The main radionuclide released from
Fukushima Daiichi was iodine- 131.
It has a half-life of 8 days. Other than
that, cesium-137, which has a 30-year
half-life and Cs-134 was also produced
and dispersed which has a two-year
half-life. On 7 September 2011, TEP-
CO president Toshio Nishizawa said
that the four damaged reactors will be
scrapped and it will take 30 years to
finish. In 2021, they are planning to begin
the removal of the melted fuel inside
the reactors.
It had been 9 years since the disaster and the cleaning of the neighboring area is still going on.
Significant efforts are being taken to clean up radioactive material that escaped the reactor. Washing
down buildings and scraping away topsoil is still happening. According to the plans, all areas
with radiation levels above 1 millisievert per year would be cleaned. Radiation levels between
5 and 20 millisieverts should be cut down to 60% by 2013. On 22 February 2012, TEPCO started
cementing the seabed near the plant to prevent the spread of radioactive materials into the sea.
Some 70000 square meters of the seabed around the intake of cooling water would be covered
with 60 centimeters thick cement. And it prevents the spread of contaminated mud and sand at
that place for at least 50 years.
The Japanese government introduced 3 zones according to radiation levels.
1. No-entry zones, with annual radiation exposure of 50 millisieverts or more. At these places,
habitation would be prohibited.
2. Zones with annual radiation exposures between 20-50 millisievert. Here, former residents could
return, but with restrictions.
3. Zones with exposures of less than 20 millisieverts per year. In these zones, the residents would be
allowed to return to their houses.
Six years after its evacuation, Namie is about
to reopen.
The cost of this disaster is already up to 202.5
billion dollars. And it could rise to 650 billion
dollars.
Nuclear energy is one of the cheapest and
cleanest energy sources in the world. But, if
something goes wrong, it can be a huge disaster
and we have two such experiences until
now. Therefore,
we should try to
make it safer and
prevent disasters
like Fukushima
and Chernobyl.
N.K.B.Lakshan
Madhushanka Bandara,
Third Year - Department
of Electrical and Electronic
Engineering,
Faculty of Engineering
University of Peradeniya.
Page 42
University of Peradeniya GAUGE Magazine