America faces two critical challenges this century. The first is responding to the uncertainty that the abnormally high and rising atmospheric carbon dioxide (CO2) level will have detrimental environmental consequences for human civilization. The second is replacing the diminishing U.S. technically recoverable fossil fuel endowment with new non-fossil fuel energy sources. Fission nuclear energy is one of the three primary non-fossil fuel terrestrial energy sources that could possibly replace fossil fuels. However, it is not practical to scale up fission nuclear energy to replace fossil fuels.
“Understanding Why Nuclear Power Cannot Replace Fossil Fuels” is the third of an Energy & Environmental Security Series of videos published on the Spacefaring Institute’s™ YouTube® channel. These videos explain why the United States should undertake an orderly transition from fossil fuels to space-based solar energy. The video includes an introduction to space solar power and illustrations of the types of spacefaring capabilities America’s aerospace industry can now design and build to enable America to become a true commercial human spacefaring nation and undertake space solar power.
This 15-minute video addresses these topics:
- What is the scale of nuclear power needed to replace fossil fuel use in the United States?
- How does a nuclear fission power plant work?
- Is there sufficient natural uranium available to scale up nuclear power?
- Can nuclear fuel breeding be used to scale up nuclear power?
- What should America do with terrestrial nuclear power?
- What is the path forward for America to transition from fossil fuels?
The script of the video follows:
Introduction
The United States faces two important challenges this century related to our use of fossil fuels. The first arises from our substantial dependence on fossil fuels. While the United States has a technically recoverable fossil fuel endowment of about 1,500 billion barrels of oil equivalent or BOE, the fossil fuel demands by a growing U.S. population, expected to reach 500 million by 2100, will likely exhaust this endowment before 2100. This constitutes an energy security challenge that cannot be ignored. The second challenge is reining in carbon dioxide emissions from our use of fossil fuels. The abnormally high and still rising atmospheric carbon dioxide level, now 40 percent higher than what has been seen over the last 800,000 years, creates uncertainty that this may threaten human civilization. The reasonable response to these challenges is to curtail our use of fossil fuels, in an orderly manner, by switching to new sustainable energy sources. The list of potential terrestrial alternatives to replace fossil fuels is relatively short with nuclear fission energy being one of the three primary alternatives. To understand the practicality of nuclear fission energy replacing fossil fuels, this Spacefaring Institute video addresses:
- What is the scale of nuclear power needed to replace fossil fuel use in the United States?
- How does a nuclear fission power plant work?
- Is there sufficient natural uranium available to scale up nuclear power?
- Can nuclear fuel breeding be used to scale up nuclear power?
- What should America do with terrestrial nuclear power?
- And, what is the path forward for America to transition from fossil fuels?
Part A – What is the scale of nuclear energy needed to replace fossil fuel use in the United States?
In American in 2015, with a population of 320 million, fossil fuels provided about 80 percent of the energy used, meeting the needs of about 256 million Americans. About 40 percent of the total energy is used as electricity with the remaining 60 percent used as fuels. A nuclear power plant generates electricity which can be used directly and can be used to produce hydrogen fuel from water using electrolysis. A typical terrestrial nuclear power plant produces 1 billion watts or 1 gigawatt of electrical power. If used to provide both electricity and hydrogen, each 1 gigawatt plant can meet the energy needs of about 100,000 Americans. Replacing fossil fuels for 256 million Americans would take nearly 2,600 one gigawatt nuclear power plants. Meeting the energy needs of the likely 500 million Americans in 2100 would require about 4,000 one gigawatt nuclear power plants. For perspective, there are now about 100 commercial nuclear plants operating in the United States.
Part B – How does a nuclear fission power plant work?
Of the natural elements found in abundance on the Earth, only uranium is capable of fissioning to produce useful nuclear energy. The uranium atom’s nucleus is comprised of protons and neutrons. While every uranium atom has 92 protons, the number of neutrons can vary. The uranium isotope, U-235, contains 92 protons and 143 neutrons for a total of 235 subatomic particles. Of the naturally abundant isotopes, only U -235 is capable of fissioning. When a U-235 nucleus absorbs an extra neutron, it fissions, splitting into two parts. In the process, a small amount of the mass of the original nucleus converts into energy. This released nuclear energy is what powers nuclear fission power plants. In a nuclear power plant, this nuclear energy heats water to create steam which drives turbine generators to produce electricity. Because fission nuclear power plants do not burn fossil fuels or release carbon dioxide into the atmosphere, some see terrestrial nuclear power as an attractive replacement for fossil fuels.
Part C – Is there sufficient natural uranium available to scale up nuclear power?
The U-235 isotope only makes up 0.7 percent of the naturally available uranium. Almost all of the rest of the naturally available uranium is the U-238 isotope which does not fission. To fuel a conventional 1 gigawatt nuclear power plant, approximately 163 metric tonnes of uranium is needed each year according to the World Nuclear Association. A new nuclear power plant is licensed for 60 years meaning each will need a 60-year supply of uranium to operate. Each new plant will require nearly 10,000 metric tonnes of natural uranium to operate for 60 years. As of 2009, the last year reported, the identified reasonably assured and inferred United States uranium resources totaled 472,000 metric tonnes. While this sounds like a large supply, this would only supply about 48 1-GW plants for their 60-year lives. Obviously, the United States does not have sufficient uranium for the thousands of nuclear plants required to replace fossil fuels. What about obtaining uranium from other sources? For the entire world, the identified reasonably assured and inferred uranium resources total about 6.3 million metric tonnes. This is sufficient to power about 645 1-GW plants for their 60-year lives. As of 2016, the world has a total of 508 GW of nuclear power operating or under construction. Thus, the ability to significantly expand the number of nuclear power plants is limited by the availability of fuel.
Part D – Can nuclear fuel breeding be used to scale up nuclear power?
Two isotopes that do fission like U-235 can be artificially created in special nuclear reactors. This is called nuclear breeding. One is the uranium isotope, U-233, while the second is the plutonium Pu-238 isotope. Both can be used, like U-235, to power a nuclear reactor. Unfortunately, like U-235, these can also be used to produce nuclear weapons. Thus, with tens of thousands of nuclear plants needed worldwide to replace fossil fuels, breeding fuel raises serious concerns about nuclear weapon proliferation. For this reason, breeding is not a practical solution.
Part E – What should America do with terrestrial nuclear energy?
Nuclear power provides the ability to produce baseload electrical power without using fossil fuels. However, while older U.S. nuclear power plants should be replaced with newer, safer plants, the availability of natural U-235 fuel will limit how many plants can be built. Also, issues such as nuclear waste disposal, plant siting for earthquake and tsunami safety, and providing sufficient cooling water will also limit how many new U.S. plants can be built.
Part F – What is the path forward for America to transition from fossil fuels?
While a modest updating of America’s current commercial nuclear power plants is appropriate, a substantial scale up of nuclear power to replace fossil fuels is not practical. This leaves wind and ground solar energy as the two remaining terrestrial solutions to replace fossil fuels. Yet, as discussed in Understanding Why Wind and Ground Solar Energy Cannot Replace Fossil Fuels, these, also, are not practical solutions. This leaves the United States with one viable sustainable energy source – space solar power. In geostationary Earth orbit, or GEO, sunlight is available almost the entire year. Large space solar power platforms located in GEO can capture sunlight, convert this into electrical power, and transmit this almost continuously to ground receiving stations that would supply dispatched electrical power to customers and produce hydrogen fuel. Over the last two centuries, America has moved from wood to coal, and, then, to oil, natural gas, hydroelectricity, nuclear energy, and wind and ground solar energy to meet its increasing energy needs. The final step in this technological progression to space-based solar energy is now inevitable, due to serious energy and environmental security challenges that cannot be avoided. This next step will require that the United States become a true commercial human spacefaring nation tapping the energy and natural resources of the solar system, to obtain the non-fossil fuel energy our children and grandchildren will need. This bright and exciting spacefaring future – long an American dream – is now at hand.