Tepco today confirmed that (unexplained) plumes of steam have been rising Reactor 3.

There's a chance Fukushima could be in the middle of another meltdown.



Possibility 1 - a meltdown is taking place

The Reactor 3 fuel storage pond still houses an estimated 89 tonnes of the plutonium-based MOX nuclear fuel employed by the reactor, composed of 514 fuel rods.


Possibility 2: 'corium' has reached groundwater

Reactor 3 itself contained 566 fuel rods, and has experienced a complete meltdown. The location of the molten fuel, known as 'corium', is unknown, but it may have burnt its way through the reactor base and entered the underlying soil.


Possibility 3: rainwater on stray fuel elements

An alternative explanation is that the steam plumes could be caused by stray fuel pellets and reactor rod fragments - which themselves produce significant amounts of heat - coming into contact with rainwater percolating through the damaged and roofless structure. Of the three choices this is probably the least serious.

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[link to www.theecologist.org]