Reactor diagrams, photos of the Unit 3 blast damage, NHK English TV

[Robin Whittle]

In addition to the references I posted yesterday, pointing to daigrams
of the reactor and its containment building:

http://en.wikipedia.org/wiki/Talk:Fukushima_I_nuclear_accidents#References_of_potential_interest

here are some other items of potential interest:

Japanese TV, in English: http://www3.nhk.or.jp/nhkworld/.

The Australian Broadcasting Corporation has good coverage, and I have
frequently seen images there before they turn up on BBC or CNN:
http://www.abc.net.au .

For instance, a video of the Unit 3 explosion (or was this the second of
two explosions):

http://www.abc.net.au/reslib/201103/r733895_5942378.asx

There were some still photos too, but I can't find them now.

There are many interesting and presumably relevant photos at this page:

http://www.nucleartourist.com/areas/bwr-in1.htm

(I archived them, in case this site disappears.)

especially:

http://www.nucleartourist.com/imagemaps/rx-bldg1.jpg
http://www.nucleartourist.com/images/rflg-fl1.jpg
http://www.nucleartourist.com/images/rflg-fl2.jpg
http://www.nucleartourist.com/images/headlift.jpg

- Robin

[Fledi]

Given that now the highest radiation of 400mSv has been measured at
the No. 3 reactor, I suspect that huge explosion might have damaged
the containment. Wonder where the solid pieces flying up several 100
meters within the explosion plume came from exactly.

[Robin Whittle]

Hi Fledi,

You wrote:

My guess is that the debris falling down the left of that vertical cloud
was the equivalent of the yellow metal dome seen here:

http://www.firstpr.com.au/jncrisis/Boiling-Water-Reactor-cutaway-diagram-from-NRC.GOV-619x700.jpg

and in a photo here:

http://www.nucleartourist.com/images/headlift.jpg

The diagrams and photos also depict an octagonal piece of removable
floor, presumably of concrete. That too might have been blasted up. I
guess it was a hydrogen explosion inside the concrete and steel
structure which is the "secondary confinement" building. Some orange
flame came out the south side of the building. I am not sure that this
orange flame would result from a hydrogen air explosion, but perhaps
there was some hydrocarbon material in that part of the building.

I think the operators must have been having extraordinary difficulties
if they couldn't prevent the build-up of hydrogen, resulting in all
three reactors (or at least the reactors secondary containment buildings
and all control and monitoring systems) being severely damaged by
explosions.

They are releasing steam, with hydrogen, from the reactor's water body,
to the atmosphere. How hard could it be to let it straight out, rather
than building up inside the secondary containment space, or in the roof
over the refuelling floor, as seems to be the case with Unit 1? I guess
it must have been difficult or impossible - its just that I can't
understand why.

I wrote earlier that I guessed the Unit 1 explosion also came from
inside the secondary containment building, but now looking at the
DigitalGlobe satellite photos - see the first photo at
http://www.firstpr.com.au/jncrisis/ - it seems that Unit 1's refuelling
floor remains intact. So I guess it must have been a straight-out
build-up of hydrogen in the roofed area. That's a lot of hydrogen - and
I thought that area would have been well ventilated.

- Robin

[Thomas Fledrich]

The diagrams and photos also depict an octagonal piece of removable
floor, presumably of concrete.  That too might have been blasted up.  I
guess it was a hydrogen explosion inside the concrete and steel
structure which is the "secondary confinement" building.  Some orange
flame came out the south side of the building.  I am not sure that this
orange flame would result from a hydrogen air explosion, but perhaps
there was some hydrocarbon material in that part of the building.

If I understand correctly, the yellow dome+octagonal concrete floor composes the top of the drywell structure. If this is the case, the main explosion must have had occured inside the drywell, otherwise they wouldn't have been thrown up to that altitude. This explosion might have been triggered by a H2 one in the outer building, though. So now the question would be if the top of the reactor pressure vessel itself is still in place and tight. The steam plume that can be seen in the DigitalGlobe image would probably be bigger, if it would vent directly from inside a completely open reactor, I guess, but there might be some leak.

An orange flame doesn't result from a clean hydrogen explosion. It could have been hydrocarbons or just some mixing of the reacting gas with smoke/dust.

 

I think the operators must have been having extraordinary difficulties
if they couldn't prevent the build-up of hydrogen, resulting in all
three reactors (or at least the reactors secondary containment buildings
and all control and monitoring systems) being severely damaged by
explosions.

Yes this is pretty much like a nightmare with the earthquake and tsunami. I'm surprised, though, that the electric equipment controlling the valves wasn't housed in a watertight building that could stay dry in spite of a tsunami/flood washing over it. After the second explosion they were down to one working fire pump to cool three reactors according to news. Wouldn't want to be in their place for sure.

 

I wrote earlier that I guessed the Unit 1 explosion also came from
inside the secondary containment building, but now looking at the
DigitalGlobe satellite photos - see the first photo at
http://www.firstpr.com.au/jncrisis/ - it seems that Unit 1's refuelling
floor remains intact.  So I guess it must have been a straight-out
build-up of hydrogen in the roofed area.  That's a lot of hydrogen - and
I thought that area would have been well ventilated.

The first explosion was a "simple" clean hydrogen one, unlike the second and much smaller

you can compare here:
No. 1: http://www.youtube.com/watch?v=5KzABEkkc10
No. 3: http://www.youtube.com/watch?v=T_N-wNFSGyQ

I still thought they would get things under control at that point. But now with even the offline reactor No. 4 burning and likely releasing radioactive particles from spent fuel rods, the future is starting to look really bad for the people and area around the plant and nuclear power usage generally.

(sorry for double post)
Fledi