Let's talk next about energy from nuclear fission, a major global generator of electrical power today and for the past 50 years. When radioactive elements such as uranium, thorium, and plutonium undergo the natural process of fission or radioactive decay, they are transformed into other elements while releasing vast amounts of energy. Let's join Osama Baig, nuclear engineer with Ontario Power Generation, for his explanation of how nuclear fission and electricity generation works. Start with nuclear fission. Fission reactions take heavy atoms like uranium, and they're split by energized particles called neutrons. Neutrons are like bullets, when they hit this heavier atom, the atom splits and releases a large amount of energy. This energy is coming from the atomic bonds that are holding this atom together. This large amount of energy is released because the atomic bonds that are holding this atom together are broken. Several other neutrons when that atoms broken are released and go on to the other atoms of uranium and a chain reaction starts, so continuous reaction, which exponentially increases. Now the question is, how is nuclear fission used to generate electricity? Once this meant energies is released from breaking these bonds, what takes place in a nuclear fission reactor? This energy can be used to heat water, create steam, and spin turbines. Chain reactions are really important in nuclear fission. Once these chain reactions are self-sustaining, so continually going on and on, the reaction goes into a phase called critical. This is the phase in which majority of reactors across the world, they run in a critical state. Nuclear fission generates electricity in a generation station where the heat from the fission reactor generate steam to turn a turbine, creating electricity. This is much like the generation process in a gas or coal fire generation station, but does not require combustion or creating greenhouse gas emissions. Nuclear power stations are typically large facilities with a capacity of 1,000 megawatts or more, enough to power a small city on their own. Back to our Sankey diagram to see how nuclear fission contributes to energy supply in today's world. Electricity is the only significant energy product from nuclear fission. Well, its contribution to electricity supply is far greater than any of the renewable sources, more than two times the combined output of solar, photovoltaic, and wind in 2019. It produces significantly less electricity than natural gas or coal. Nuclear energy is a key part of many electrical power systems around the world. Large nuclear plants provide base load electricity, always on stream, except went down for scheduled maintenance with very few unplanned outages. As a result, nuclear provides very reliable and predictable power output. It's always there, even when more intermittent sources cannot deliver. Nuclear generating stations produce a huge amount of power from a very small surface footprint. Older large nuclear plants have little flexibility and power delivery, taking significant time to power up and power down. But when their full output is not required, they can spill steam to reduce generation. New nuclear generation is more flexible and competitive within the demands of modern electrical grids. The first nuclear generating station came online at Calder Hall in England in 1956. Nuclear experienced rapid growth throughout the 1970s and 1980s, as it promised to supply an almost endless supply of very cheap electricity around the globe. That growth has slowed however, and at the end of 2020, there were 442 operating reactors fewer than existed in the year 2000. However, 52 more are under construction, most in China or in other developing nations. While nuclear still provides more than 10 percent of the world's electricity, its share of overall power generation has been declining for more than 20 years. Here's a graph showing total power generation by nuclear since 1970. The scale on the graph is in terawatt-hours. This is a measure of total electrical energy produced, not a measure of capacity to produce power. Rapid growth occurred as facilities were built primarily in Europe and North America during the 1970s and 1980s. But power output from those centers have been pretty stable since about the year 2000 as few new facilities were built. Note the big fall off a nuclear generation in Asia, the blue color in 2011, 2012, after an accident in Japan caused by an earthquake and subsequent tidal wave took the Fukushima station offline. Since then, Asian capacity has increased with new reactors in China and South Korea and a few Japanese reactors returning to service. We see in 2020, that the United States led world at nuclear power production, generating almost 800 terawatt-hours of electricity. With its recent nuclear construction program, China has overtaken France for second place, while Russia and South Korea both generated more than 100 terawatt-hours. Thirty-two countries produce electricity using nuclear in 2020. Looking at the proportion of electricity generated by nuclear in each country, we see quite a different story. Eleven European nations depend on nuclear for more than a third of their electricity, and 14 or 15 countries generating more than one-fifth of their power with nuclear are in Europe. Yet there's discussion within the European Union as to whether new nuclear construction can be regarded as sustainable. Germany at 11.2 percent nuclear in 2020, plans to close down all nuclear generation by the end of 2022. The International Atomic Energy Agency sees a wide range of scenarios in the future for nuclear energy. Anywhere between seven percent decline and greater than 100 percent increase by 2050. So much depends on how governments assess the positive versus negative attributes of nuclear energy. Let's look at the positive attributes of nuclear fission as a source of energy. Nuclear reactors provide uninterrupted base load electrical generation. They very reliably produce a steady flow of electrical power online more than 80 percent of the time over the past 20 years. Most of downtime is for scheduled maintenance work which is highly predictable and can be compensated for from other power sources. This chart from the National Renewable Energy Laboratory compares the life cycle greenhouse gas emissions for electricity generation for many different types of generators. Greenhouse gas emissions and pollution from nuclear energy are associated primarily with construction of the reactors and generating plants which consume large amounts of concrete and steel. While both materials are GHG-intensive, the associated emissions per unit of energy produced are small when one considers the immense amount of electricity generated by nuclear plant over its lifetime. There are also GHG emissions associated with mining, processing, and transporting nuclear fuel, but the quantities and associated emissions are also very small compared to the energy produced. The chart shows that total GHG emissions associated with nuclear power generation are very low comparable to renewable sources and much lower than fossil fuel generation. Reserves of uranium as shown in these fuel rods bundled from a nuclear reactor are abundant and widespread. Together with other elements that can be used to fuel nuclear reactions, these can support nuclear power generation for centuries. Nuclear generation stations can be situated near demand centers like the Pickering Nuclear Station just East of Toronto, Ontario thus reducing the need for electrical transmission lines and their associated power losses, but what about the negative attributes of nuclear power? A key issue is that it takes a long time to plan, permit, finance, and build a nuclear power facility in the United States and to a lesser extent in the UK and France. New nuclear facilities were originally built in less than five years, but as public apprehension about associated risks grew through the 1980s and '90s new facilities took up to 15 years and extreme cases up to 25 years to bring on stream. However, where most construction is happening today particularly China and South Korea regulatory burdens are less and timelines are much shorter on the order of five years. Nuclear radiation and perhaps more importantly, public attitudes towards nuclear radiation are major impediments to more widespread and quicker adoption of nuclear power. Concerns about safe containment of nuclear radiation whether in nuclear waste or because of accidents are justified by the deadly nature of radiation, however, excellent safety protocols are in place and nuclear power generation has caused fewer deaths per unit of energy produced than any other major energy source. As nuclear fuels have such high energy density, the volume of nuclear waste is very small, and that said there's a wide range of opinion on whether nuclear wastes can be safely and reliably managed in the future. Nuclear energy in the 21st century is much more than traditional large powered stations fueled by uranium, but there are many exciting new developments in making nuclear more flexible, nimble, and easy to build. Thanks Brad. Small modular nuclear fission reactors or SMR is for short offer the promise of addressing a number of the negative attributes of traditional large reactors while at the same time being more compatible with wind and solar the concept is not new with many designs prototypes there through the 1960s-1990s, but at the time could not really compete with large reactors in base load electricity markets. Let's explore these potential benefits in today's context. The comparative advantage is the opportunity to mass produce modularized smaller reactors in factories, thereby significantly shortening construction times and lowering individual reactor costs through production learning should more electricity be needed and other SMR module can be added. Secondly, SMRs have the potential to address a broad range of energy needs in the coming energy system transition. At last to estimate there are over 100 SMR designs in various stages of development and deployment worldwide. They're targeting a wide range of applications beyond nuclear energy's traditional role in base load power for a large electricity grids. These designs have energy outputs ranging from about a million watts or a megawatt to about 300 megawatts compared to a traditional reactors output of a billion watts or a gigawatt or more. Many designs are not just used for electricity generation, but also use the reactor's heat directly. For example, to replace fossil fuel use in industrial processes. Many SMR designs also allow for load following and for thermal storage of the reactors and heat so that the reactor can help electrical grids accommodate the intermittency of wind and solar. The smallest SMR design they're referred to as micro modular reactors or nuclear batteries, are ideal for off-grid and micro grid applications. For example, in Canada's Northern communities that are presently reliant on diesel for electricity generation. Many of these designs incorporate different reactor physics. Most large reactors slow down or moderate the neutrons produced from uranium fission using water as the moderator. Water is also used under pressure for a reactor cooling and heat transport. Conversely, many SMR designs do not moderate the neutron energy, and use of a variety of exotic materials for cooling and heat transport, such as molten salts, sodium, and even helium. Many designs operated atmospheric pressure. What are the benefits? Well, one benefit is simpler designs with inherent safety at lower costs. For example, having no reliance on offsite power. Second is higher output temperature is up to even 1,000 degrees Celsius, thereby increasing their suitability for use in industrial processes, and finally, many designs use up the long-lived radioactive actinides produced during nuclear fission, thereby reducing radioactive waste streams. How many of these designs are now in first of a kind demonstrations in several nations, including here in Canada, with deployments to quantity now ramping up in some nations, most notably China. Several Canadian provinces have agreed to cooperate and the development deployment of SMRs for multiple markets. Let's exam finally, some of the cautions regarding the potential for SMRs to be a big contributor to the global energy system transition. The economics of SMR is depend on realizing the benefits of production learning through mass production of simpler, standardized designs deployed in global fleets, and turn this requires harmonized regulation across nations. This economic models are referred to as economies of multiples. An example would be how the global civil airlines sector operates with a relatively small number of standardized designs operated by many airlines according to internationally accepted safety standards. These changes towards standardization and Regulatory Harmonization speak to the need for a paradigm shift in how nuclear new build programs are delivered compared to current practices. The second caution arises when we look at the totality of the infrastructure required to support an SMR deployment. This SMR system includes a fleet of SMR potentially deployed across multiple nations and jurisdictions with multiple operators, with enabling infrastructure including factories for module construction and in some cases for fueling, for nuclear fuel production, and in some designs for fuel reprocessing, and finally for radioactive waste management and there's transportation of nuclear materials between the many nodes in the system. The list of stakeholders with say in the choice of system and siting of these components. Include a potential host communities, indigenous rights holders, a national regulators and more. While there is a clear urgency to transition the global energy system towards a net-zero future. There is simply no shortcut to the need for building social license. Simply stated, for SMR is to be a significant contributor to the global energy system transition. The world will need many SMR. Indeed, in the many thousands where today's large nuclear plants tend to be out of sight for much of the population. SMRs deployed in the quantities required would be much more likely to be in someone's backyard. We see the imperative to engage meaningfully with the public and with the many SMR stakeholders. There is much to be learned from the social sciences and how to address the public's than nuclear or hesitancy. In particular, in the face of growing societal and political polarization, social media and misinformation and eroding public trust in governments and institutions. The bottom line now is the time to be doing so. To wrap up this lesson, let's go back to Osama Baig this time to tell us about nuclear fusion, how it differs from fission, and how it could be a big energy generator in the future. Nuclear fusion reactions are pretty much the opposite of nuclear fission reactions. Instead of splitting a heavier nuclei, you're actually taking two lighter atoms and bringing them together to make them fuse. This reaction, it takes place in really hot intense heat environments like our Sun, where the core of the Sun is where fusion takes place, where nuclear come together and combine and produce massive amounts of heat and energy released in the form of light, heat, radiation, bread. So it's been very, very powerful reaction. How does fusion take place? Fusion can take place with many different atoms in the periodic table. But right now, scientists and researchers across the world are focusing on deuterium tritium fusion, and the reason why is because deuterium tritium fusion has the ability to produce that large amounts of energy at lower temperatures, which compared to other atoms, require a lot higher temperatures for atoms to fuse. In short, it's easier for that reaction to take place. Fusion reactor designs currently do exist, like the topo map or the stellarator. There's many different designs out there to go to the process, and there's a bit of a race in the world right now to develop a self-sustaining reaction. Self-sustaining reaction, meaning fusion, ignition. That's when the amount of energy that is being produced is sufficient or sustainable enough to produce electricity. That's the end goal. We want to use fusion reactions to create electricity which can power entire nations. Thanks Osama. There are certainly exciting roles for nuclear energy, fission and possibly fusion to play in the generation of electricity. Next, we're going to examine renewable energy sources, starting with hydroelectricity.
