Fukushima Nuclear Disaster Overview
On March 11, 2011 a 9.0 Earthquake, the fourth largest on record since 1900, occurred in the Pacific Ocean causing a series of large tsunamis to strike the eastern coast of Japan. Now called the Tohoku earthquake, it (and the subsequent tsunamis) caused one of the worst natural disasters on record with over 15,361 people killed, a million buildings damaged or destroyed, and a financial cost of $235 billion dollars (the most expensive natural disaster on record).
In addition to the large amount of damage caused by this natural disaster, it also caused one of the greatest man made disasters on record at Fukushima. Japan, a country that heavily relies on nuclear power, had a number of nuclear plants that were built near the eastern coast when the tsunamis struck. Fortunately Japan, a country that sits near two fault lines and has a history with experiencing earthquakes, had containment measures set in place for just such an occurrence. Once powerful enough earthquake tremors are recorded near Japan’s nuclear plants, they begin to shutdown and cool off. For the most part this worked, except at Fukushima.
At Fukushima the plants power failed during the earthquake, so the emergency power system along with the emergency cooling condensers had to be used. Less than half an hour after the emergency systems turned on, tsunamis began to strike the coast near the Fukushima power plant. A seawall 19 feet high was put in place around the plant to protect it against tsunamis. The waves from the tsunamis that hit Fukushima were over 46 feet tall, rendering the seawall worthless. After crashing over the seawall, this wave not only destroyed backup power to the plant but also wiped out key equipment that was part of the emergency core cooling system.
The destruction of key cooling equipment by the tsunami triggered full meltdowns of reactors 1, 2, and 3, thus beginning what we now call the Fukushima Nuclear Disaster. After the earthquakes subsided, cleanup began and radioactive damage was assessed. High levels of Caesium-134, Caesium-137, and some other radioactive isotopes were detected around the nuclear plant and in the ocean. Currently efforts are on-going to clean up the radioactive waste as a result from the meltdowns.
Molecular Sieve and Zeolites Role in Clean Up
The Fukushima disaster is only the second nuclear disaster (the first was Chernobyl) to receive a 7 on the International Nuclear Event Scale (INES), the highest disaster rating a nuclear event can be rated. The clean up process will see new technological developments as well tried and true methods during the clean up of radioactive waste.
One method that’s currently being used, and was used in the past, is using zeolites. Shortly after the disaster, the Japanese government began to order the dropping of zeolites in the oceans surrounding the disaster site. The Japanese government is hoping that zeolites (the one’s that the Japanese government are using have specialized in nuclear waste processing), will help to slow down radioactive contamination of the ocean. Zeolites had previously been used in the clean up of the 1979 Three Mile Island Nuclear Disaster in the United States.
Although dropping zeolite in the ocean seems like a desperate attempt to contain the disaster, Japan is also utilizing molecular sieve in the clean up process, too. The molecular sieve in use was specifically designed to capture Caesium, and is being used to treat radioactive wastewater that is on the disaster site. Since the disaster began over 43 million gallons of wastewater have been treated with this molecular sieve at Fukushima.
Experts expect the Fukushima disaster clean up to last decades. As the clean up continues adsorption technology will continue to play an important role in cleaning up the oceans, environment, and reducing the amount of damage that will be done to our atmosphere.