Normally, circulation would channel the hydrogen and oxygen to a recombiner where they would be restored back to water, but in the hours after the reactors were shut down, hydrogen was accumulating and separating in the wetwell and reached a point where it was vented into the sparse steel-frame structure at the top of the reactor building.
They point out that emerging economies have been frantically accumulating real assets, such as assembly lines and office towers, but their generation of financial assets has not kept pace.