Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[AtomicWombat]

the molten whatever from fourth floor is not evident on below picture and it is hot, smoke or steam rising were it it the ground.

I suspect that the molten material is visible in the first photo, but it is in the form of a white-yellow or silver-yellow tongue that is only just starting to flow from the hole in the wall. This may be the fuel-assemblies in the early stages of meltdown.

In the later videos the corium (I suspect) has "aged" (oxidised or undergone some other chemical modification) and appears a darker grey than the concrete wall it is slowly flowing down.

Note that corium can vary in appearance:
http://en.wikipedia.org/wiki/Corium_(nuclear_reactor)#Three_Mile_Island_accident"

http://en.wikipedia.org/wiki/Corium_(nuclear_reactor)#Chernobyl_accident"

Note that in TMI the "samples were generally dull grey, with some yellow areas", after a long period in oxygen free environments. The yellow of course reflects "yellow cake" uranium oxide.

In Chernoby 5 different forms were identified. The type most likely related to the mass on the side of the building in the videos is chernobylite:

http://en.wikipedia.org/wiki/Chernobylite"

I admit I cannot be sure that this material in the photograph and videos is a result of "meltdown" of the fuel assembly, but surely it should be checked.

 

[AntonL]

I suspect that the molten material is visible in the first photo, but it is in the form of a white-yellow or silver-yellow tongue that is only just starting to flow from the hole in the wall. This may be the fuel-assemblies in the early stages of meltdown.

the yellow tongue discussed earlier is from a different location, I marked it in the uploaded file.

If it is Corium then how does it get from bottom of holding tank to the top floor?

 

[Smed]

Can anyone speculate as to how this event would have unfolded if the Fukushima site were operating ABWRs or an equivalent technology rather than the Mark I units?

Thanks.

 

[AtomicWombat]

the yellow tongue discussed earlier is from a different location, I marked it in the uploaded file.

I think there is a perspective problem. The concrete facia has come away from the frame of the building This can be seen at 0:53 in this video:

If it is Corium then how does it get from bottom of holding tank to the top floor?

I had this discussion with Astronuc. The hole is below the top floor. A ridge running around the external casing marks the reactor floor in units 2, 3 & 4. The hole is entirely below this ridge.

 

[AntonL]

I think there is a perspective problem. The concrete facia has come away from the frame of the building This can be seen at 0:53 in this video:

And at 0:53 off this video you can see the glowing red mass

 

[Borek]

And at 0:53 off this video you can see the glowing red mass

This whole corium thing is a pure speculation.

I am not saying you are wrong, but I have a feeling you tend to interpret everything as confirming the idea. Thats a dangerous approach, it is easy to delude yourself. Pictures are taken using different cameras and in different lighting conditions (think white balance), in different weather and so on; color differences don't mean much in such a case.

 

[Astronuc]

Can anyone speculate as to how this event would have unfolded if the Fukushima site were operating ABWRs or an equivalent technology rather than the Mark I units?

Thanks.

The ABWR containment is more robust than MkI.

See these presentations:
www.ne.doe.gov/np2010/pdfs/abwrauxilarysystems.pdf[/URL]
[PLAIN]www.ne.doe.gov/np2010/pdfs/ABWRSafety.pdf[/URL]

See this view of the plant layout.
[PLAIN]http://www.gepower.com/prod_serv/products/nuclear_energy/en/downloads/gea14576e_abwr.pdf

Note the location of the SFP.

Note the location of the DGs, well above ground level. Not shown is the DG fuel supply.

 

[AntonL]

Red, yes. Glowing, I don't know. It may be one of the "red spots" Tcups pointed to in the earlier photo. Could it belong to red painted machinery, such as a crane?

Note in above photo two square panels above the gaping hole with yellow tongue
and now compare to latest below and the panel of upper floor has been destroyed now triangular
and a red mass is observed on a floor higher than yellow mass (now black) that tcup observed

 

[AtomicWombat]

Note: two square panels above gaping hole with yellow tongue
and now compare to and the panel of upper floor has been destroyed now triangular
the red mass observed is a floor higher than yellow mass (now black) that tcup observed

Yes. The red mass is still below the main deck of the reactor. I also take it that the "two panels" now hang so far from the original face of the wall that the obscure an additional 2 panels observed in the front view on the extreme RHS of the building.

I'm off to bed Anton. That lava-like flow looks suspicious.

 

[romillyh]

I've been following the discussion (as a lurker) about the hole in the side of no. 4 bldg and previously wasn't convinced. Now I am -- something is coming out of that hole and seems to have reached the pipe at the bottom. The photos/grabs from different days show this growth very clearly.

I attach an enhanced crop of the flyover frame at ca 0:53 in case it's of use.

IF melted spent fuel is able to flow out of the pond, what does this say about the state of the pond? I.e. can fuel slag flow out over the top of the pool, or could this mean that the pool structure has been breached somewhere down the side? IF it has been breached, what prospects for filling with water?

Thanks for excellent discussion. It's my main way of following what's going on.

 

[TCups]

Gulp.

I would have preferred to have been wrong. Forget color if you aren't convinced about "glowing" red stuff. Check the photo for other signs of heat. Like the surrounding thermal damage to the exterior paint and structure, the melting and discoloration of the roof above, and the faint plume of dirty smoke still coming from the (flowing) tongue of lava-like material.

I believe that the downloaded fuel from the reactor at Unit 4 in the SFP melted down. I also read at one time a statement that indicated the concrete wall of the SFP had cracked or crumbled, but that the steel reinforcing wall was intact. So, it would seem likely that an intense heat source like the melted fuel rod assemblies could melt the steel of the pool and contribute to the volume of the lava like flow. It might also account for secondary fires in the generator oil, etc.

It seems to me that if operators were struggling, perhaps unsuccessfully, to prevent melting of fuel rods inside of three other reactor vessels, under pressure, and with at least some remnants of a cooling system intact, to the extent they could pump sea water into them, then, how much harder would it be to prevent melting fuel rods in an unpressurized pool with apparent complete loss of circulating cooling water? Add to that, additional spent fuel rods in the same pool just to make things more interesting. In retrospect, knowing this, doesn't this outcome seem very likely if not inevitable? Perhaps this was known early on, perhaps not.

 

[SredniVashtar]

Silly question: if the tongue of material was corium (and I'm not saying it is), shouldn't the radiation levels at the plant be much higher than those actually recorded?

 

[spankey]

yeah, try like 10,000 Rem/hr on contact. AT LEAST. They wouldn't be flying that close...

 

[artax]

Surely a thermal imaging camera has been used by now!, I don't know if gamma imaging cameras exist but maybe x-ray or something more relevant to nuclear accidents exist? and where's the Yankee Drone that was promised, this would be a remarkably usefull tool for surveying the reactors..

 

[jensjakob]

At least they have power coming in.

But - according to this (and quite logical):
http://translate.google.dk/translat...ttp://www3.nhk.or.jp/news/genpatsu-fukushima/

they need to use some time on evaluating the state of the installations at Fukushima - it makes no sense to connect power and start electrical fires...

A lot will depend on how badly the installations are damaged so far - and what can be disconnected before turning on the juice.

 

[turbo]

This is a bit off topic but relevant - anybody recognize this Nuke Plant?

San Onofre

 

[TCups]

And at 0:53 off this video you can see the glowing red mass

Hypothetical scenario:

The melted core rods went through the floor of the SFP. They plopped like one giant radioactive cow pie on the floor below with fires and explosions, then went out through the side wall one floor lower, which would not have been as thick as the wall of the pool or reinforced with steel.

The breeched pool, obviously now dry, may still contain additional fuel rods. Both the heat from the corium, if that's what it is, and the additional fuel rods have melted additional stuff (steel reinforcement, generators, piping, fuel handling machines, etc.). If the structures above melt, ie, the containment melts, then it would have nothing to stop it from pouring out the side of the building.

So, "corium" one floor below. Continuing fires. Stuff above melts and slags out the side of he building above the initial breech in in the floor of the pool and wall below.

https://www.physicsforums.com/attachment.php?attachmentid=33222&d=1300451324

A very ugly picture and very ugly scenario, if it's anything near correct.

 

[jensjakob]

It is definitely not corium. If there had been heat enough to create corium - there would have been severe radiation - as well as heat shimmer...

My guess is that we see e.g. hydraulic oil from a crane leaking down the facade.

 

[artax]

This video has some amazingly shocking footage of one of the reactors (possibly3) at 46 seconds there's some red or glowing stuff and at 55 seconds you can see the damage to the concrete structure. and are those (god forbid) fuel rods scattered all over? They certainly look the same length and dead straight, not like the concrete reinforement that shows up as distinctly different.

 

[Naty1]

I had the MISfortune to see Chu the US energy Secretary and the US NRC head having a "news" conference yesterday afternoon (Thur PM, US)...it was embarassing...I don't think they gave one fact...where do such people learn to talk so vaguely? They skirted EVERY question...

No basis for the US setting a 50 mile evacuation zone around Fukushima was given...just "precautionary"...no radiation readings, no explanation what was verified and what was not, ...If that accident happened here and those bozos were saying the same thing, I'd be REALLY worried...

Other times I watched Hannity (Fox) , van Sustern (Fox), Cafferty (CNN), and from Japan Shep Smith (Fox) and Anderson Cooper (CNN?) ... ...and several others, one on MSNBC ...I sure hope they report politics more accurately than tech stuff...terrible,terrible,terrible!

It was reported that CNN was using environment activisits as "experts" and did not reveal the strong political bias of those people in the "reports"...I did not see THAT...

Michio Kaku said something like "the end is near" early this week...meaning meltdown was almost certain...way to hype!

Only 0'Reilly(Fox) did not make a fool of himself and that was only because his segment was so short...

I've told previosuly friends and family : If there is ever a report of radiological or chemical weapons attack or accident, keep clear of the area and if you have to move, stay UPWIND...

 

[jensjakob]

Okay, interesing.
30 seconds into this, there is also the red glowing something - I think it is at reactor 2?:
http://www.youtube.com/user/responsejp#p/a/u/2/y3Lg88ECaCE

 

[artax]

I noticed that fire the other day when I saw this vid. That's reactor three, two is virtually fully intact. but that looks more like an ordinary flame fire to me. What worries me is those rods.
Anyone?

 

[spankey]

can anyone pull a screenshot/still of the section in the video you are talking about...I'm unable to get reliable youtubage where I'm at.

I reiterate, if there were actually corium flowing around the place, the airborne release would be much larger than it is now being reported, and the radiation levels on the ground would be extremely large. Again, think like 10,000 Rem/hr with corium flowing around... We are NOT seeing any evidence of levels that high.

 

[artax]

how do you screen grab from you tube?

i'll try this
http://www.youtube.com/watch?v=z9fKtXDaQVc&feature=player_detailpage#t=54s

no just starts playing the vid there I'll photo my screen!

 

[spankey]

blow it up full screen, then use the printscreen button, and copy it into paint, and save it...

 

[SredniVashtar]

can anyone pull a screenshot/still of the section in the video you are talking about...I'm unable to get reliable youtubage where I'm at.

Let's see if I can do it

Yep, the image got through. Not sure if that's what the other poster meant, though.

 

[aamrwc]

If the pumps don’t work this weekend how much trouble are we in? If they do what are the implications? If rods are melting down and you add water do you get recriticality or a restart of the fission process? Is that like having an open air reactor? I’ve heard more talk of the concrete option why haven't they done this yet? What are the implications of that? What are risks of that option? What happens if they do encase the plant(s)? How long will the area around the plant be uninhabitable for how long? And how far will this area cover? How big a relocation problem will there be? How long will it remain radioactive? Cesium half life 30 years? If it remains radioactive, do radioactive winds blow south to Tokyo? What are the implications of that? Are we on the verge of the worst case scenario? Radioactive Tokyo?

 

[spankey]

Thanks for the screenshot.

I see what you are referring to, and it is hard to tell exactly what that might be.

Check out Wikipedia to see what kinds of levels Chernobyl had. (They had Corium flowing around that place)

http://en.wikipedia.org/wiki/Chernobyl_disaster#Radiation_levels

Vicinity of the reactor core 30,000 Roentgens/hr
Debris heap at the place of circulation pumps 10,000 Roentgens/hr
Debris near the electrolyzers 5,000–15,000 Roentgens/hr

Again, hard to tell, but I don't think we're hearing about stuff on that order of magnitude.

 

[rhody]

A sobering read: http://www.guardian.co.uk/world/2006/mar/26/nuclear.russia" (five years old: 26 March 2006)

At 1.23am on 26 April 1986, a series of explosions destroyed Reactor No 4 of the Chernobyl nuclear power station, three kilometres from Pripyat in the then Soviet Republic of Ukraine. Fifty tons of uranium fuel from the reactor core vaporised immediately, and were blasted high into the atmosphere; a further 70 tons of uranium and 900 tons of highly radioactive graphite were dispersed into the area around the reactor, starting more than 30 fires; the 800 tons of graphite that remained in the reactor core caught fire at once, creating a radiological inferno that would burn for 10 days, sending a continuous plume of lethal radionuclides roiling into the sky. The Soviet government would wait nearly three full days before acknowledging that an accident had taken place, and did so only after the drifting plume set off radiation alarms in a nuclear plant in Sweden. The contaminants, which included plutonium isotopes with a halflife of 24,360 years, eventually traveled around the globe, depositing radioactive material as far away as the lakes of Japan and the hill farms of north Wales. It was not merely the most devastating accident in the short life of the nuclear power industry; it was the greatest man-made disaster in history.

and

The RBMK was regarded as the workhorse of Soviet atomic energy, thrifty and reliable - and safe enough to be built without an expensive containment building that would prevent the release of radiation in the event of a serious accident. In fact, the reactor had serious design faults: when run at low power it was dangerously unstable and difficult to control; additionally, for the first four seconds after being inserted, the control rods would do the opposite of what they were supposed to - instead of slowing reaction, they would cause a sudden power surge. Under normal conditions these faults were not regarded as dangerous; but were the reactor ever to be pushed beyond its normal limits, they could prove catastrophic.

and

It was an apocalyptic sight: flames shot into the sky; sparks showered from the severed 6,000-volt cables hanging from the smashed circulation pumps; burst water and nitrogen tanks dangled in the air above the red-hot wreckage of the reactor hall; and from the centre of the building, an unearthly, delicate, blue-white light shot upwards into the night - a shaft of ionising radiation from the exposed core. 'I remember thinking how beautiful it was,' Yuvchenko says.

Amazing how Yuvchenko stood there, transfixed, until being quickly pulled away by his colleague, Tregub.
and finally...

The graphite in Reactor No 4 had been burning for almost 24 hours when the Chernobyl Commission decided the only way to extinguish the fire was to smother it. The scientists suggested sand, boron and lead, to absorb radiation and cool the melting core - 4,000 tons would do it, dropped into the blazing reactor from the air. On the afternoon of the 27th, two Mi-8 helicopters from Kiev began the first of hundreds of firefighting sorties. The pilots navigated through a forest of pylons surrounding the power station to hover 100 metres above the burning building, and, aiming by eye, dropped individual bags of sand from the helicopters' open doors. The radiation directly over the reactor was such that the pilots soon began being sick in the air; eventually they started flying in respirators, and sliding lead panels under their seats. By 1 May, they had dropped 4,450 tons of sand into the reactor.

But on 2 May, the engineers and physicists at Chernobyl made a horrifying discovery: the temperature of the core and the volume of radionuclides rising from it were both increasing. They suspected that the whole helicopter operation had been a terrible mistake: the sheer weight of everything they had dropped on the reactor from the air - including 2,400 tons of lead - had not only caused structural damage but was pressing the hot reactor core against its concrete base. And if the uranium reached meltdown temperature - 2,900C -a single sphere of molten fuel would burn through the concrete foundations of the reactor building, and keep going until it reached the water table. At that moment, there would be another explosion, exponentially more devastating than the first; the three remaining reactors would be destroyed in a nuclear blast that would render Ukraine, Belarus and Russia uninhabitable for decades to come.

'That was the most terrifying thing,' says Veniamin Prianichnikov. 'We were petrified of meltdown, walking around like zombies.'

A plan was devised: to freeze the Earth around the reactor with liquid nitrogen, and then build a heat exchanger in the ground beneath it to cool the core and prevent meltdown. Prianichnikov himself was sent in with temperature and radiation probes to discover how long they had before the core burned through the two metres of concrete foundations; meanwhile, miners were summoned from the coalfaces of Donetsk and the subway projects in Kiev to dig tunnels beneath the reactor. The scientists feared that pneumatic drills could disturb the foundations of the reactor, so they worked with hand tools, in conditions where wearing protective clothing was practically impossible, amid extraordinary fields of radioactivity. To freeze the ground, all the liquid nitrogen in the western Soviet Union was sent to Chernobyl: when it didn't arrive quickly enough, director Brukhanov received a late-night telephone call from the minister in charge of the operation. 'Find the nitrogen,' he was told, 'or you'll be shot.'

On 10 May, the fire finally subsided; it now seems possible that the graphite simply burnt itself out. The nitrogen was found, and the subterranean heat exchanger built, but by mid-May the temperature of the core had dropped to 270C; the exchanger was never even turned on. 'The miners died for nothing,' says Prianichnikov. 'Everything we did was a waste of time.'

Possibly things to be learned and applied here, to prevent similar mistakes...

Rhody...

 

[Astronuc]

FYI - this shows some of the features
http://nei.cachefly.net/static/images/BWR_illustration.jpg

http://www.world-nuclear-news.org/RS_Insight_to_Fukushima_engineering_challenges_1803112.html

 

[jensjakob]

I found this really good picture of reactor 4, the fuel-loader, an the SPF in the background:
http://www.dailymail.co.uk/news/art...ami-earthquake-Nuclear-fuel-rods-exposed.html

 

[jensjakob]

:-(
http://www.nirs.org/radwaste/atreactorstorage/alvarezarticle2002.pdf

 

[jensjakob]

More pictures from Nuclear works:
http://www.ibtimes.com/articles/123943/20110317/japan-earthquake-tsumani-fukushima-nuclear-plant-helicopters-reactor-meltdown-radiation-leak-fuel-ro_1.htm

 

[Astronuc]

I found this really good picture of reactor 4, the fuel-loader, an the SPF in the background:
http://www.dailymail.co.uk/news/art...ami-earthquake-Nuclear-fuel-rods-exposed.html

That is the reactor cavity and the columns are the bolts that hold the top (head) of the pressure vessel on.

The transfer canal leads toward the back under the fuel handling machine and the spent fuel pool would be under or behind the fuel handling machine.

 

[jensjakob]

This is a real nice picture of a SFP, showing the door to the reactor compartment:
http://img.ibtimes.com/www/data/images/full/2011/03/17/75371-dd.jpg

So - can one of the problems in Fukushima be that this door is damaged, and that is why they can't keep the waterlevel up?