Is Nuclear Energy Inexhaustible?
Nuclear energy is energy released by the splitting of atoms in a process called nuclear fission. Nuclear power plants use nuclear fission to produce electricity. https://www.kiplinger.com/article/investing/t038-c000-s002-a-brief-history-of-nuclear-power.html
The first nuclear power plant opened in the 1950s. As of 2022, there are about 440 nuclear reactors operating in 32 countries around the world, producing about 10% of the world’s electricity. The United States has the most operating nuclear reactors with 93, followed by France with 56. However, some countries like Germany and Switzerland have been phasing out nuclear power following the 2011 Fukushima nuclear accident in Japan. Overall, the share of nuclear power in the global energy mix has been declining slowly in recent years.
Nuclear Fuel Supply
The most common nuclear fuel used in reactors today is uranium. Uranium is a naturally occurring element that can be mined from the Earth’s crust. According to the World Nuclear Association, at present rates of usage, the world’s present measured resources of uranium are enough to last for over 100 years[1]. However, this only accounts for uranium that has already been discovered. With continued exploration and improvements in extraction technology, uranium resources could potentially last for thousands of years.
Some key facts on uranium supply[2]:
- Identified uranium resources have increased by over 50% in the past decade due to new discoveries and rising prices, making more deposits economically viable.
- Less than half of the uranium found in standard mines comes from actual uranium deposits; the rest comes from the oceans and as a by-product of other mining operations.
- Uranium can also be extracted from seawater, which contains over 4 billion tonnes. However this is currently not economically viable.
- Breeder reactors could potentially “breed” more fuel than they consume if reprocessing technology is utilized.
In addition to uranium, thorium is another potential nuclear fuel. It is 3-4 times more abundant than uranium[3] and could significantly extend nuclear fuel reserves. However, thorium is not readily usable in most existing nuclear reactors.
While uranium supply is seen as adequate for now, nuclear proponents argue that fuel efficiency could be dramatically improved to extend supply for millennia. On the other hand, critics argue that economically extractable uranium is more limited and shortages could occur if nuclear power is significantly expanded.
[1] https://www.world-nuclear.org/information-library/nuclear-fuel-cycle/uranium-resources/supply-of-uranium.aspx
[2] https://www.youtube.com/watch?v=uXVuhLJQpLg
[3] https://bettermeetsreality.com/how-much-uranium-is-left-in-the-world-on-land-in-oceans-when-will-we-run-out/
Nuclear Fuel Efficiency
One of the key factors determining how long nuclear fuel supplies will last is the efficiency of fuel burn-up in reactors. Fuel burn-up refers to the amount of energy that can be extracted from a given amount of nuclear fuel before it needs to be replaced. Over the decades, advances in reactor design and fuel technology have steadily increased burn-up rates, allowing more power to be generated from the same amount of fuel.
According to a 2010 review, the “high burn-up structure” that forms in nuclear fuel pellets during irradiation allows for much higher fuel burn-ups than originally thought possible (Rondinella et al., 2010). Whereas burn-up rates in the 1960s were 10-20 gigawatt-days per metric ton of heavy metal (GWd/tHM), current light water reactors now often achieve burn-up rates of 50-60 GWd/tHM. Some fuel assemblies have been demonstrated to reach burn-up rates as high as 100 GWd/tHM.
Improvements in fuel rod and cladding materials, as well as innovations like adding a thin layer of zirconium lining to the fuel rod cladding, have enabled these substantial increases. These advances have dramatically extended the functional lifetime of each fuel assembly and improved the economics of nuclear power by reducing the frequency of fuel replacements.
Nuclear Waste and Recycling
Nuclear waste is one of the biggest issues surrounding nuclear power. Nuclear reactors produce spent fuel that is highly radioactive and remains dangerous for thousands of years (1). There is currently no permanent storage solution for this waste in most countries using nuclear power, so it is kept in interim storage facilities.
Reprocessing spent nuclear fuel to recover unused uranium and plutonium is one strategy used in some countries like France and Russia. The recovered materials can be recycled into fresh fuel. However, reprocessing is complicated and expensive. There are also concerns about proliferation risks from separating plutonium (2).
Breeder reactors are another proposed solution for better utilizing nuclear fuel and reducing waste. Breeder reactors can create more fissile material than they consume, amplifying the energy extracted from uranium by nearly 60 times (1). However, breeder reactors are not yet commercially viable.
Most countries today use an open fuel cycle where spent fuel is not reprocessed, but research continues into closed fuel cycle options to better utilize nuclear materials and deal with waste (2). Finding acceptable long-term solutions for existing and future nuclear waste remains an ongoing challenge for the industry.
(1) https://www.azocleantech.com/article.aspx?ArticleID=1751
(2) https://www.cnbc.com/2022/08/16/curio-led-by-energy-dept-veteran-aims-to-recycle-nuclear-waste.html
Safety and Accidents
The nuclear energy industry has an excellent safety record, with very low risks of accidents in nuclear power plants. According to the U.S. Nuclear Regulatory Commission (NRC), the industry safety accident rate in the U.S. declined to 0 in 2018 and 2019 (Statista). The NRC oversees strict regulations and procedures to minimize risks. Nuclear reactors have multiple robust layers of defense to contain radiation in the unlikely event of an accident.
Nevertheless, there have been major nuclear accidents that have caused significant damage, most notably the Chernobyl disaster in 1986 and the Fukushima accident in 2011. The Chernobyl accident in Soviet Ukraine was caused by a flawed reactor design and human error, resulting in an explosion and widespread radioactive contamination. The Fukushima accident in Japan was triggered by a massive tsunami that knocked out emergency generators needed to cool the reactors and contain radiation (World Nuclear Association). These major accidents have led to improved safety regulations and training.
While the risk of future accidents can never be eliminated entirely, the nuclear industry continues to implement enhanced safety measures and learn from past disasters. With proper safeguards and oversight, nuclear power plants have demonstrated an ability to operate safely for decades.
Costs
The costs for nuclear power plants are very high compared to other energy sources. According to one estimate, a new 1 gigawatt nuclear reactor can cost around $11.5 billion to build (Source). This makes nuclear power plants some of the most expensive energy infrastructure projects.
In terms of cost per kilowatt-hour (kWh), nuclear is more expensive than energy from natural gas, coal, hydroelectric and onshore wind. However, it is cheaper than solar power. One estimate puts the cost per kWh for nuclear at around $112, compared to $42 for natural gas and $37 for coal (Source).
The high initial construction costs, as well as costs for operations, maintenance, waste management and decommissioning contribute to the high price per kWh for nuclear power. While nuclear does provide reliable baseload power, the costs make it less economically competitive than other sources.
Proliferation Risks
There are legitimate concerns that expanding nuclear power worldwide could lead to greater weapons proliferation. Nuclear technology and materials used for civil purposes can potentially be diverted for military uses. According to the American Academy of Arts and Sciences, over 40 countries currently have the technical capacity to produce nuclear weapons if they chose to.
Some argue that limiting access to nuclear power is essential to curb proliferation risks. However, others contend that providing nations with nuclear energy alternatives makes them less likely to pursue indigenous nuclear weapons programs. The spread of nuclear technology is difficult to control, so policies must balance nonproliferation goals with supporting clean energy development.
There are ongoing diplomatic efforts to convince countries to forgo nuclear weapons and comply with nonproliferation treaties. But ultimately, managing nuclear proliferation dangers requires building trust between nations and strengthening international security cooperation.
Environmental Impact
Nuclear power has clear environmental benefits over fossil fuel power plants in terms of carbon emissions and climate change. According to a Sprott report, without nuclear power, carbon emissions from electricity production in the U.S. would have been substantially higher over the last 40 years (https://sprott.com/insights/special-report-uranium-nuclear-power-play-a-critical-role-in-the-us/?alttemplate=printblogarticle). Nuclear plants emit almost no greenhouse gases or air pollutants during operation. The complete nuclear power chain, from uranium mining to waste disposal, emits only 2-6 grams of carbon dioxide per kilowatt-hour. This is comparable to wind and solar power.
In terms of land use, nuclear plants require much less space than utility-scale solar or onshore wind farms. A 1,000 megawatt nuclear facility needs about 1-4 square miles of land. An equivalent solar PV plant would require over 40 square miles, while wind farms need over 260 square miles. Therefore, nuclear power can generate large amounts of electricity without occupying excessive land area that could disturb natural habitats.
Current and Future Outlook
Nuclear power currently provides around 10% of the world’s electricity, but its future growth prospects are uncertain. According to the MIT study on The Future of Nuclear Power, nuclear capacity could potentially double or even triple by 2050 if new reactors are built to replace retiring plants. However, growth has been slower than anticipated due to factors like high construction costs, public opposition, and competition from renewables.
The role of nuclear power in the clean energy transition is debated. Some argue it provides steady, low-carbon baseload electricity to complement intermittent renewables like wind and solar. Nuclear advocates claim that rapidly decarbonizing the power sector will be extremely challenging without retaining existing nuclear plants and building new ones. Others argue that alternatives like renewable energy storage, demand response, and energy efficiency improvements can displace nuclear while also achieving emissions reductions goals. Countries like Germany plan to phase out nuclear entirely while still reducing emissions through high shares of renewables.
The future of nuclear will depend heavily on policies and choices made country-by-country. Strong government support and subsidies could drive nuclear growth in places like China and Russia. But aging reactors are continuing to retire in nuclear-dependent nations like the U.S. and France, and once-ambitious new build plans have been scaled down. While nuclear power will remain an important low-carbon electricity source for the foreseeable future, its long-term prospects are clouded by unresolved cost and waste issues.
Conclusion
In conclusion, nuclear energy cannot truly be considered inexhaustible due to limitations in fuel supply and efficiency. However, nuclear fuel reserves are abundant enough to generate electricity at current consumption rates for about 230 years. With improved reactor technology, recycling of spent fuel, and the use of alternate fissile material, this can be extended considerably.
While nuclear fission reactions themselves produce heat without end, they rely on finite and scarce fissile isotopes like uranium-235 and plutonium-239. Nuclear fuel efficiency can be improved, but physical limits remain on the amount of energy extracted from a given mass of fuel. This contrasts with renewable energy sources like solar and wind which are powered by endless flows of light and air.
Nuclear energy does provide exceptionally high power density and reliability not matched by other carbon-free energy sources. But nuclear is still limited by fuel supplies, metallurgy, and accumulation of nuclear waste. While not endless, uranium reserves and efficiency should allow nuclear generation to continue for centuries if utilized wisely, and could provide valuable time to transition global energy production to truly inexhaustible renewables.
