Hanford Engineer Works produced the 9 kg of plutonium for the bomb dropped on Nagasaki. It's among the most toxic nuclear waste sites and the place Japan is turning to for help dealing with the melted reactors in Fukushima.

Tokyo Electric Power Co. has sent engineers on visits to the Hanford site in Washington state this year to learn from decades of work treating millions of liters of radioactive waste. Hanford also has a method to seal off reactors known as concrete cocooning that could reduce the ¥11 trillion ($112 billion) estimated cost for cleaning up Fukushima.

Hanford stretches over some 1,500 sq. km of scrubland where thousands of technicians are decommissioning the nine reactors in operation from 1944 to 1987. Its laboratories and plutonium facilities were integral to the Manhattan Project to make the first atomic bomb.