Unexplained plumes of radioactive steam have been rising from Fukushima’s Reactor Building 3, Could a major meltdown be on the way?
Fukushima’s Reactor Building 3 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 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.
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.
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.
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
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.
TEPCO has confirmed that via camera surveillance, that steam has begun to pour from Reactor 3, although they have “not been identified abnormal plant conditions.”
TEPCO is reporting that “radioactive steam has suddenly begun emanating from previously exploded nuclear reactor building #3 at the Fukushima disaster site in Japan.”
The corporation is not clear on the details of the sudden change at Reactor 3 because of “lethal radiation levels in that building.”
Summations from experts conclude that this may “be the beginning of a ‘spent fuel pool criticality (meltdown)’ involving up to 89 TONS of nuclear fuel burning up into the atmosphere and heading to North America.”
Educated guesses suggest that the steam is “coming from what’s left of the fifth floor of the mostly-destroyed building.”
TEPCO has admitted that “they do not know why this steam is being generated, but matter-of-factly revealed today (December 28) the steam was first spotted on December 19 for a short period of time, then again on December 24 and again on December 25.”
The accord is that “pellets of radioactive fuel, ejected when the reactor exploded, went into the spent fuel pool located above the reactor and have begun melting down so seriously they are boiling off the water in the spent fuel pool.”
Should this be the case “the situation could escalate rapidly out of control.”