The answer to this, according to Dr. Noritaka Yusa of Tohuku
University, is fairly simple. Following the Tohuku earthquake of 11
March 2011, all nuclear reactors were shut down. Additionally, diesel
generators were switched on to ensure an adequate supply of water to
the nuclear plant. However, when the 14-metre tsunami hit Fukushima,
the diesel generators were destroyed and the sea water pumps were
damaged. This implied that sufficient water was not available for the
proper functioning of the cooling system resulting in overheating of
the fuel rods overheating and ultimate meltdown.
Dr. Noritaka of Department of Quantum Science and Energy Engineering,
Graduate School of Engineering, Tohoku University, who was at AIT on 23
February 2016, elaborated on how the lack of external power resulted in
the disaster. Fukushima-I did not have electricity, and it died; while
some of the other units at Fukushima, which had external power to
provide the cooling water survived, he remarked.
Explaining the historic background to the reliance of nuclear power in
Japan, Dr. Noritaka stated that Japan has extremely limited quantities
of coal and gas, and no oil reserves. Further, since the land mass is
not physically connected to any other country which makes transmission
of power extremely difficult. These factors contributed to Japan’s
reliance on nuclear energy.
He also spoke about the lessons learnt from the Fukushima disaster,
stating that both tsunami countermeasures and accident management
systems under severe disasters were insufficient. He remarked that
while the slogan that nuclear energy was 100 percent safe is an easy
way to communicate with lay audiences; but from an engineering
viewpoint, a 100 per cent safety impedes scope for improvements.
Dr. Noritake was introduced to AIT by Dr. Weerakorn Ongsakul of the
Energy Field of Study from AIT’s School of Environment, Resources and
Development (SERD).
