Image by Burghard Mohren from Pixabay.
It is undeniable that bitcoin consumes a lot of power as miners verify transactions using proof of work. According to the Cambridge bitcoin Electricity Consumption Index, the network is currently consuming 14.93 gigawatts of power (cbeci.org). That is 139.15 terawatt hours per year, more than the energy consumption of Norway and Argentina, among other countries (BBC). One cannot argue that bitcoin guzzles electricity. And something needs to be done about it. Bitcoin may not contribute as much CO2 to the atmosphere as gasoline cars and many other activities, but it is significant. 36.95 megatons are put into the air by the currency every year according to CNBC.
This is not good. We totally agree with those who say that this is a problem. Many miners are moving to renewable power, which is good, but a lot are still relying on cheap coal energy. But it is not a problem that is unique to this cryptocurrency. The whole world is putting billions of tonnes of the greenhouse gas into our only atmosphere every year. Something needs to be done. I believe that nuclear power is a solution to the world’s need for clean energy. It is our best shot at placating our insatiable need for energy. Nuclear fusion has the potential to supply virtually limitless energy from seawater if we can only figure out how to harness it. And nuclear fission, if it can dispel its bad rap sheet, has the potential to give us energy in a safe matter. It is important that we understand this technology if we are to consider using it in the future to combat the imminent threat of climate change. So read on, and learn about the wonders of atomic electricity generation.
The Structure of an Atom
Atoms have three parts:
- Neutrons are neutrally charged particles
- Protons are positively charged
- Electrons are negative
Neutrons and protons are in the nucleus, and the electrons orbit around. The number of protons that are in the atom, specifically the nucleus, determines which element the atom is. The number of neutrons is similar to the number of protons. The two balance each other out.
Different isotopes of an element have different numbers of neutrons in the nucleus. So if one nucleus of helium had one neutron, and another had two, they would be different isotopes of helium.
There are three different types of Nuclear Reactions.
- Radioactive Decay
- Nuclear Fission
- Nuclear Fusion
- Radioactive decay occurs when a nucleus is unstable.
- In nature, extremely heavy atoms undergo radioactive decay because they are unstable. An example is Uranium.
- When there is a major difference between the number of protons and the number of neutrons in an atom, it also is unstable.
- When atoms undergo radioactive decay they usually turn into another element and release radiation (particles or photons).
- Radioactive decay is what makes things like uranium and nuclear waste radioactive and dangerous to handle.
- Nuclear Fission is when a heavy atom splits into two lighter atoms. When a neutron hits the nucleus of an atom like Uranium, it causes the atom to break apart.
- It is millions of times more powerful than chemical reactions.
- A heavy atom is known as “fissile” if it can be split easily. Fissile atoms can sustain chain reactions when a critical mass is present.
- Uranium 235, an isotope or type of Uranium that is found in small quantities in natural uranium, is fissile. When a neutron hits U235, it splits. This releases 2-3 neutrons, two other light atoms, and a lot of energy. Those neutrons can in turn split more atoms causing a chain reaction. A runaway fission reaction is what powers an atom bomb. Controlled chain reactions are needed for nuclear power generation.
- Ninety-nine percent of natural uranium is of the isotope 238. U238 is not fissile; it cannot sustain a chain reaction. Zero-point-seven percent of natural uranium is U235. The fuel has to be enriched to three to five percent U235 in order to sustain a chain reaction and be used for electric generation, according to World-Nuclear. This process is expensive because giant centrifuge plants are needed, and it is dangerous because the same technology can be used to make nuclear bombs.
- Fission powers modern-day nuclear power plants.
- Nuclear Fusion is when two atoms fuse together into a third element.
- When light atoms fuse they release a lot of energy, more than nuclear fission.
- The most powerful fusion reaction is when tritium (an isotope of hydrogen with two neutrons), and deuterium (hydrogen with one neutron) fuse together to form helium. This is eight times as powerful as nuclear fission.
The Downsides of Fusion
- We have not been able to build a fusion power plant that produces as much energy as is put in. We have only achieved 70 percent out.
- This is because for atoms to fuse, they need to be raised to around 100 million degrees Celcius to break their electrostatic repulsion and fuse. Getting to 100 million degrees is difficult. But once the fuel is at 100 million degrees and lots of fusion starts, the reaction can continue going on its own, with the heat from the fusion reactions keeping the fuel at millions of degrees. This is called ignition.
- Fusion has only produced more energy than was put in during the detonation of hydrogen bombs. Fusion fuel is compressed and heated by a fission bomb until there is a fusion chain reaction.
The Future of Fusion
- Nuclear Fusion has the ability to end climate change. Seawater contains enough of the heavy hydrogen fuel that is required to power our civilization for 6 million years.
- Fusion reactors cannot meltdown. Fuel is confined in a fusion reactor by magnetic fields and other methods. But once this confinement is switched off or is disturbed by an anomaly, the fusion fuel disperses, and the temperature drops until the reaction stops. There is also not enough fuel in the reactor at any one time for a chain-reaction-causing meltdown.
Different Approaches to Fusion
- One method of causing nuclear fusion uses magnetic fields to confine plasma into a donut shape. The plasma is then heated to fusion temperatures. This is the most promising method.
- Lasers can also be used. A five hundred trillion watt laser is pointed at a small pellet of fusion fuel and the atoms are forced to fuse.
- Another method is electric fields. Giant capacitors dump lots of electricity into small wires. This causes fusion fuel to implode and fuse.
Today’s Nuclear Power Plants
- Nuclear Power Plants today run on Nuclear Fission.
- They are usually fueled by partially enriched uranium, but sometimes Plutonium can also be used. All reactors in the US run on uranium.
- There are 58 nuclear power plants in the US, accounting for 20 percent of electricity generation.
- In the US there are boiling water reactors (BWRs) and pressurized water reactors (PWRs). There are many more PWRs.
- There are only a few major differences between PWRs and BWRs. Because of this and the prevalence of PWRs, only the design of Pressurized Water Reactors will now be discussed.
How a PWR Nuclear Reactor Works: The Core
- The nuclear reactor core is where the nuclear reactions take place.
- The core is located in a pressure vessel made of steel. The pressure is kept at over one hundred atmospheres.
- There are around 200 fuel assemblies in the core. Each assembly is a bundle of 100 zirconium fuel rods. Inside the rods are uranium fuel pellets. These pellets are what undergo fission.
- Control rods made out of boron or cadmium, which absorb neutrons, are kept inserted into the core, between the fuel assemblies. When they are withdrawn, the fission reaction starts.
- Cooling water is circulated through the core and carries away heat. This water cannot boil even though it is at over 620 degrees Fahrenheit because of the pressure. This gives the reactor its name.
Cooling and Steam Generation
- Coolant is pumped into the pressure vessel at the bottom and comes out the top 350 degrees C (600 F).
- The hot water goes into a giant machine called a steam generator. Inside, the hot coolant is pumped into many small U-shaped tubes. These tubes are inside a massive reservoir of secondary water. Heat is transferred from the water in the U tubes to the secondary water. The secondary water boils and turns to steam. The secondary water, unlike the primary, is not radioactive.
- This steam is pumped to the steam turbine.
Turbine, Electric Generator, and Condensation
- Steam is piped from the steam generator to the steam turbine. The steam turbine looks like a jet engine.
- The steam turbine blades start spinning when high-pressure steam passes through them. The turbine spins at 1500 revolutions per minute.
- The turbine central shaft is attached to an electric generator. The spinning of magnets inside the generator generates hundreds of megawatts of electricity.
- Afterward, the steam is piped into a big box with thousands of pipes running through it, called a condenser. Heat is transferred to the small pipes and the steam condenses back into water. The condensed water is pumped back to the steam generator. Meanwhile, the hot water in the small pipes is pumped to a cooling tower where it is cooled and partially evaporated. Then more water is pumped from a body of water to make up for the evaporated steam and all of the water is pumped back to the reservoir.
Putting It All Together
Here is a diagram that shows the whole system:
The Future of Fission
- Fission power plants can result in meltdowns, which is what is causing pressure for them to be shut down, but there are several designs in the works that will make power plants much safer and more advanced. These are called fourth generation reactors, and they have the potential to revolutionize this field. They will allow us to continue to use nuclear fission without fear.
- Reactors in the future could use molten sodium as coolant, increasing efficiency.
- Small reactors could be mass produced and many could be made. Their small size would prevent meltdowns. Nuscale’s small modular reactors are an example (nuscalepower.com).
- Breeder reactors could be made that make more fuel than they consume. These could power us for thousands of years.
- Fission power plants emit no CO2, so to beat climate change we must start using safer and next-generation versions of them more.
If you would like to suggest a modification, please leave a comment below. All opinions expressed in this article are purely those of the author and do not necessary reflect the views of GoldPundit.
Sources of Information:
Wood, J. (2007). Nuclear Power. London, United Kingdom: Institute of Engineering and Technology.
Seife, C. (2009). Sun in a bottle: The strange history of fusion and the science of wishful thinking. London: Penguin.
Pressurized water reactor. (2021, March 18). Retrieved March 29, 2021, from https://en.wikipedia.org/wiki/Pressurized_water_reactor#:~:text=A%20pressurized%20water%20reactor%20(PWR,of%20light%2Dwater%20nuclear%20reactor.&text=The%20heated%2C%20high%20pressure%20water,which%20spin%20an%20electric%20generator.