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February 26, 2020

Author: Masaharu Tsubokura

Editors: Akihiko Ozaki M.D., Yuki Senoo

157. Control rods play an important role as a brake at nuclear reactors

 Radioactive uranium produces a chain fission reaction when a neutron collides with it. Nuclear power plants generate electricity by turning a turbine with water vapor, which is obtained from heating the water using the energy released from the nuclear fission reaction of uranium 235.

 This chain reaction can take place in the presence of neutrons. In nuclear reactors, there are many neutrons produced by nuclear fission. The larger the number of neutrons, the larger the chain of fission reaction, and vice versa. Moreover, when the number of neutrons decreases, the chain reaction will eventually stop.

 To carry out the fusion reaction continuously, nuclear reactors have “control rods” whose function is to keep the number of neutrons at a constant level by absorbing them. These control rods function like a brake, which gradually decelerates the car when th...

February 25, 2020

Author: Masaharu Tsubokura

Editors: Akihiko Ozaki M.D., Yuki Senoo

155. The nuclear fusion reaction produces solar heat

 All materials that exist in the world are composed of small, invisible particles called protons, neutrons, and electrons. The numbers behind radioactive substances, as shown in cesium 134 and 137, each indicate the sum of the protons and neutrons. The nature of the substance varies depending on the balance of these numbers of particles.

 When a neutron collides with radioactive uranium 235, it causes the 235 particles of neutrons and protons to split and release energy. A fission of uranium also results in the production of a new neutron, which will then collide with another radioactive uranium and produce a new fusion reaction and more energy. Radioactive uranium produces this chain reaction when predetermined conditions are met, and the nuclear power plants and nuclear bombs operate based on this principle of nuclear fission.

 On the other hand, when light nuclei with s...

February 17, 2020

Author: Masaharu Tsubokura

Editors: Akihiko Ozaki M.D., Yuki Senoo

153. There are dozens of types of cesium

 All materials are composed of small particles called protons, neutrons, and electrons. The number after the name of radioactive substances, as in cesium 134 and 137, indicates the sum of protons and neutrons. The nature of a substance varies depending on the balance of these numbers of particles. Radioactive substances have unbalanced numbers of particles, and they emit excessive protons, neutrons, electrons, and energy to stabilize themselves. These emitted substances are called radiation.

 Furthermore, names of radioactive substances, such as cesium and uranium, are determined by the number of protons contained in their cores. That is to say, the substance named cesium always contains 55 protons.

 There are several types of cesium containing various numbers of neutrons. For example, when a cesium core contains 60 or 90 neutrons, those substances are called cesium 115 and 145, re...

February 16, 2020

Author: Masaharu Tsubokura

Editors: Akihiko Ozaki M.D., Yuki Senoo

151. Radioactive uranium and plutonium could be used as ingredients for nuclear weapons

When radioactive uranium 235, which accounts for less than 1% of natural uranium, collides with a neutron, radioactive uranium becomes unbalanced and split, which results in a release of heat. Furthermore, fission of uranium also results in the production of a new neutron, which will then collide with more radioactive uranium and produce another fusion reaction and more heat.

 Radioactive uranium produces this chain reaction when predetermined conditions are met. At a nuclear power plant, this chain reaction is gradually carried out in sealed containers to produce heat and results in the production of plutonium.

 There are also several forms of plutonium produced by nuclear reactors, but along with uranium 235, plutonium 239 is particularly prone to fission.

 The fuel utilized in nuclear power generation is approximately 3-5% concentrated...

February 5, 2020

Author: Masaharu Tsubokura

Editors: Akihiko Ozaki M.D., Yuki Senoo

149. Generation of heat by a fusion reaction of radioactive uranium

In the previous article, we explained that nuclear power plants generate electricity by turning a turbine using water vapor, which is obtained by heating water with the energy released from nuclear fusion. Furthermore, we explained that radioactive uranium is used as fuel for this nuclear fission reaction.

When a neutron collides with a radioactive uranium atom, the radioactive uranium atom becomes unbalanced and splits, resulting in a release of heat energy. The important thing is that the fission of uranium will also result in the production of a new neutron, which will then collide with another radioactive uranium atom and lead to a new fusion reaction. Radioactive uranium has the characteristics to produce a chain reaction when predetermined conditions are met as this cycle repeats.

This radioactive uranium accounts for a little less than 1% of the total...

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