Fukushima-1: the accident and its consequences

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

The accident at Fukushima-1 was caused by an earthquake and the tsunami that followed. The station itself had a margin of safety and would have withstood one of the elemental actions.

The catastrophe was caused by the fact that two natural disasters hit the nuclear power plant at once. The earthquake cut off the power supply to the station, immediately after that, emergency generators turned on, but they also did not work for a long time due to the tsunami.

Causes of the accident

The Fukushima-1 nuclear power plant was built in the 70s of the last century and at the time of the accident it was simply obsolete. The nuclear power plant project did not include accident management facilities that were outside the project.

And if the station survived the earthquake, then the tsunami, as mentioned above, left the nuclear power plant without power.

Before the accident, three power units were operating, and they were left without cooling, as a result - the coolant level decreased, but the pressure that steam began to create, on the contrary, began to rise.

The development of the disaster began with the first power unit. So that the reactor would not be damaged due to high pressure, it was decided to dump the steam into the containment. But her pressure quickly increased as well.

Now, to save her, they began to dump steam directly into the atmosphere. The containment was saved, but hydrogen, which was formed due to the exposure of the fuel, leaked into the lining of the reactor compartment.

All this led to an explosion at the first power unit. It happened the day after the March 12th earthquake. The explosion partially destroyed the concrete structures, but the reactor vessel was not damaged.

Development of events

After the explosion at the power unit, the level of radiation increased greatly, but after a few hours it fell. Samples were taken from the territory of the Fukushima-1 nuclear power plant, and studies showed the presence of cesium. This meant that the tightness of the reactor was broken.

Sea water was pumped in to cool the reactor. The next day, it turned out that the emergency cooling system in the third block was damaged. And there was a suspicion that the fuel elements were partially exposed, and again a hydrogen explosion could occur.

Began to release steam from the containment and pump in sea water. But this did not help, and the explosion occurred on March 14. However, the reactor vessel was not damaged.

Continue work to restore electricity to the first and second blocks. We also continued pumping water to the first and third blocks.

On the same day, the emergency cooling system at the second power unit also failed. We started pumping sea water for cooling. But suddenly the valve for dumping steam broke, and it became impossible to pump water.

But that's the troubleFukushima-1 is not over. The explosion at the second power unit still happened on the morning of March 15. The storage of nuclear fuel at the fourth power unit immediately exploded. The fire was extinguished only two hours later.

On the morning of March 17, they began to dump sea water from helicopters into the pools of blocks 3 and 4. After the restoration of the diesel station at the sixth block, it became possible to pump water using pumps.

Crash response

In order for the regular systems to start functioning, it was necessary to restore the power supply. And to restore it, it was necessary to pump out water from the flooded turbine rooms.

Everything was complicated by the fact that the level of radiation in the water was very high. The question arose: where to pump this water. To do this, we decided to build a treatment plant.

The company that owns Fukushima 1 said it would have to dump 10,000 tons of low-radiation water into the sea to free up the high-radioactive water tanks from the first three nuclear power plants.

According to the plan, the complete elimination of the consequences will take about forty years. The reactors of the nuclear power plant were shut down and the extraction of spent nuclear fuel from the pools began. Later, the complete dismantling of the reactors of the Fukushima-1 nuclear power plant is expected.

Consequences of the accident

As a result of all the events, a radiation leak occurred. The government had to evacuate the population from the 20-kilometer zone around the nuclear power plant. Those who lived 30 kilometers from the Fukushima-1 nuclear power plant were strongly recommended to evacuate.

Japan,Fukushima-1 and its surroundings are contaminated with radioactive elements. They were also found in drinking water, milk and some other products. The norm was below the permissible, but for reinsurance, their use was temporarily banned.

Radiation detected in sea water and soil. Background radiation has increased in some regions of the planet.

In addition to environmental pollution, there are financial losses. TERCO is obliged to pay compensation to the victims of the accident.

Fukushima-1 today

Today, liquidation work continues at the nuclear power plant. In May 2015, radioactive water leaked. The purification of the water extracted from the blocks also continues.

This is one of the main problems. There is a lot of highly radioactive water, and in the process of cooling the reactors, it becomes even more. It is pumped into special underground storage facilities, gradually being cleaned.