclear power capacity is set to expand due to the economic rise of China and India. These countries are only in the initial stages of developing civilian nuclear energy capabilities and as of July 2011 Canada still produces more megawatts of nuclear power than the two combined. But the two energy-hungry economies are catching up at an astonishing pace. China already has 27 nuclear reactors under construction, and 160 more in various stages of planning according to the World Nuclear Association. India is building 5 and is planning another 58.
Ever since the beginning of the nuclear age, Canada has been at the forefront of nuclear power development. The country's first civilian reactor opened in 1971, and today Canada operates 18 of them: 16 in Ontario, and one each in New Brunswick and Quebec.
Most of Canada's plants were built in the 1960s and '70s, and will be reaching the end of their service lives in the next decade. A plant's 30 to 40 year service life is determined by the wear and tear many essential parts in the plant will suffer over that time period, which could potentially compromise the safe operating of the plant and the safety of its workers.
Plans have been in the works for some time to build two new reactors at the Darlington plant. The four reactors at Darlington currently provide Ontario with 3,512 MegaWatts of power, about 20% of its electricity. These plans were suspended after the only company to make a bid, Canada's flagship nuclear power company AECL, announced they could only build the plants for double the province's allotted budget. This was not good enough for Ontario's government and the construction of new plants is currently on hold. The frequent cost overruns and poor sales in CANDU reactors in the past five years has led the government to auction off part of the crown corporation AECL to a private Montreal-based engineering firm, SNC-Lavalin.
In the West, Alberta is tentatively considering using nuclear fission to help oil sands extraction. There are two broadly similar techniques that could be used, known as cyclic steam stimulation (CSS) and steam-assisted gravity drainage (SAGD). Both essentially require water to be heated, turned into steam and pumped underground. This will heat the
The Alberta government maintains that though it is not actively encouraging such plans, it will consider applications from private companies. Typically, the massive long-term investments required to build a nuclear power plant require close cooperation and subsidization from government. The Alberta government's low-profile approach might then be a factor in Bruce Power's decision to wait and see how market conditions in the oil sands develop in the years ahead. It is also addressing concerns about any threat of water contamination of the Peace River. At this pace it is unlikely a nuclear power plant in the tar sands could come online before the decade is out.
British Columbia has never had a nuclear power plant or an uranium mine. Until now, there has not been an outstanding need for this source of energy in the province. BC currently generates 86% of its electricity from hydroelectric power, and the potential exists to generate triple that.
In light of this, the B.C. Government was in a position to reiterate its desire to avoid nuclear power in the 2010 Clean Energy Act, which aims to "achieve British Columbia's energy objectives without the use of nuclear power."
Canada is the world's second-largest uranium producer behind Kazakhstan. Canada also hosts some of the biggest reserves with close to 500,000 tonnes of uranium recoverable, though it is well behind Australia (1,673,000 tonnes) and Kazakhstan (651,000 tonnes).
After a geological study in 2008 the Boss Power Corp. applied for the rights to begin an environmental survey for a uranium mine approximately 50 km south-east of Kelowna at a site they called the Blizzard deposit. Three days later on April 21, the government, belatedly realizing uranium mining could actually happen in the province, issued a ban not only on uranium mining, but on exploration for it as well.
Boss Power has since argued that the government unlawfully expropriated the land at the Blizzard site, without providing a legal and scientific basis for the moratorium. The company sued the province for compensation and in April 2012 Boss Power received a $30 million settlement from the government out of court, a move that was controversial since it greatly exceeded the provincial government's own estimates of how much money Boss Power could reasonably claim to have lost on the investment.
The Renaissance on Hold?
The study postulated a scenario where the 336 reactors, then in operation, would multiply to anywhere from 1,000 to 1,500 globally by mid-century. This could, with the aid of renewables and energy efficiency improvements, eventually replace the fossil fuel economy. In order to achieve this rapid growth, four problems needed to be seriously addressed in the next decade: economic competitiveness, proliferation, dealing with radioactive waste, and safety.
Seven years on and unfortunately, none of these problems are anywhere near being solved. The study points out that, as of 2003, nuclear power was not economically competitive with fossil-fuel based forms of electricity generation. Without a carbon tax it is unlikely it ever will be. Since then, despite the fact that fossil fuels have become more expensive, nuclear power has not benefitted. Instead it continues to be handicapped by high construction costs and economic uncertainty. A few major economies implemented carbon taxes, such as India, South Korea and the European Union, but the biggest emitters, China and the United States, have not.
As for the proliferation of radioactive materials to terrorists or rogue states, the record is equally bleak. North Korea has detonated two nuclear warheads since 2006, while that country's domestic and diplomatic situation is anything but improving. And despite repeated attempts, the international community is looking increasingly powerless to stop Iran from acquiring a nuclear bomb. Pakistan, with over 100 nuclear warheads, is experiencing alarming political instability.
As for nuclear waste, though many countries are planning to seal it deep underground, these plans have been hit by setbacks and controversies. The most notable example is America's Yucca Mountain. Intended as the nation's nuclear waste repository since 1991, the project was entirely cancelled in 2009 thanks to a sustained opposition campaign from local residents and environmentalists. On the other hand, Finland and Sweden have finally selected sites for their repositories in communities that have volunteered for the site, providing some encouragement to the nuclear industry.
The final issue—nuclear safety—occupies a lot of headlines. The crisis at Fukushima, though not currently anticipated to cause widespread death or illness, has shown that even advanced economies like Japan, with unequaled experience dealing with natural disasters, cannot fully contain the risks inherent to nuclear power. The crisis has caused the International Energy Agency to halve its estimated increase in nuclear capacity by 2030 and lead a number of countries to review their nuclear safety procedures and expansion plans.
For these reasons the plan to use nuclear energy as a central plank of a global climate change strategy appears in doubt.
Is nuclear power economical? The answer depends largely upon the market conditions. As a general rule, nuclear power plants are more expensive to build and decommission than other power plants, but less expensive to operate.
For its weight, uranium is comparatively expensive. To mine the uranium ore, convert it, enrich it and fabricate a kilogram of reactor fuel costs about $2,500. Although that might sound expensive, a kilogram of enriched processed uranium can be used to generate more energy than any other substance yet harnessed by mankind—about 360,000 kWh per kilogram, 20,000 times more energy than a kilogram of coal. Taking the fuel alone, the price of nuclear power is about 0.77 cents per kilowatt hour. Including operating and maintenance costs, this rises to just over 2 cents per kilowatt hour, which is far cheaper than any fossil fuel form of power, as evidenced by this graph.
In comparison with coal, nuclear fuel is more compact, the mining operations are not as vast and intensive (and potentially less environment disruptive), the ore is easier to transport, and since the fuel is only a small part of the cost of providing nuclear power, it's not as vulnerable to major price fluctuations. This final advantage makes nuclear power attractive amid ongoing supply challenges and cost increases in fossil fuel markets. Spent uranium fuel can also be reprocessed and reused as fuel in certain types of reactors.
Just like any other finite resource however, uranium deposits are limited and will eventually be exhausted. However, at current consumption rates uranium reserves can be expected to last about 230 years. We can also reasonably expect that new extraction and enrichment technologies can extend this time considerably. A near-term shortfall may be looming as supplies of uranium from decommissioned Russian and American nuclear weapons, which accounted for 44% of all nuclear fuel used in 2007, are expected to be fully utilized by around 2015. This has given some incentive to exploration and mining companies to make up for the shortage.
Uranium deposits are also not located uniformly around the globe, which can lead to geopolitical tensions between countries that possess uranium, and those who do not. This is not currently a serious issue as there are deposits on almost every continent and no major economies have yet found themselves cut off from supplies of uranium. The OECD countries have friendly suppliers in Canada, Australia, Niger and Namibia, while Russia and Kazakhstan's production is relied upon by China, India and Russia.
The economic problems with nuclear power revolve around plant construction, technical expertise, waste and reprocessing, and legal hurdles that nuclear energy faces in many countries. For starters, nuclear power plant proposals in OECD countries must address local concerns in extensive consultation and regulatory processes that can dissuade potential investors and projects. Once construction begins, extensive safety measures, back-up equipment and special materials that ensure the highest levels of safety possible add considerably to capital costs. This also means a new plant can take up to a decade to license and build.
As the Wall Street Journal recently reported, several other problems are handicapping any proposed new nuclear plant construction:
Historically nuclear power plants have been prone to cost overruns and delays. The Darlington nuclear power plant in Ontario is cited internationally as a example. Started in 1980, it was only completed 13 years later approximately 300% over budget at a final tally of $14.4 billion.
A changing utilities market is also complicating the expansion nuclear power. To make a nuclear power plant an attractive investment, there must be a guaranteed market to justify the massive up-front price-tag and long-term logistical effort. These conditions were satisfied in the 1970's and 1980's as government-owned utilities exercised monopolies. Today many jurisdictions are increasingly privatizing their power companies and opening up the private sector market to competition and investment. In this atmosphere, it is difficult to convince investors of the appeal of spending $10 billion for nuclear power plant project that will come online in a decade. This contrasts with a competitive coal-burning plant that can be built and put in operation in a fraction of the time.
Finally after the nuclear plant is constructed, large sums of money have to be set aside for safely dealing with nuclear waste and eventually decommissioning the plant after it runs through its life-span, usually around 30 years. In the United States the Nuclear Waste Fund, paid by electric utilities that use nuclear power, runs to nearly $750 million a year.
Though nuclear fuel is comparatively cheap (on a per kWh basis) and relatively abundant, the plant itself is time-consuming to build, unpopular with the public, and difficult to put an accurate price tag on.
The environmental factors involved in nuclear power are perhaps more complex and controversial than the economic ones. Nuclear power is often touted as a necessary part of any climate-change fighting strategy because a nuclear reactor has a very small carbon footprint. But if we factor in the carbon emissions associated with the plant's construction, the mining and processing of the uranium, does the footprint increase substantially? And does a correctly operated plant pose a threat to human health? What happens when a catastrophic meltdown occurs like at Chernobyl or Fukushima? And can the vexing problem of nuclear waste ever be solved? Let's examine each of these questions in turn in order ascertain nuclear power's real environmental credibility.
It is clear that given the enormity of the task of dealing with climate change, a number of carbon-mitigating measures are going to be needed, and though controversial, nuclear power must be considered. The UN's Intergovernmental Panel on Climate Change says that over its entire life-cycle a nuclear power plant will emit a similar amount of carbon to renewable energies (40 grams of carbon -eq/kWh) and therefore nuclear is "an effective [Green House Gases] mitigation option, especially through license extensions of existing plants enabling investments in retrofitting and upgrading."
Since building the plant, mining and enriching the uranium, and dealing with the nuclear waste are all activities that emit carbon, you may wonder how a nuclear reactor could possibly emit a comparable amount of carbon over its life-span to say a wind turbine. The difference is the scale. A typical nuclear power plant generates around 1,000 MW of electricity. Today the largest wind turbine in the world, at 198 m tall (about the same height as the tallest building in B.C., the Living Shangri-La in Vancouver), generates about 7 MW of power.
We should note that most humans are exposed to some amount of nuclear, or ionizing, radiation on a regular basis. The average North American annually receives a dose of approximately 360 mllirems of radiation, primarily from cosmic rays. This is the equivalent of 36 plain chest or dental X-rays each year. Medical imaging is a significant source of the dosage, but low, yet continual doses can be emitted from natural substances, e.g., in rocks, soils or radon gas. Many manufactured goods, such as paper, clothes and even food, can have radioactive elements in them that emit radiation to which we are exposed. The lowest radiation dose that is thought to be a health threat is about 100 mSv in a year, which can cause a slightly heightened risk of cancer later in life. The average person living within 80km of a nuclear power plant is exposed to around 0.0001 mSv a year that can be attributed to the plant. Most people are exposed to about 0.28 mSv a year from cosmic rays.
Assessing the health threat of a nuclear power plant changes entirely when one takes into account the risk of catastrophic radiation releases into the environment. The International Atomic Energy Association has developed a 7-level scale to rank the scale of a nuclear accident leading to the release of radiation. Since the first deployment of civilian nuclear power there have been three Level 7 accidents:
- Three Mile Island in the United States
- Chernobyl in the former Soviet Union
- Fukushima in Japan.
The only site to result in any directly attributable deaths was Chernobyl. We will discuss these disasters further in a supplementary article to be added shortly: how they happened, what damage they caused and what the potential is that another could occur at one of the world's 443 nuclear power plants.
Nuclear waste is a major challenge for the nuclear industry. The most dangerous nuclear waste, which scientists estimate must be cooled and shielded from the outside world for tens of thousands of years, are the spent fuel rods (See: How Nuclear Power Works). They contain a number of radioactive isotopes that result from nuclear fission and have varying half-lives, and therefore varying degrees of danger. Iodine-131, for instance, has a half-life of eight days, meaning every eight days it loses half of its radioactivity and after a short time will no longer pose any danger to living things. Iodine-129 on the other hand has a half-life of 15.7 million years.
The problem poses a unique ethical dilemma: does our need for energy outweigh the multi-generational commitment we are making in storing this potentially hazardous waste? Can we be sure that the tremendous volumes of radioactive material do not fall into the wrong hands or leak into the atmosphere after an earthquake? It is, after all, impossible to know who or what will be living on Earth in 100,000 years; our oldest civilizations are a mere 6,000 years old. We can perhaps, try and explain the threat to them. At least that's the strategy undertaken by the United States. Their Department of Energy had planned (until recently) on burying their 56,000 tons of nuclear waste below Yucca Mountain, Nevada. Around the site they planned on erecting a wall of salt, 48 monoliths with warnings written in English, French, Russian, Arabic, Chinese, Spanish and Navajo, burying thousands of tiny placards around the area, as well as several buried information centers that employed pictograms to scare away any potential future explorers or archaeologists about the dangers that lay within the mountain.
New plants, like the Generation IV plants that are forecast to begin coming online around 2030, will be able to extract energy from a number of radioactive isotopes, and from very diluted quantities of radioactive ores. In fact this means that the nuclear waste created by plants today could be reprocessed and burned in these new reactors. This is why many countries are actually reluctant to bury their nuclear waste in some inaccessible underground vault: that waste may one day be invaluable power plant fuel. This is certainly the case with France, and they appear willing to sit on their nuclear waste until these new plants come online and their waste can be reprocessed again into fuel. The waste created by these new plants will not be nearly as dangerous as that from current, more primitive designs.
Though Canada has not yet begun planning such elaborate Stonehenge-like precautions for its nuclear waste, the government has been slowly moving forward on the issue of long-term storage. Currently all of the country's nuclear fuel is stored on-site at nuclear plants in concrete-lined holding pools under three metres of water. This is sufficient to block the harmful radiation effects of the waste and after seven to ten years the fuel bundles have cooled enough to be moved to a dry storage facility. Since each plant produces on average about 27 tons of nuclear waste a year, the amount is adding up quickly.
In 2002 the Nuclear Waste Management Organization (NWMO) was created and tasked with deciding what Canada should do with its mounting radioactive stockpiles. The NWMO has recommended a deep geological repository, perhaps in the stable granite formations of the Canadian Shield. There is no timeline to choose a site and the organization recommended taking a gradual approach that builds consensus with all interested parties. The organization is currently designing a process to select a site. Though the rock formations of the Canadian Shield are some of the most ancient and geologically stable in the world, it is impossible to guarantee that any repository site will remain locked away for the thousands of years necessary to let the radioactivity decay away. If the site were to be breached at any point in perhaps as long as 100,000 years, it could prove lethal not only to whoever or whatever is living in the immediate vicinity but for vast distances around. Many opponents of nuclear power question whether this future uncertainty is too high of a price to pay for nuclear power today.
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