Hello everyone.
I am in charge of public relations for Kyoto Fusioneering.
In December of this year, the “Vacuum2025 Vacuum Exhibition” with the theme of vacuum engineering was held at Tokyo Big Sight, bringing together companies and organizations dealing with vacuum technology.
In this 10th installment of the Gori Bun series, we will start by asking, “What is a vacuum?” and will explain the importance of vacuum technology in fusion energy, the role of vacuum pumps, which are one of the essential devices for vacuum technology, and our activities in joint development with Japanese manufacturing companies.
What do you think, what is a vacuum?
When you hear the word “vacuum,” you may think of “a state in which there is no air at all” because of images such as vacuum packs, but this is actually not the case.
According to JIS (Japanese Industrial Standards), “vacuum” is defined as “a state of space filled with gas at a pressure lower than normal atmospheric pressure.” In other words, if air is sucked out from inside a pipe or container using a pump, etc., and the pressure becomes lower than atmospheric pressure, even if some air or gas remains, it can be called a “vacuum.”
For your reference:https://www.jstage.jst.go.jp/article/vss/65/8/65_20180914/_pdf
Vacuum technology is also used around the world!
Vacuum technology is also widely used in my daily life.
An easy-to-understand use is to prevent food from losing its freshness. For example, in the case of coffee beans, by removing the air from the bag containing the beans and making it difficult for them to come into contact with oxygen, the beans can be prevented from oxidizing and their aroma and flavor can be recognized.
Vacuum technology is also used in thermos flasks (tumblers).
Furthermore, the mechanism by which the drink is sucked up through the straw is also based on vacuum. When you suck on a straw, the air pressure inside the straw is reduced, creating a pressure difference with the atmospheric pressure outside the straw, which forces the drink upwards.
Utilizing vacuum technology and pumps that can be used with Fusion Energy
Fusion energy plants are also described as “huge and complex vacuum systems” and do not require vacuum technology.
The answer is that vacuum technology is used to create an environment for nuclear fusion reactions.
In order to cause a nuclear fusion reaction, it is necessary to convert hydrogen isotopes (deuterium and tritium), which serve as fuel, into “plasma,” the fourth state after solid, liquid, and gas. Plasma, as shown in the diagram below, is a state in which the particles are separated into electrons and atomic nuclei, and the electrically charged particles move around freely.
In order to continue converting fuel into plasma, it is necessary to raise the temperature of the furnace to hundreds of millions of degrees, and this is where vacuum technology comes into play.
For example, in the “magnetic confinement method,” which uses all kinds of magnetic fields to generate a magnetic field, confine the plasma within it, and match the fuels well, the balance of temperature, vacuum, and magnetic field is important in order to maintain the plasma state very well and increase and maintain the efficiency of the fusion reaction.
Therefore, a vacuum pump, which emphasizes vacuum conditions, is an important device for causing nuclear fusion reactions.
* Regarding the confinement method,herePlease see Goribun’s blog.
Vacuum technology is also used in the John Fuel Cycle System, which exhausts fuel in a furnace, removes impurities, and then inputs it again as fuel.
Hydrogen is the first and shortest light element on the chemical periodic table, so it has the characteristic of passing through materials such as metals. However, since tritium, the fuel, is a radioactive substance, its penetration must be avoided from a safety perspective.
*For information on the Fusion Fuel Cycle SystemherePlease take a look at
What are the characteristics of the pumps used in Fusion Energy Plants?
Pumps are essential for creating a vacuum, but in order to use a fusion energy plant, they must be adapted to special conditions.
First, it must have high durability against the tritium gas fuel. Tritium, a radioactive substance, has the property of reacting with organic materials such as rubber and resin, causing them to deteriorate.
In addition, the ability to efficiently transport even light elements is required. Fusion energy plants handle elements such as hydrogen and helium, which are light, small, and move around in space first. Therefore, the ability to transport light elements is required, and a special structure is required.
Additionally, since vacuum pumping performance may be gas dependent, it is necessary to perform performance tests to determine how efficiently the gas type of the actual plant can be transported under various gas conditions.
A pump that brings together Japan’s “manufacturing power”
We are currently developing pumps that are suitable for the environment of fusion energy plants by combining our unique know-how regarding fusion energy with the manufacturing capabilities of Japanese companies.
- Rough vacuum pump:A “roughing vacuum pump” that lowers the pressure from atmospheric pressure all at once.Mikuni Heavy IndustriesUsed when using a pump that cannot function at atmospheric pressure due to high pressure.
- turbo molecular pump:After lowering the pressure with a rough vacuum pump, we are developing a “turbo molecular pump” that rotates at high speed and blows out gas in order to create a high vacuum.Shimadzu Corporationand developed a prototype.
- Metal bellows pump: This pump uses accordion-like metal bellows to expand and contract to adjust air pressure and control gas flow. By making it “full metal” without using any rubber or oil, we have achieved durability against tritium.
These pumps, which we are currently developing in Japan, will be tested using tritium at UNITY-2, an integrated tritium fuel cycle testing facility currently under construction in Canada.
The vacuum technology we introduced this time is one such technology, but in fact, many of the technologies that are widely used in everyday life are also used at John Energy.
We will continue to introduce the elemental technologies necessary to realize fusion energy and the development status of the fusion fuel cycle system on our blog, so please continue to pay attention.
Kyoto Fusioneering is looking for members who will work with us to open up the future of energy.
Recruitment detailsThis pageWe also disseminate information on our official SNS.
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