[AnriXuinriZ]

as neo said above - a primary steam explosion is quite a serious risk.

[TineSeign]

Some casualties are feared because of the building collapse. Core is partially melted but nothing catastrophical. (official word)

edit: explosion propably was "just" high temp./pressure steam.

yeah, thats what i was thinking, hopefully the steam was "seconday" I.E. not the primary coolant , but the water that was heated by and cooled the reactor coolant.

I just read about the building collapse, information is spotty and some of it contradicts itselft, not an hour ago I read the story as "plants intact," reactor coolant pumps and backup services down....now theres an entire enclosure gone? As far as the core being partially melted Im not sure about that, I read that temperatures were well bellow 1000F, which is plenty bellow what I would think the tolerances would be.

Of course without knowing the facts and getting spotty info from sensationalized news sites, its hard to say anything for sure.

[TineSeign]

as neo said above - a primary steam explosion is quite a serious risk.

The core is still very hot, to us its VERY hot, to its normal conditions its quite "normal," however, if the pressure is relieved to atmosphere, it will turn to steam as it is well above 212F, If this steam is vented to earth Atmosphere, things will indeed be very bad. It all depends on the amount though. Another thing to consider is what is in the steam when it is bled. Im going to assume that there are plenty of nasty isotopes in the steam with long half lives and once they are airborne there is no stopping them. If this occurs, this disaster goes from " everything is under control, abliet shitty," to " Oh ****...."

Lets wait and see if the "white cloud" was from fire, steam and if it was from steam if it was reactor coolant venting, or cooling water from a secondary(not nuclear) system.

[thehhhyips]

Some more on the BBC web site.
http://www.bbc.co.uk/news/world-asia-pacific-12720219



Nothing on the IAEA
http://www.iaea.org/press/

[AnriXuinriZ]

Japan's NHK TV says officials measured the level of radiation at the entrance of the Fukushima-Daiichi plant at 1529 Japanese time. If people are exposed to this level of radiation for an hour they'd receive the same amount of radiation they normally would in a year, the report says.
yearly dose in 1 hour - thats not a small leak

[TineSeign]

Some more on the BBC web site.
http://www.bbc.co.uk/news/world-asia-pacific-12720219



Nothing on the IAEA
http://www.iaea.org/press/

I cant tell what that is? dust/debris cloud from something collapsing? Mabye the quake weakened one of the structures and it collapsed?

[AnriXuinriZ]

The BBC's Nick Ravenscroft was on his way towards Fukushima, but about 60km from the plant was stopped by the police and told it was too dangerous to proceed. He says there is lots of traffic coming in the other direction. Authorities in vehicles with sirens are making public announcements to the crowds 60 km and they are turning people away

[TineSeign]

yearly dose in 1 hour - thats not a small leak

Small leak is techincal jargin, there are several "levels" of leaks, spill,small leak, fast leak, and large leak, something like that. Leak indicates it is a constant flow and has not been stopped, spill would be a certain amount has been released. So when they say small,large etc, its not defining the level of radioactivity nor the dose one would recieve from proximity. A few drops of reactor coolant could yeild enough of a dose to cause serious harm, or hundreds of gallons could be almost harmless.

If they are indeed picking up readings that high on the average "around" the plant, then I would have to assume that reactor coolant, or RAM(Radioactive material) has somehow escaped containment. Untill I hear more information, In my opinion, this has gone from a natural disaster compounding into an incident at the plant, to a release of radioactive material from some source. This is bad. They now have to begin containment of the source, decontamination, determining the extent of the release, is it water borne? is it radiation from static sources? is it airborne? and they also have to continue working on getting the 4 shutdown cores to more stable "shutdown temperatures/pressures." this containment breach will make working out there much much harder.

[thehhhyips]

I cant tell what that is? dust/debris cloud from something collapsing? Mabye the quake weakened one of the structures and it collapsed?

They've just shown the explosion that produced that cloud - it was indeed a large explosion and that cloud picture was perhaps 2 to 4 seconds later.
As has been surmised, a steam explosion was one of the main concerns and it looked like a pressure vessel failing - certainly a long way from a controlled discharge.

Terrible situation there and SFA that anyone can do about it - just hope the engineers in the plant weren't hurt.

Just confirmed, explosion leaked radiation an hour ago!
Replay suggests main wave front from the explosion was straight up.
Not a Chernobyl, but very serious! People ordered to stay inside.

[AnriXuinriZ]

pumping coolant > 30 mins later a steam explosion> now we have radioactivity in a wider area. as for teh type its not reported but it most certainly doesnt help the safe full shut down.

edit:

Japanese authorities have extended the evacuation area at the Fukushima-Daini plant - also know as Fukushima II - to 10km, the same distance as for the Fukushima-Daiichi, or Fukushima I plant
precaution or `houston we have a problem`?

[thehhhyips]

This just misses the initial explosion, but gives an idea...
http://www.youtube.com/watch?v=kHlMlwcdw-k
try this
http://www.youtube.com/watch?v=pg4uogOEUrU
48 seconds in! Note the pressure wave front above it - that big doesn't happen without a serious explosion!

[TineSeign]

I just dont have enough information to acurately surmise what is happening at this point.

It may not be related to them feeding coolant, it could be a building collapse....or it could be a steam cloud from a secondary/auxillary service. Or the worst could have happened. One of the containment enclosures reached enough pressure to finally breach the containment and what we are seeing is a mixture of structual explosion and radioactive steam. However, remember that the core exploded from PRESSURE, not from going prompt critical and blowing the containment off like at chernobyl. At chernobyl the reactors fission reactions accelerated at such a fast exponential rate that the core had an un-determinate level of energy which caused the containment to explode and a **** ton of highly radioactive fuel spewed into the atmosphere. In this scenario we are dealing with reactors that are shut down, not enduring fission reactions and the isotopes are daughter products and less reactive....still dangerous. If the containment did explode from steam discharge, the effect is much less than chernoybl...but still bad. The wind carrying the radioactive particles could carry radiation for miles.

Lets get more info....

[AnriXuinriZ]

chernobyl was unique as it was a positive void co-efficient reactor , of which only russia made them , and they are dismantleing them as quick as they can tbh

[TineSeign]

I think the explosion was hydogen or oxygen, the vapor ring that blows upwards is clear, both of those gases are used in abundance in Nuclear plants, something might have caused a big hyrodgen or oxyen resovoir to explode, which caused the explosion, leveled the building and caused the debris/dust cloud.

However, an explosion of that magnitude could have damaged reactor coolant/containment services...

[TineSeign]

chernobyl was unique as it was a positive void co-efficient reactor , of which only russia made them , and they are dismantleing them as quick as they can tbh

Lol, yeah. A discussion had by many a nukes...what sense does "moar reactivity=moar power" Its nice to have for a quick start up I guess, but for land based 100% reactors who cares? i think it must have been a carryover from thier sub nuke plants where power transients were more common. Good thing we developed the PWR and figured out a great way to handle transients without relying on reactivy coefficient, but rather another more controllable factor

[thehhhyips]

As you say, early to judge but certainly can't see any way it was a simple building collapse due to the violence and wave front evident (refer to ~48s in the second video, may be hard to see in that low res' version) - I hope you're right and it was a secondary building/system that exploded, rather than a critical one or the main containment vessel.

Been a long time since I was reading up on Chernobyl but IIRC there were several problems, localised runaway reactions causing instantaneous explosions, the late addition of cooling water reacting with the superheated graphite causing secondary steam explosions and the burning graphite carrying off radio active particles in its smoke and convection currents.

Do you, or anyone else, have any info on the apparent flooding at the site after the tsunamis, etc, receeded? I was wondering if the actual ground levels had dropped as a result of the earthquake.

They're still replaying the clip - zoomed in there was a large building that completely blew apart! It looked like one of the reactor buildings - just to the right of the exhaust stack tower - I sure hope it was some other support facility, but it didn't look good as, looking at other previous images, it looks like what was identified as a reactor building - sometimes you really want to be wrong!

If you keep watching this - http://www.bbc.co.uk/news/world/asia_pacific/ - it should show it again.

[AnriXuinriZ]

bbc have a zoomed in but low res clip - 1 moment building there , next clear shock front then dust and building gone;

edit:


1000x radiation normal inside building - explosion reported to be inside a core building , either the roof or an outer wall

[lapyignipinge]

I think the explosion was hydogen or oxygen, the vapor ring that blows upwards is clear, both of those gases are used in abundance in Nuclear plants, something might have caused a big hyrodgen or oxyen resovoir to explode, which caused the explosion, leveled the building and caused the debris/dust cloud.

However, an explosion of that magnitude could have damaged reactor coolant/containment services...

Some experts also think it was hydrogen explosion.

[thehhhyips]

I think the explosion was hydogen or oxygen, the vapor ring that blows upwards is clear, both of those gases are used in abundance in Nuclear plants, something might have caused a big hyrodgen or oxyen resovoir to explode, which caused the explosion, leveled the building and caused the debris/dust cloud.

However, an explosion of that magnitude could have damaged reactor coolant/containment services...

That's what some of the reports suggest as a possibility. A release of hydrogen could build up quite high before igniting.

Looking for a building map of the site now.