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Fukushima Daiichi Nuclear Disaster Facts, Timeline, and its Aftereffects

Fukushima Daiichi Nuclear Disaster Facts, Timeline, and its Aftereffects
One of the worst nuclear accidents, the Fukushima Daiichi disaster is regarded as the largest one in this category that took place in the current century. It occurred due to a chain of events comprising an underwater earthquake and a tsunami, which affected the nuclear site located near the coastline.
Gaurav Athavale
Last Updated: Mar 26, 2018
Did You Know?
Ironically, for a nuclear disaster of this scale, there were no direct fatalities. But, at least 16,000 people died due to the effects of the undersea earthquake and resulting tsunami, which affected the eastern coastal regions. Also, more than 1,500 people died during evacuation procedures, as the housing conditions were inappropriate, and numerous hospitals and medical centers were closed.
On 11th March 2011, an earthquake struck the Tohoku Pacific coastline, which had a magnitude of 9.0 on the Richter Scale. This caused a tsunami, producing waves more than 40 meters in height, which immensely affected the Honshu region. The waves hit the nuclear plant, damaging three nuclear reactors, which caused the release of a large amount of radioactive material into the atmosphere and surrounding coastal areas. It is said that after the Chernobyl nuclear disaster of 1986, Fukushima is the largest one to have occurred.

The accident happened on such a big scale that it is rated at Level 7 of the International Nuclear Event Scale (INES), according to the severity of the incident. Apart from seawater contamination by radioactive substances, a radioactive fallout in the atmosphere is also one of the largest effects of this disaster. Further research into the matter proved that the nuclear plant disaster was more or less artificial in nature, and if proper precautions were taken during its construction, then the entire would have had withstood the effects of the tsunami and earthquake.
What Caused the Fukushima Disaster?
This disaster could have been prevented if proper assessment of any foreseeable events was done prior to the construction of the nuclear plant. Thus, the incident was mainly caused partly due to natural reasons, which started a series of events, which in turn directly affected the nuclear reactors. According to several reports, tsunami warnings were given at least a decade before, but these warnings were not believed before and safety was compromised. The Tohoku undersea mega-thrust earthquake and resultant tsunami can be called the primary cause for the Fukushima nuclear disaster. In the plant, three out of six reactors exploded when hydrogen gas started forming inside the chambers. The interior of the reactor unit chambers is mostly made up of zirconium alloy or zircaloy, which is non-reactive at a temperature of about 550°F.

In this incident, due to the effects of the earthquake and tsunami, the waves breached the perimeter walls and struck directly on the structures that housed the reactors. Before this, the reactor systems automatically shut down after the seismic waves reached the nuclear power plant region, and cooling systems started simultaneously to prevent reactor rod meltdown. Water flooded the lower floors and entered the diesel generators that supplied power to the cooling systems. The generators stopped working, and immediately the emergency systems were switched on. But, their batteries died after a day or so, and hence the original cooling systems became entirely defunct. Nuclear reactions started, and the temperatures in units 1, 2, and 3 increased above 2000°F, thus leading the alloy to react with water and produce hydrogen gas along with tremendous increase in pressure and heat. The reaction was accelerated because of increase in temperature which acted as a catalyst, ultimately resulting in large explosions.
Long-term Effects
A report by WHO in 2013 predicts chances of children developing thyroid problems may increase by at least 70%, and there might be a 5-7% chance of people developing different cancer types. Just after the accident, a state of emergency was declared by Japan, as levels of nuclear radiation inside the plant and in the surrounding areas were several times higher. The immediate releases were that of radioactive iodine, cesium, and strontium, and they were detected in the atmosphere, water, as well as soil at levels higher than normal. Increased percentage of these elements was also found in food products like beef and fish, and hence fishing was immediately banned in the surrounding areas.

Contrary to previous beliefs, the people living in the nuclear plant surroundings were exposed to very little radiation. According to studies, more than any physical injuries or radiation related severe poisoning, the majority deaths occurred during evacuation of people was due to psychological effects caused while experiencing such situations. In this case, severe anxiety, mental depression, frustration, and development of radiation sickness phobia probably lead to the death of more than 1,000 people.

In terms of release of radioactive substances, about 530,000 terabecquerels or Tbq of iodine and cesium isotopes were released till 2012, considering land, sea water, and the atmosphere. Few reports also indicated that more than 120 billion Gbq (gigabecquerels) of plutonium and neptunium isotopes were released, which are far more toxic than the other radioactive isotopes. If compared to the Chernobyl disaster, then the long term effects of Fukushima incident have an intensity of only 10% as that of the former one.

Aside from exposure effects, numerous political effects took place, wherein several protests were undertaken after the incident, which were against the increasing use of atomic energy, as well as to reconsider the set up of all nuclear plants. Various anti-nuclear demonstrations in Asia, Europe, and other parts of the world were organized. This incident also had a somewhat negative effect on the economy, wherein companies operating under nuclear power suffered huge losses, while those dependent on or supplying power through conventional energy sources gained a lot in the stock market.

Thus, no severe long term effects have been seen due to exposure, emission, and leakage of the radioactive substances till present, but increase in levels of the same were surely detected. Though this did affect the wildlife and marine life near the nuclear plants, the severity was quite less, and is expected to decrease slowly.
Investigation Committees
A couple of investigation committees were set up after the disaster to make reports and conclusions based on how the disaster events unfolded. The National Diet of Japan Fukushima Nuclear Accident Independent Investigation Commission (NAIIC) and The Investigation Committee on the Accident at the Fukushima Nuclear Power Stations (ICANPS) are these organizations.