Fukushima Daiichi Nuclear Power Plant disaster
Who knows what will happen in next moment. The same was happened with people of Japan, everyone were busy with work but on 11 March 2011 whole Japan was shaken, with the earthquake which was several times more powerful than the worst earthquake in the history. The Fukushima Daiichi Nuclear Power Plant was destroyed by the 9.0 magnitude earth quake followed by tsunami. 3 out of 6 units were destroyed in this earth quake and tsunami. Resulting damage to environment and public health.
What happen to Nuclear reactors?
When the earthquake hit, the nuclear reactors all automatically shutdown. Within seconds after the earthquake started, the control rods had been inserted into the core and the nuclear chain reaction stopped. The earthquake destroyed the external power supply of the nuclear reactor. The reactor and its backup systems are designed to handle this type of accident by including backup power systems to keep the coolant pumps working. For the first hour, the first set of multiple emergency diesel power generators started and provided the electricity that was needed. However, when the tsunami arrived it flooded the diesel generators, causing them to fail. When the diesel generators failed after the tsunami, the reactor operators switched to emergency battery power. The batteries provide power for cooling the core for 8 hours. And they did but after 8 hours, the batteries ran out, and the residual heat could not be carried away any more. At this point the plant operators begin to follow emergency procedures. Here starts the real disaster and destruction. At this time people started talking about the possibility of core meltdown, because if cooling cannot be restored, the core will eventually melt, and will be contained in the containment. To control the increasing heat pressure, slowing down the temperature from 1200 Celsius and to protect the integrity of the vessel and containment, the operators started venting steam from time to time to control the pressure and temperature. Now real problem starts of toxicity and contamination of radioactive radiations.
Air pollution due to radioactive gases:
As the steam and other gases are vented. Some of these gases are radioactive fission products. Therefore, when the operators started venting the system, some radioactive gases were released to the environment in a controlled manner (ie in small quantities through filters and scrubbers). For three weeks there was evidence of partial nuclear meltdowns in units 1, 2 and 3. Also visible explosions, suspected to be caused by hydrogen gas, in units 1 and 3 and a suspected explosion in unit 2, which may have damaged the primary containment vessel.
Major releases of radionuclides, including long-lived cesium, occurred to air, mainly in mid-March. The population within a 20km radius had been evacuated three days earlier. The main source of radioactive releases was the apparent hydrogen explosion in the suppression chamber of unit 2 on 15 March.
Evacuation after Nuclear plant explosion:
But a release of radioactive gases into air caused 30 km area surrounding the plant to evacuate.
This large evacuation caused big concern about food and water supplies, and treatment of nuclear workers and people. During evacuating the city hundreds of people lost their life.
Water contamination:
A large amount of contaminated water had accumulated on site, but with the installation of a new treatment plant in June 2011 this was progressively being treated and recycled for reactor cooling. In 2013 a further, more sophisticated plant was commissioned. The persistence and long lived tritium limits the potential to release treated water to the sea. Some radioactivity has been released to the sea, but this has mostly been low-level and it has not had any significant impact beyond the immediate plant structures.
Impact on health due to radiations:
A 2013 WHO report predicts that for populations that would have stayed and lived in the most affected areas, and according to the LNT hypothesis, there would have been a 70% higher risk of developing thyroid cancer for girls exposed as infants. A 7% higher risk of leukemia in males exposed as infants, a 6% higher risk of breast cancer in females exposed as infants and a 4% higher risk, overall, of developing solid cancers for females.
Report issued by Govt of Japan:
The Japanese government estimates the total amount of radioactivity released into the atmosphere was approximately one-tenth as much as was released during the Chernobyl disaster in Ukraine. Significant amounts of radioactive material have also been released into ground and ocean waters. Measurements taken by the Japanese government 30–50 km from the plant showed caesium-137 levels high enough to cause concern, leading the government to ban the sale of food grown in the area. Tokyo officials temporarily recommended that tap water should not be used to prepare food for infants.
Number of death told:
A few of the plant's workers were severely injured or killed by the disaster conditions resulting from the earthquake. There were no immediate deaths due to direct radiation exposures, but at least six workers have exceeded lifetime legal limits for radiation and more than 300 have received significant radiation doses.
But according to recent report of Japan today states that “Data compiled by officials and police show that almost three years after the huge waves smashed ashore, 1,656 people living in Fukushima Prefecture have died from stress and other illnesses related to the disaster, compared with 1,607 who were killed in the initial calamity.”
Summary:
According to International Nuclear Event Scale, the overall plant rating is at Level 7 (major release of radioactive material with widespread health and environmental effects). The Fukushima nuclear disaster showed us once again that nuclear reactors are dangerous. Not only have they caused significant damage to the environment, the health of populations and to national economies. Thousands of people lost their lives due to this hazardous disaster and many other are going through stress. The whole area was contaminated, oceans are contaminated, aquatic life is contaminated, air is contaminated and food is contaminated. Therefore we have to take measures against such incident and save our earth and human being.
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