Terrors of molten nuclear fuel

Fuel rods in Japanese nuclear reactors damaged by earthquakes and tsunamis are in danger of being completely melted and causing unintended consequences.

After successive explosions and fires occurred in four of the six nuclear reactors of the Fukushima 1 nuclear power plant, officials and Japanese nuclear experts said they did not rule out the possibility. a nuclear fusion at this plant.

So why does re-melting nuclear fuel potentially cause disaster? Below is an explanation of American nuclear experts.

Location of Fukushima nuclear power plant No. 1 (Daiichi) and No. 2 (Daini) of Japan

The basic and most important component of any nuclear plant is nuclear fuel. People take advantage of the fission process to create huge amounts of heat to boil steam generators running generators.

The main fuel used in nuclear power plants is uranium fuel rods. However, one must control the nuclear reaction to produce a sufficient heat to boil water and maintain a continuous reaction. For this purpose, the control rods contain materials that absorb neutrons such as Bo or Cadmium to control the fission process by neutrons that are bombardment agents that cause nuclear reactions.

The reactor structure is used at Japan's No.1 Fukushima nuclear power plant

The more the control rods were submerged deep into the area containing nuclear fuel, the slower the fission reaction was. However, these nuclear fuel rods still produce thermal energy, even when the control rods work normally, requiring a cooling system to maintain the temperature.

When the cooling system malfunctioned as in the case of reactors at Japan's No. 1 Fukushima nuclear power plant, the heat of the fuel rods caused the water in the boiler to dry up. If the fuel rods are exposed and the process lasts, they can eventually melt.

In the case of complete melting, the nuclear fuel may be small to the floor of the reactor. If the reactor shell structure is not sustainable enough there is a risk that the fuel with extremely dangerous radiation can spread directly to the outside environment and can cause devastating consequences.

Diagram of reactor used at Fukushima No.1 of Japan. Fuel rods (red)
may melt when not cooled in time

To visualize the damage, American scientists took the example of an explosion at the Chernobyl nuclear power plant, Ukraine in 1986. After the explosion, a cloud of radioactive dust from the factory spread out hundreds of kilometers, already causes many cases of death from cancer and birth defects in children. The high level of radiation also caused many towns around Chernobyl to become "dead", uninhabited until today.

People can also be exposed to harmful radiation through contaminated food and water. A recent UN study estimates that the Chernobyl disaster has caused 6,000 cases of thyroid cancer in children, mostly through radioactive milk.

After the Chernobyl disaster, a large area around the plant became "dead" land.

Currently, Japan only leaves 50 " suicide " workers carrying out seawater pumping, which is treated with boron to find ways to cool the core of overheating nuclear reactors at both Fukushima nuclear power plants. . If successful, Japan will extinguish completely and at the same time destroy these reactors.

After the reactors were placed under control, the fuel rods would be buried with " concrete coffins " to prevent radiation from leaking out. However, the latest information shows that the plan to use helicopters to pour seawater to cool Japanese reactors is likely to be broken.