What went wrong with Fukushima?

08/04/16

“What exactly took place with the fukushima reactor?”

 

Many people still remember the events of March 11th, 2011. On that day, an earthquake and a tsunami both with an insurmountable amount of force hit Japan, causing truly catastrophic damage. What was particularly hit were the Nuclear reactors in Fukushima, causing a great dispersal of radiation into the surrounding region

Let’s start with the basics. The reactors in Fukushima use both plutonium and uranium as fuel. These atoms are so large that they can easily become unstable. If a neutron hits them then they are likely to collapse. When fission occurs, these atoms release at least two neutrons, which  cause a butterfly effect know as a chain reaction if those neutrons hit more atoms, causing much energy to be created which ends up as heat. Fukushima use water as a coolant to form steam, which passes through a moisture separator to power a large turbine to create electrical energy.

Usually, reactors have a shutdown safety feature, in which a control rod slams into the fission reactor, stopping the fission process. However, since the isotopes are still in the process of decaying, so the “decay heat” needs to be removed so a meltdown does not ensue. Usually, this is accomplished by a cooling pump. However, this cooling pump often requires energy, so it usually takes it from the grid or two backup diesel generators.

Since radiation is still being generated, a three-layer security system is often put into place. This protection system includes fuel cadding (which uses a thin layer of a zirconium alloy to surround the fuel rod), the reactor vessel (a thick steel vessel that contains the fuel rods and a high-pressure coolant) and the containment structure (a thick shell of reinforced concrete). And since pressure from the water reactor often rises with the water temperature level, the vessel has safety valves that are designed to vent pressure (usually in the form of steam or radioactive water).

What happened in Fukushima went as follows; The earthquake caused massive tremors, which caused the fail-safety features to activate. However, the connection to the grid was knocked out by the earthquakes, and the tidal waves destroyed the diesel engines. This in turn caused a heat buildup, which in turn lead to a complete meltdown for three of the reactors.

Whatever has happened, the people lost in Fukushima will always be in our hearts, and we must strive constantly to make sure that such a calamity does not happen again. After reading, this, try to find a way to help the victims of Fukushima

• Chemistry
• Engineering
• Physics