On March 11, 2011 the fourth most powerful earthquake in modern history struck off the
coast of eastern Japan.
Powerful waves, up to 40 meters in height, inundated coastlines and washed away entire towns.
This left the Fukushima Daiichi Nuclear Power Station 75 kilometers from the epicenter,
under a dire threat.
The earthquake cut electrical lines to the plant, and the tsunami flooded emergency generators.
Without power to pump cooling water over the nuclear fuel, three reactor cores melted down.
Gases generated from overheated fuel exploded and blew apart three buildings.
The accident resulted in the greatest release of radioactivity in the environment since
the Chernobyl nuclear disaster of 1986.
Ten years since this disaster, cleanup at the power plant is in its early days.
For one, different damage to each unit required unique structures to enable fuel retrieval.
The structures for units 2, 3, and 4 have been completed; a temporary protective enclosure
surrounds until 1 while engineers study how to safely remove the fuel.
Major hurdles remain, including figuring out what to do with the water used to cool melted
and resolidified fuel debris.
Over a thousand massive tanks packed throughout the campus contain over 1.24 million tons
of water contaminated with radioactivity.
A water treatment system removes radionuclides and reduces radioactivity.
Still, traces of some isotopes persist, like tritium, an isotope of hydrogen.
Tritium has a minimal impact on human health unless ingested,
and small amounts are naturally present in seawater and the atmosphere.
Japan’s Ministry of Economy, Trade, and Industry has proposed slowly releasing the water into
the ocean and air, but environmental groups, the fishing industry, and neighboring nations
condemn this approach.
It’s uncertain exactly how the discharge of water would impact marine life,
but there are concerns about other radioactive isotopes of ruthenium, cobalt, and strontium
accumulating in fish.
A solution needs to be found soon, as water storage will likely run out in 2022.
Melted fuel debris has yet to be extracted from any of the units, but workers will try
to retrieve samples of the debris using a remotely operated mechanical arm in 2022.
As the cleanup progresses, another aspect of the nuclear accident has emerged:
how the disaster impacted evacuees.
While the accident was in progress,
those living within 20-kilometers of the plant, and in some adjacent highlight contaminated areas, were evacuated.
Some places have reopened for habitation, but about 37,000 people
are still unable to return home.
Uprooting thousands of people had serious consequences for human health.
Among 715 residents evacuated from five Minamisōma nursing homes, the risk of death was 2.7 times
higher than before the disaster.
There has also been an increase in the lag between when women recognize possible breast
cancer symptoms and when they see a doctor, making treatment more difficult.
Researchers say that better preparing receiving facilities in the future
could help alleviate the stresses of displacement.
The lessons learned studying the challenges of decommissioning the Fukushima Daiichi power plant
plant and evacuation, could lead to improved responses to future disasters.