FUKUSHIMA earthquake and tsunami thread and aftermath

[refusnik]

On 10 December 1968, the facility was experimenting with plutonium purification techniques. Two operators were using an "unfavorable geometry vessel in an improvised and unapproved operation as a temporary vessel for storing plutonium organic solution."[citation needed] In other words, the operators were decanting plutonium solutions into the wrong type of vessel. After most of the solution had been poured out, there was a flash of light, and heat. After the complex had been evacuated, the shift supervisor and radiation control supervisor re-entered the building. The shift supervisor then deceived the radiation control supervisor and entered the room of the incident and possibly attempted to pour the solution down a floor drain, causing a large nuclear reaction and irradiating himself with a deadly dose of radiation. The shift supervisor's actions are the subject of a Darwin Award nomination

Homer Simpson?

Amazingly, one of the operators survived, even though he had his right arm and both legs amputated. He is still alive and is considered a hero. "Unfavourable geometry vessels" were a large glass can and a steel bucket

[Hyperduck Quack Quack]

Thermal imaging is a great idea, as it could probably be used to give a very good idea of some of the temperatures involved

Wouldn't the reactor and its vicinity show up as hot even in normal circumstances, and after what's happened the wreckage would be hot all around the reactor whether it had ruptured or not?

[chronyx]

A very helpful, carefully considered, factual and well-explained assessment.

Yeah, fits right in here.

[refusnik]

Don't be silly.

They dink tea in Japan and a Geisha would be pouring it for the journalist.

You don't believe the journalists actually get off their ars*s do you?

Oh, sure I do! They get off and even take a ride on an elevator sometimes (when doughnuts run out.)

The referred article has factual information extracted from an old gentleman in a nearby Tokyo park.

[billybong]

Another interesting point that's emerged from the reactor 4 building photos is that the outside walls of the reactor buildings don't seem to be, as the schematic diagrams seem to imply, made from well strengthened concrete

i.e. stengthened concrete similar to

but seem to be made from some form of concrete block panels (or maybe thin concrete) which seem to blow out relatively easily if there's an explosion.

i.e. maybe concrete block panels similar to http://www.ambdevelopments.co.uk/images/fullsize/AMBPhBuilding1Lg.jpg

So they're relatively flimsy and don't offer much containment if there are explosions - but a lot cheaper.

Hopefully they put more strength into the actual reactor containment structure - as well as the spent fuel containment pool walls and floor..

Edited March 19, 2011 by billybong

[Gigantic Purple Slug]

Wouldn't the reactor and its vicinity show up as hot even in normal circumstances, and after what's happened the wreckage would be hot all around the reactor whether it had ruptured or not?

You're right. But I would have thought that if all the water had boiled off and these stored fuel rods were getting as hot as some people suggest they can get (1000 degrees or so ?) they would have enough resolution in the imaging to see that and identify a hotspot at the top of the building. After all this pool is pretty big and contains a lot of rods and it's well separated out from the core, which I assume you would not get any good results from because of the containment building. Of course there would be a thermal gradient between the core and the pool on top. Maybe this would obscure things or complicate matters.

Of course I'm not going to claim I'm an expert in the thermal imaging of damaged nuclear reactors. Have had a go with the handheld cam a few times though. Useful things.

[Darkman]

"Radioactive plume will reach Britain in two weeks"

nice

http://www.dailymail.co.uk/news/article-1367524/Japanese-tsunami-earthquake-Nuclear-fuel-rods-exposed.html

[theonlywayisdown]

Option1 - they have actually thought of using thermal imaging but they have not released the pictures.

Option 2 - they haven't thought of it.

Most likely option 1, 99.9% certainty. We're talking about Japan here, the land of Nikon, Canon etc. high tech imaging.

now either:

a). images aren't that useful, and the temperature differences are negligible as not to reveal anything useful

b ). images show the real situation, but they don't want to release the images

Edited March 18, 2011 by theonlywayisdown

[copydude]

Yep, the initial risk was clearly bad but now the risk could be more or less instant death to take a peek (although I'm clearly speculating here).

Not far off. If the altnuclear site is to be believed, spending one minute at the railing of a spent fuel pool would be enough to receive a lethal dose. Which is why it is normally encased in concrete, of course. 'Taking a peek' isn't on.

I think this may explain some of the tardiness in dealing with the situation. A plant is a very hostile environment at the best of times and workers are drilled in safety procedures until they became a conditioned reflex. It must take a huge mindshift to suddenly go into kamikaze mode.

Staff was withdrawn from the control room quite early on - to a 'safe distance'. One actually wonders where the operations centre is now. A mile away? There are some cars around the plant on the chopper videos, but these could perhaps be abandoned as contaminated.

A robotic engineer wrote in to the Reuters site. Robots with tracks and prods capable of fine motor movements are commonplace. They have cameras and radio - so, a pair of hands and eyes. I don't know why such things haven't been deployed - maybe the time it would take to reprogram for specific tasks.

[Jack's Creation]

That video eralier with the 'white sticks' - was it just me or did they seem a little too bright for normal?

Here's the first video taken at Chernobyl where you can see the exposed rods. It does appear history is repeating itself, unfortunately.

[refusnik]

Staff was withdrawn from the control room quite early on - to a 'safe distance'. One actually wonders where the operations centre is now. A mile away? There are some cars around the plant on the chopper videos, but these could perhaps be abandoned as contaminated.

It has been noted before that those who plan and direct the operation should not be in the middle of the radiation threat. This will put them under unnecessary stress and reduce their usefulness up until they collect their 100msv or whatever the agreed emergency dose is now. I am sure there is no lack of volunteers to work on the site and they will be rotated as they collect their max allowed dose.

[interestrateripoff]

Most likely option 1, 99.9% certainty. We're talking about Japan here, the land of Nikon, Canon etc. high tech imaging.

now either:

a). images aren't that useful, and the temperature differences are negligible as not to reveal anything useful

b ). images show the real situation, but they don't want to release the images

Or c ) head in the sand time if we don't use thermal imaging equipment we can still deny everything.

Although won't spy satellites have such ability?

[Harry Sacks]

I agree with you but on the other hand my son and about half the kids in his school cough their lungs out on a regular basis. In his case until he was three, he spent more time in hospitals than in playgrounds because of it. So I think it's fair to say something is affectnig kids' breathing and is most likely some form of pollution. I wish I knew what it was and how to stop it.

I really don't see why being concerned or on the lookout for potential harm should be derided.

I sympathise, and suspect it's caused by NOx and HC emissions from cars. As I said, cars are bad for your health.

[Jack's Creation]

Here's a couple of very recent photo's. It doesn't look good -If that 's Corium seeping out of the side of that reactor then its game over.

Now, a later photo, Something seems to have reached the pipe at the bottom. The yellow mass appears to have darkened in colour.

[refusnik]

Here's the first video taken at Chernobyl where you can see the exposed rods. It does appear history is repeating itself, unfortunately.

The fuel rods are about half an inch in diameter, I doubt you can see them from a helicopter.

Edited March 18, 2011 by refusnik

[interestrateripoff]

Not far off. If the altnuclear site is to be believed, spending one minute at the railing of a spent fuel pool would be enough to receive a lethal dose. Which is why it is normally encased in concrete, of course. 'Taking a peek' isn't on.

I think this may explain some of the tardiness in dealing with the situation. A plant is a very hostile environment at the best of times and workers are drilled in safety procedures until they became a conditioned reflex. It must take a huge mindshift to suddenly go into kamikaze mode.

Staff was withdrawn from the control room quite early on - to a 'safe distance'. One actually wonders where the operations centre is now. A mile away? There are some cars around the plant on the chopper videos, but these could perhaps be abandoned as contaminated.

A robotic engineer wrote in to the Reuters site. Robots with tracks and prods capable of fine motor movements are commonplace. They have cameras and radio - so, a pair of hands and eyes. I don't know why such things haven't been deployed - maybe the time it would take to reprogram for specific tasks.

Yep you would have thought robots would have been deployed by now to asses the damage as well as start clearly cars/debris etc... out of the way for easy access.

Wow one minute and then game over.

[refusnik]

Now, a later photo, Something seems to have reached the pipe at the bottom. The yellow mass appears to have darkened in colour.

Bleh. Looks like a typical street in any Chavtown after a good cleanup. Plenty of darkening yellow masses and no more dangerous then Chernobyl.

[Jack's Creation]

The fuel rods are about half an inch in diameter, I doubt you can see them from a helicopter.

You're right, it's the graphite stacking. Used as moderators. here's a diagram:-

Here''s a translation of the russian;-

The man in the chopper: "What you see is a plant #2 chimney. To the right is a control center of the power unit #4. Turn it on! Higher! There! Hold it steady there! Keep it where the smoke rises! Where the smoke is! Keep it there! Hold it like this." Voice behind the camera: "What you see is a very rare footage. These red-hot spots is a graphite stacking. Its high temperature caused a powerfull updarft that carried radioctive particles from the well of the reactor."

Edited March 18, 2011 by Jack's Creation

[Gigantic Purple Slug]

Here's a couple of very recent photo's. It doesn't look good -If that 's Corium seeping out of the side of that reactor then its game over.

Now, a later photo, Something seems to have reached the pipe at the bottom. The yellow mass appears to have darkened in colour.

Those photos don't match up to me. There's more of the pipework in place in the lower one than the upper one. Also more of the side of the building in the lower one. I think the top one is the later one.

Why is it game over if the corium leaks ? If it leaks and soldifies thats OK AFAIK it forms a glassy matrix that seals in the particles. What you don't want is the particles becoming airborne like in the Chernobyl fire, but this can't happen if they are sealed up like this, even if they are exposed to the air.

[chronyx]

You're right, it's the graphite stacking.

Here''s a translation of the russian;-

The man in the chopper: "What you see is a plant #2 chimney. To the right is a control center of the power unit #4. Turn it on! Higher! There! Hold it steady there! Keep it where the smoke rises! Where the smoke is! Keep it there! Hold it like this." Voice behind the camera: "What you see is a very rare footage. These red-hot spots is a graphite stacking. Its high temperature caused a powerfull updarft that carried radioctive particles from the well of the reactor."

Thanks for that - very interesting.

[interestrateripoff]

http://en.wikipedia.org/wiki/Corium_%28nuclear_reactor%29

Corium, also called fuel containing material (FCM) or lava-like fuel containing material (LFCM), is a lava-like molten mixture of portions of nuclear reactor core, formed during a nuclear meltdown, the most severe class of a nuclear reactor accident. It consists of nuclear fuel, control rods, structural materials from the affected parts of the reactor, products of their chemical reaction with air, water and steam, and, in case the reactor vessel is breached, molten concrete from the floor of the reactor room.

For anyone like me who has no idea what Corium is and it's significance.

[refusnik]

Thanks for that - very interesting.

At the moment the radiation level at their height was about 100,000 msv / hour. Puts it into a perspective....

[CharlieChuck]

Those photos don't match up to me. There's more of the pipework in place in the lower one than the upper one. Also more of the side of the building in the lower one. I think the top one is the later one.

Why is it game over if the corium leaks ? If it leaks and soldifies thats OK AFAIK it forms a glassy matrix that seals in the particles. What you don't want is the particles becoming airborne like in the Chernobyl fire, but this can't happen if they are sealed up like this, even if they are exposed to the air.

In the physics forum link above, there's another picture, this one seems to be taken at a similar time to the lower one and shows whatever it is better. The building looks in a similar state to the top picture too, it might have just been the angle that makes it look like the wrong order.

[interestrateripoff]

http://en.wikipedia.org/wiki/Corium_%28nuclear_reactor%29

Corium composition and reactions

The composition of corium depends on the type of the reactor, specifically on the materials used in the control rods and the coolant. There are differences between PWR and BWR coriums.

In contact with water, hot boron carbide from BWR reactor control rods forms first boron oxide and methane, then boric acid. Boron may also be contributed to these reactions by the boric acid in an emergency coolant.

Zirconium from zircaloy, together with some other metals, reacts with water and produces zirconium dioxide and hydrogen. The production of hydrogen is a major danger in reactor accidents. The balance between oxidizing and reducing atmospheres and the proportion of water and hydrogen influences the formation of chemical compounds. Variations in the volatility of core materials influence the ratio of released elements. For instance, in an inert atmosphere, the silver-indium-cadmium alloy of control rods releases almost only cadmium. In the presence of water, the indium forms volatile indium(I) oxide and indium(I) hydroxide, which evaporate and form an aerosol of indium(III) oxide. The indium oxidation is inhibited by a hydrogen-rich atmosphere, resulting in lower indium releases. Caesium and iodine from the fission products react to produce volatile caesium iodide, which condenses as aerosols.[2]

During a meltdown, the temperature of the fuel rods increases and they begin deforming, in case of Zircaloy above 700–900 °C. If the reactor pressure is low, the pressure inside the fuel rods ruptures their cladding. High-pressure conditions push the cladding onto the fuel pellets, promoting formation of uranium dioxide–zirconium eutectic with a melting point of 1200–1400 °C. An exothermic reaction occurs between steam and zirconium, which may produce enough heat to be self-sustaining even without the contribution of decay heat. Hydrogen is released in an amount of about 0.5 m3 of hydrogen (at normal temperature/pressure) per kilogram of zircaloy oxidized. Hydrogen embrittlement may occur in the reactor materials. Volatile fission products are released from damaged fuel rods. Between 1300–1500 °C, the silver-cadmium-indium alloy of control rods melts, together with their cladding and volatile metals evaporate. At 1800 °C, the cladding oxides start melting and flowing. At 2700–2800 °C the uranium oxide itself melts and the core geometry collapses. This can occur at lower temperatures if a eutectic uranium oxide-zirconium composition gets formed. At that point, the corium is virtually free of volatile constituents that are not chemically bound, resulting in correspondingly lower heat production (by about 25%)[1] as the volatile isotopes are now relocated.[3]

The temperature of corium can be as high as 2400 °C in the first hours after the meltdown and can reach over 2800 °C. A high amount of heat can be released by reaction of metals (particularly zirconium) in corium with water. Flooding of the corium mass with water, or falling of molten corium mass into a water pool, may result in a temperature spike and production of large amounts of hydrogen which can result in a pressure spike in the containment vessel. The steam explosion resulting from such sudden corium-water contact can disperse the materials, forming projectiles that may damage the containment by impact. Further pressure spikes can be caused by combustion of the released hydrogen. Detonation risks can be mitigated by the use of catalytic hydrogen recombiners.[4]

[edit] Reactor vessel breaching

In absence of adequate cooling, the inside of the reactor overheats, deforms as the portions undergo thermal expansion, then structurally fails once the temperature reaches the melting point of the structural materials. The melt then accumulates on the bottom of the reactor vessel. In case of adequate cooling of the corium melt, it can solidify and the spread of damage is limited to the reactor. However, corium may melt through the reactor vessel and flow out or be ejected as a molten stream by the pressure inside the reactor. The reactor failure may be caused by overheating of its bottom by the corium melt, resulting first in creep failure and then in breach of the vessel. High level of cooling water above the corium layer may allow reaching a thermal equilibrium below the metal creep temperature, without reactor vessel failure.[5]

If the vessel is sufficiently cooled, a crust between the melt and the reactor wall can form. The layer of molten steel on top of the oxide creates a zone of increased heat transfer to the reactor wall;[1] this condition, known as "heat knife", exacerbates probability of formation of a localized weakening of the side of the reactor vessel and subsequent corium leak.

In case of high pressure inside the reactor vessel, breaching of its bottom may result in high-pressure blowout of the corium mass. In the first phase, only the melt itself is ejected; later a depression forms in the center of the hole and gas is discharged together with the melt, resulting in rapid decrease of pressure inside the reactor; the high temperature of the melt also causes rapid erosion and enlargement of the vessel breach. If a hole is in the center of the bottom, nearly all corium can be ejected. A hole in the side of the vessel may lead to only partial ejection of corium, retaining its portion inside the reactor.[6] Melt-through of the reactor vessel may take from few tens of minutes to several hours.

After breaching the reactor vessel, the conditions in the reactor cavity below the core govern the production of gases. If water is present, steam and hydrogen are generated; dry concrete results in production of carbon dioxide and smaller amount of steam.[7]

Reading this it does suggest a meltdown has occurred.

[chronyx]

At the moment the radiation level at their height was about 100,000 msv / hour. Puts it into a perspective....

Haunting to think that while they may have still looked, felt, acted, perfectly healthy when they got back from their mission they were in fact 'walking dead', just waiting to decay. True heroes.