The meltdowns at three nuclear plants at Fukushima, Japan almost three years ago were an economic disaster, but were these plants inherently unsafe? Did the Fukushima designs provide adequate safety during extreme circumstances?
The magnitude 9 earthquake that hit Japan in 2011 was its largest ever. However it was the enormous tsunamis that led to meltdowns. At Fukushima the spent fuel pools never leaked water in spite of the earthquake, its aftershocks, and tsunamis. Even Fukushima’s emergency power systems initially survived the earthquake, only to be soon destroyed by the tsunamis.
The nuclear plants at Fukushima were in an extreme situation. The electric grid and the emergency power systems were knocked out, leaving operators in a blackout condition. Tsunamis flooded various areas and buildings. Hydrogen generated by the meltdowns was not harmlessly vented. The containment venting systems could not be quickly opened because they lacked electric power. Reactor buildings were destroyed when the hydrogen that collected there exploded, sending debris flying and further impeding plant access. Post-accident plant improvements will prevent a recurrence of this venting issue.
The earliest environmental release of radioactive material started at 13 hours and was a small percentage of the total radioactive inventory. Small and delayed releases are consistent with previous blackout studies by the Sandia Laboratory on a similar plant, where no near term radiological health effects were calculated. This was confirmed by the World Health Organization which concluded that there were no early radiological health effects and long term health effects would be too small to be detectable statistically.
Beyond the economic losses, the major losses from Fukushima were fear, not fact, driven. More than 1,100 needless excess deaths came from over-evacuating and long term sheltering. Japan, Germany, and California, all with reductions in nuclear electricity, are burning more fossil fuels. Meanwhile, China, Russia, and South Korea strengthen their economic futures selling and servicing new nuclear plants worldwide. Misunderstanding the full story of Fukushima is a profound mistake.
Did the Fukushima designs provide adequate safety during extreme circumstances? How should our understanding, or misunderstanding, of Fukushima impact our approach to nuclear power?