Tokyo: The Japanese nuclear power plant that was closest to the epicentre of last year`s earthquake suffered more ground shaking than Fukushima but was largely undamaged because it was designed with enough safety margins, nuclear inspectors said on Friday.
The Onagawa plant in northern Japan recorded temblors that exceeded its design capacity and the basement of one of its reactor buildings flooded. But the plant maintained its cooling capacity, its reactors shut down without damage to their cores and there were no signs of major damage to crucial safety systems.
The UN nuclear watchdog`s inspectors found the Onagawa plant managed to avoid a catastrophe like Fukushima because its safety systems "successful functioned," said Sujit Samaddar, who led the 19-member International Atomic Energy Agency mission.
"With the earthquake of this magnitude, we would have expected the plant to have more damages, and that was not the case," Samaddar said. "This indicated there were significant margins in the designs."
In contrast, the 9.0-magnitude earthquake on March 11, 2011, knocked out a power line at the Fukushima Dai-ichi plant and generated a large tsunami that flooded its emergency generators, destroying the plant`s cooling systems.
Catastrophic meltdowns occurred in three reactors, releasing radiation that has tainted the surrounding environment.
The plant has since stabilised but more than 100,000 people still can`t go home due to radiation fears, while work to decommission the plant will take about 40 years. It was the world`s worst atomic accident since Chernobyl.