Can human beings put the ultimate energy source "fusion energy" into practical use?

On the Earth where population growth continues, how to secure energy such as electric power necessary for human life becomes an important issue. Although thermal power generation and nuclear power generation are mainly used for generating electricity, research that is being studied as future power generation technology is based on "Nuclear fusion power generation"is. What is the fusion energy technology that has seawater as a fuel to generate energy and has very little impact on the environment and what challenges do you have?Kurzgesagt - In a NutshellThe movies are summarized.

Fusion Energy Explained - Future or Failure - YouTube


What we call "currency" of the universe is energy


With energy, our house is brightly lit up, we can raise food and gain power to move the computer


There are several ways to get power from energy. The typical one is thermal power generation that burns fossil fuel, nuclear power generation that uses nuclear fission, and solar power generation that generates from sunlight ......


All these have drawbacks. Thermal power plants emit dirty air, and nuclear power plants produce high-level nuclear waste. Also, solar power generation can not generate electricity without the sun, and there is currently no mechanism to store electricity for a cloudy day.


However, there are things with practically infinite energy. That is "sun".


In order to acquire this infinite energy, can mankind create the sun on the earth?


The sun is shining because "nuclear fusion reaction" is occurring within it.


At the center of the sun, which has a very strong gravity, high pressure is applied and it is very high temperature. Therefore, the atoms constituting the substance ...


The plasma state is separated from the nucleus (red) and electron (blue).


At the center of the sun, which is in the plasma state, nuclei and electrons are freely flying around. Because nuclei have a positive charge, they normally repel each other.


In order to surpass this repulsion, nuclei need to collide at a very high speed.


"Very high speed" here means "very high temperature". In the core of the actual sun "core", the temperature has reached 14 million to 15 million Kelvin (about 14 million to 15 million degrees Celsius).


The stars such as the sun are very large in volume and the internal pressure is extremely high.


In cores where high temperatures are generated due to pressure, nuclei fuse together and new substances are produced ......


At that time, very large energy is released. This energy is heat, sunlight, electromagnetic waves and so on.


And this energy release is the "fusion reactor" scientists are conducting research as "new generation generation technology".


However, it is impossible to reproduce nuclear fusion with the same mechanism as the sun on a smaller earth than the sun. Therefore, human beings need to create an environment similar to the sun by using another "smart" way.


In order to make the temperature of the plasma extremely high and bring the state of nuclear fusion into existence, scientists have largely devised two methods.


One of them is to generate a strong line of magnetic force to confine plasma "Magnetic field confinement methodIt is what is called.


The representative one is the International Thermonuclear Experimental Reactor "ITER (Eater)" to be constructed in France. ITER uses a superconducting coil cooled by liquid helium to generate a strong magnetic field and confine the plasma in it.


In this system, a superconducting coil extremely close to absolute zero is used, which produces the plasma of the highest temperature in the universe which humans can know.


Research on ITER is being promoted jointly by Europe, Japan, Russia, America, Korea, China, India. Details can be seen in the following site in detail.

International thermonuclear fusion experiment experimental furnace ITER website


Another way is to cause nuclear fusion by irradiating a fuel with a powerful laser "Inertial confinement methodWhat is called.


At the same time that plasma is generated by irradiating the laser surface to the surface of the fuel, the plasma to be expanded is pressed down by the power of the laser and crushed into the insideImplosion. This mechanism is to fuse light elements inside the fuel by the high temperature and pressure generated at this time.


In order to cause nuclear fusion with the inertial confinement system, it is necessary to irradiate the fuel with extremely high precision from every direction from a very powerful laser.


Research on nuclear fusion by this method is being conducted all over the world,National Ignition Facility(NIF: National Ignition Facility), research is being conducted in Japan as well.


In addition to this, research on nuclear fusion by several methods is underway all over the world, but these are all in the research stage.


It is a nuclear fusion reactor that is being studied to generate energy, but most of existing fusion reactors do not produce energy that exceeds the energy (= electricity) necessary to operate. In other words, even if you squeeze by throwing fuel (fruit) as a material into the mixer ......


The result (= juice) obtained is still in a state with little.


Nuclear fusion has been researched since around the 1920s, but it has not yet reached the point where it is commercially feasible. Furthermore, there is a negative view about its practicality. A huge amount of trillion yen is required for the construction of the facility, and it is unclear whether this fee can be collected.


However, if a fusion reactor is realized, there is no efficient energy source so far. In a nuclear fusion reactor where sea water becomes fuel, you can produce the same energy as a barrel (about 160 liters) of oil from a glass of water. Furthermore, because there is no emission of carbon dioxide or the like, it is a great merit that there is little impact on the environment.


This is because fuels used in fusion are made of hydrogen and helium. And this hydrogen can be produced from seawater.


Nonetheless, it does not matter if it is hydrogen. Nuclear fusion reactions require stable hydrogen isotope, dual hydrogen (deuterium) and tritium (tritium).


Among them, deuterium is contained in sea water in large amounts, but tritium is a little troublesome.


Tritium has radioactivity, its half-life is 12.3 years. Therefore, the influence by radiation exists.


Also, tritium is used mostly for nuclear bombs. Therefore, tritium is a very expensive material.


Thus, instead of troublesome tritium, it is the helium isotopeHelium 3is.


However, helium 3 is as rare as tritium, so it is not easy to secure a sufficient amount on the earth.


What is drawing attention there is the "moon" circling the earth.


On the surface of the moon, it is believed that helium 3 is produced and present as a result of receiving solar wind for hundreds of millions of years.


Therefore, the idea of ​​constructing a factory that produces helium 3 by collecting the moon soil and creating a mechanism to deliver it to the earth with a rocket is also made.


There are also voices that worry about another. Nuclear fusion is, as it were, like making a mini-sun on earth. Therefore, although worry is also occurring that a large explosion will occur due to abrupt release of a large amount of energy ......


In fact, nuclear fusion power plants are considered to be safer than any other power generation method.


Nuclear fusion reactors have quite different characteristics from nuclear power plants that use energy from nuclear fission. In the case of a nuclear fission reactor, if proper control is not performed, it will lead to catastrophic damage ... ...


In nuclear fusion reactors, "plasma confinement" by magnetic force and laser is being performed. Even if problems occur in control, when plasma confinement no longer takes place ...


The plasma automatically disappears and the pressure and temperature necessary for fusion are lost. Therefore, nuclear fusion does not fall into a runaway situation.


There is also concern about the environmental impact caused by release of radioactive tritium.


Tritium combines with oxygen and turns into water with radioactivity. It is concerned that damage to the environment will be hurt if this water flows out to the ocean etc ... ...


The amount of tritium in the first place is extremely small, so it is believed that there is virtually no effect on the environment.


As you can see, nuclear fusion produces a lot of energy from less fuel and is more gentle on the earth, so you can see what is expected.


However, the primary problem is where you do not know how much it will cost to realize. In other words, although I do not know whether or not it will cost you trillions of yen, real gambling is an unprecedented gambling in the history that you can gain great benefits.


So, if you are putting the same money, investing in already established existing technology may produce better results.


In some cases, it is conceivable that a large amount of budget is spent, leaving legacy that is not usable.


However, if the result gets infinite energy safely, the merit that human beings can obtain is likely to be infinite. Whether mankind challenges the gambling "nuclear fusion energy" in this way is likely to be a theme to be considered over time in the future.