Fukushima-is there a Major Meltdown ?

The Mystery Plume Rising Over Fukushima’s Reactor
Three

by Oliver Tickell

CounterPunch (January 01 2014)

Fukushima’s Reactor Building Three exploded on 13th March 2011 as a result of a
hydrogen buildup, breaching the building’s containment and emitting a huge
plume of radiation. The reactor itself is in meltdown.

And now fresh plumes of steam have been seen coming out the structure. These
have now been confirmed by Tepco, the owner of the nuclear plant, from 19th
December onwards. The company believes the steam is coming from the fifth floor
of the building.

However it does not know the cause of the steam. Lethal levels of radiation and
the physical damage to the structure have so far made entry and inspection
impossible.

Possibility 1: A meltdown is taking place

The Reactor Three 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.

Ever since the explosion Tepco has been concerned that if the spent fuel
storage pond dries out, the intensely radioactive spent fuel rods would melt
down and produce further significant radioactive emissions.

One possibility is that this process may now be taking place. In the event of
water loss from the pond, the water would begin to overheat and produce clouds
of steam, prior to a complete meltdown. If this is the case then a second major
nuclear disaster at Fukushima is in the making.

This explanation appears to be relatively improbable, however, and no official
warnings have been released on either side of the Pacific.

Possibility 2: ‘Corium’ has reached groundwater

Reactor Three 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.

This would also produce steam as the hot corium came into contact with
groundwater, while also releasing radioactive contamination to make its way
into the Pacific Ocean.

Possibility 3: Rainwater on stray fuel elements / Reactor

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.

And of course the same water could be reaching the hot reactor vessel.
According to a Fairewinds Energy Education posting on Facebook, the reactor is
currently producing about one megawatt of heat, equivalent to 1,000
one-kilowatt electric fires, so enough to produce plenty of steam.

This would provide the least worrying explanation for the steam, in that as the
radioactivity continues decline so will the heat production and the volume of
steam produced. If this explanation is correct, there is no reason expect any
catastrophic outcome.

However the steam is carrying considerable amounts of radiation into the
atmosphere and represents an ongoing radiation hazard.

_____

Oliver Tickell edits the Ecologist, where this article originally appeared: http://www.theecologist.org/

http://www.counterpunch.org/2014/01/01/the-mystery-plume-rising-over-fukushimas-reactor-3/

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