On Thursday, ten years have passed since the earthquake off the east coast of Japan, when a tsunami struck the Fukushima nuclear power plant, causing a core to melt and a gas explosion and scattered large quantities of radioactive material as a result.
The Fukushima accident really showed that we must always be prepared for the unexpected and the unexpected. We must also never settle down and think we are ready now, said Nina Kromnier, director general of the Swedish Radiation Safety Authority. National Radiation Safety Day at the authority In February.
On March 11, 2011, three reactors were put into operation at the Daiichi Nuclear Power Plant in Fukushima. At 14.46 o’clock, the earthquake, one of the strongest earthquakes ever measured, struck its epicenter 150 km away. The power grid has been shut down, but the nuclear power plant is designed to withstand earthquakes, and cooling and safety systems can continue to operate with diesel generators and batteries.
After about 50 minutes Earthquake will tsunami. The fences that will protect the nuclear power plant are six meters high, and they have no chance against the 14-meter tidal wave. Water drowns everything and cuts off batteries, pumps and backup units.
One day after the tsunami, a gas explosion destroyed the building surrounding reactor 1. After another two days, an explosion occurred in the reactor 3. The reactor building was destroyed, along with a backup system that until then was able to continue cooling down reactor 2. The gas also leaks out and causes Another explosion in a failed reactor.
We have been simulating operations with a total loss of external electricity supply in Sweden since the 1980s. The difference here is that the battery supply was also interrupted. It really makes the situation worse. Batteries are needed, for example, for control rooms and for valve control. When you simulated accidents, you expected to be able to perform at least a few maneuvers. It didn’t work out here, says Patrick Isaacson, an investigator with the Swedish Radiation Safety Authority.
The people who lived in it The area was hit hard in a number of different ways. The earthquake and tsunami killed nearly 16,000 people, and lost 160,000 their homes. Large areas around the nuclear power plant have been evacuated and shut down. The nuclear accident also led to the disappearance of the demand for food and other agricultural products from the region, resulting in the loss of many of their livelihoods.
The evacuation of most of the area has continued for several years, but at the beginning of last year only about a third of those evicted have returned. There could be many reasons for this, such as a lack of work, or that you have already established yourself elsewhere or are concerned about radiation and radioactive materials.
Fukushima accident and Chernobyl crash 1986 is the two worst nuclear accidents the world has seen. Both are classified as Level 7 High, a major accident, on the so-called INAS scale. But the consequences in terms of deaths, radiation doses, and emissions of radioactive material are very different. In Chernobyl, 30 people died from radiation injuries within two weeks, and there are several thousand people at higher risk of cancer. In Fukushima, two people drowned while examining the damage, but no acute radiation damage was detected in anyone working at the nuclear power plant or had been in the vicinity.
The United Nations agency UNSCEAR, the United Nations Scientific Committee on the Effects of Atomic Radiation, also could not see any health effects of the radiation from the nuclear accident on residents of the area, according to New report. Cancer cases have not increased and there are no birth defects, miscarriages, or low birth weight that could be linked to radiation. Japanese authorities were concerned about the increase in thyroid cancer rates in children because it was one of the clearest consequences of the Chernobyl accident, in which about 6,000 children were injured. They found 200 children near Fukushima suspected of having thyroid changes after the accident, but according to UNSCEAR, this was due to more comprehensive examinations rather than radiation damage. The fall was discovered near Fukushima during the first three years, while the increase near Chernobyl did not begin until five years after the accident.
But the accident led to several other health effects, such as an increased incidence of cardiovascular disease and an increase in mental illness in the evacuees, according to the UNSCEAR report.
Japan is working It is difficult to take care of destroyed reactors, and to restore the area around a nuclear power plant. Among other things, layers of soil containing very high levels of radioactive materials were scraped off.
It’s a huge amount of work to uncover, and they have very high ambitions. It will take many decades, says Patrick Isaacson.
If a similar accident occurred at a Swedish nuclear power plant, it is likely that the same amount of radioactivity would not have leaked due to our high safety demands in building the reactors. The nuclear meltdown at the Three Mile Island Nuclear Power Plant outside Harrisburg, Pennsylvania, in March 1979, had greater consequences for nuclear safety in Sweden than in most other countries.
– Before this accident, there were no serious incidents on the wallpaper. Patrick Isaacson says the poor workers did not have conditions to deal with what happened, made mistakes and created the accident themselves.
The consequences for people And nature was almost non-existent, as all radioactive materials were kept inside the reactor container, and no person was exposed to measurable health effects radiation doses. But the controversy that followed the accident outside Harrisburg led Sweden to prepare for very dangerous accidents, with evacuation plans, alarm systems and iodine tablets for residents near nuclear power plants and requirements for filters that capture nearly all radioactive materials in the event of a malfunction. .
One of the requirements that Sweden imposes on female candidates is that there should be no deaths. This did not happen in Fukushima, but there is also a requirement that there should not be long-term soil pollution as well. The challenge that I see as my job is to make sure that in the event of a serious accident the emissions have to pass through the filter. And Patrick Isaacson says there are good conditions for them to do so.
The likelihood of a tsunami in Sweden is very low, but our nuclear power plants could be affected by other natural phenomena, such as ice storms or rising sea levels.
The most important lesson from Fukushima is not to take anything for granted. Patrick Isaacson says: To be questioning and reassessing constantly, and not to feel good about ourselves, and I think we managed to manage that safely.
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