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Saturday, 24 October 2015

Where is the core?

TEPCO released a news release on October 20, 2015 titled "Fukushima Daiichi Nuclear Power Station Unit 3 reactor containment vessel (PCV) for internal survey result of (Bulletin: October 20, carried out in minutes)" [Japanese Version], they didn't provide an English Version.

Outline of PCV internal investigation (video, temperature, dose)

TEPCO released inspection video and a PDF of their use of a camera to look inside of what remains of the #3 Reactor at Fukushima. Temperatures were about 30 degrees centigrade and the radiation level about 1 Sievert, One sievert carries with it a 5.5% chance of eventually developing cancer and is equivalent to 100 REM in older measurements. 6 Sieverts is a fatal dose.

In each image, the pictures clearly show extensive damage to the reactor containment vessel. Cracked walls, deposits of material, possibly corium or some burn residue. Fire damage.

In image on page 4 you can see what clearly look like Burn damage on the structures above where the core would be.

On Page 5 they disclose that the walls are badly damaged with support structures pulled away from the containment vessel

What is missing from the images is an image of the Core. TEPCO claimed that #3 exploded with a hydrogen explosion caused by the heat of the reactor cladding and cooling rods catalyzing water separating into hydrogen and oxygen and then burning together. But if that were so there would be remains of reactor all over the place. So the question is,....

Where is the reactor?

The answer is that the explosion was probably part of a "burn out" and the fuel was "aerosolized." The reactor probably got so hot and it's fuel started melting and "flashing" and burning, until enough burned away to quiet the uncontrolled chain reactions. But TEPCO doesn't say where the fuel went. They imply that some if it melted down through the floor. But it is just as likely that those explosions we saw on March 14, 2011. I remember watching the images. And indeed the FOIA Archives describe the situation on the 16th as:

"they described Unit 3 as having a 3 zirconium/water reaction ongoing. And they described 4 Unit 4 spent-fuel pool as having been substantially damaged to the point that the walls were no longer effective at retaining water." [NRC doc]

So we can guess where the reactor is. In our lungs. But of course, we have to keep on asking TEPCO to tell us the truth, because speculation is easy. We need the facts.

Further Readings:
The official version at the time:
Enews on Engineer opinions
Spent Fuel detected in fallout:
Miles O'Brien:
Unit 4 explosion and melt through 1.2.3 Unit of Fukushima Daiichi nuclear power plant: insider translation from Pattie L. Brassard
Image of #3:
Related article:
NRC Doc:

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