There's been so many BS news stories out there, it makes me sick.

Nobody delivered "coolant" to this plant.  Billary is a dumbass.

Radiation levels are elevated, by some reports to the tune of 1000 times in the control room.  This can mean many things, but if these elevated reported radiation levels are sustained, fuel damage is a real possibility.


Good informative link


A couple of simplified drawings:









From what I can gather from various sources, the quake shut some of the plants down.  It's hard to tell if any physical damage occurred directly to the quake, but a loss of coolant accident due to system piping breaks is the design accident for these plants and their installed safety systems.

At some point, it appears a loss of offsite power occured at some of the plants.  The plants have emergency diesel generators, but it appears that some of them failed.  

A loss of coolant accident with a loss of offsite power is the worst of the worst for a nuke plant.  The safety systems are designed for this, assuming the safety systems are operable and stay operable throughout the event.

Tsunami damage could have caused subsequent damage to equipment like the EDGs, safety systems, etc.

Another thing that needs to be understood is that the primary goal in a nuclear accident is to keep the fuel covered with water.  If none of the fuel is exposed, a major meltdown is unlikely.  If they can't keep water on the fuel, the fuel will overheat and melt.  When this happens, radiation levels will go up dramatically, as fuel configuration is lost and the nuclear reaction can go on uncontrolled.

To keep the core covered with water, you need an operational pump, electricity to run that pump and a source of water.  The second pic shows typical emergency cooling systems available to reactors.  You can see there are many and each has redundant trains.  This includes emergency diesel generators.  If their diesels were damaged in one way or another, it would be my priority to get temporary power to these plants that needs it ASAP and enough electrical cable to wire the generators directly to equipment if needed.  You now have power, a pump and the damn ocean, if needed, for water.

Many plants have a last resort system that pump borated water into the reactor.  The boron is a poison to the reactor.  A reactor with enough boron in it cannot start or sustain a nuclear reaction.  You still have to keep a boron poisoned reactor covered with water, so the above still applies even after this system is used.

Even with safety systems out of operation, there's things that operators can do.  As you see in the first pic, the core is housed in a primary containment.  The core has pressure relief valves on it that relieve to the containment building.  The containment building pressure is the pressure that is being advertised at 1.5 times normal.  This is due to steam being relieved from the reactor to the containment building.  You can see the relief valve(s) depicted by the pink line on the second drawing.  The containment building is designed to a certain pressure.  If it approaches that pressure, operators can vent gasses from the containment building.  This is the "release" that people talk about.  It is normally done through a filtered and monitored system or systems.  Therefore, little actual radioactive material is actually released.

I'll add more as it comes to me and/or question trigger answers.


If there's other nukes out there, chime in and correct me or add as necessary.

thanks OP! So do you think they are fucked?

Thanks for the info.

Adding:

The Reactor Building, as shown in the second pic (the heavy black outline around all the pumps), is also a containment.  It's called secondary containment.  It can contain leakage from primary containment.  Not massive leakage, mind you, but it's another barrier to a release of radioactive material to the environment.  It has filtered and monitored release paths, in case they are needed.

All is good the media is doing its job and scaring the shit out of everybody.

Well if that cracks Toyota won't need headlights, the Cars will glow in the dark.

I can't say this enough - elevated levels of 1000 times at the control room and 8 times at the site boundary are not a good sign.

It could tell you that core damage has occurred in at least one of the plants.  BUT, BUT, BUT................even if a core is damaged it could be fully contained in primary and secondary containment and little to no release may happen.  It's not a guarantee either way.

Site map - control rooms are likely on the ocean side of the plants.  Where a plant is labeled, the small square/rectangle is the containment building.  There's a larger rectangle on the ocean side which is the turbine building.  The control room is probably between the containment building and turbine building or there may be two control rooms between each plant.  It looks like the plants are connected at the turbine buildings.

Another important concept to understand is the farther away you get from a radiation source, the less the dose you receive.  I showed on a graph and a real simple pic.

That's why there is dose 1000 times normal at the control room, which is usually very near the reactor, and it's only 8 times normal at the site boundary, which is usually very far from the reactor.






As the above simlified pic shows, as you get closer to the radiation source, more of it's radioactive emmissions will hit your body.

Just tell me when I have to make an improvised fallout shelter when radioactive material gets scattered over the U.S. by prevailing winds.

If you don't have one already, it's too late.

Shim in, go home

Thanks Mongo –– that is the first article I have read written by someone who understands the concepts and can apply them to the situation.


The diesel generatoprs failing hours later, during 6 and 7 richter after shocks makes sense, finally.

BWR technology isn't everyone forte

Correct.  Public officials should keep their damned mouths shut unless they are absolutely sure that they are putting out correct info, that includes news agencies.  If you don't know, there's nothing wrong with reporting a problem without making up details that make no sense.

Thanks for this info .

+1    +1

Very good news release on the Japanese reactors and their conditions

TEPCO website has blow by blow incident reports

I have to ask... if everything is evacuated, where are the people controlling everything, or is it done remotely or dudes in suits?

Almost everything safety related can be controlled from the control room.  This control room has ventilation systems that keep it habitable, meaning contamination can't get in.  It is physically configured to be able to have people in it even in the event of the worst accident.  They'll still get radiation dose, though.  There are people that go out to the equipment for various reasons, but in cases like this their jumps are short and to the point, to reduce dose and contamination potential.

They are evacuating people who live around the site.  Site workers likely are locked in and can't leave.

I know they asked for help from the Navy in monitoring radiation levels.  And that's all, for this.  The scary thing is these are BWR's and have a normally higher level of radiation than PWR's.  But still this is no where near a TMI or chernobyl level of event.  One good thing about a BWR is all they need to do to remove decay heat is inject water into the core and dump steam to blow down tanks.

BWRs have contamination throughout the plant because radioactive steam flows through the entire plant.  PWRs have a steam generator which is a physical barrier between contaminated and noncontaminated systems.

While your statement is true, the overall rad levels in a BWR don't really add to the probability of a release due to core damage.  It's just part of doing business in a BWR.

Break it down for me. Should anybody outside of those areas directly around the plant be worried?

I've been ignoring the reactor stories deliberately till some time passes because I'm assuming the reporters are going to go "ZOMYGOD! Ratings!" and the majority of the reads are gonna go "ZOMYGOD! Evil Reactors, that I know jack and shit about, are gonna blowup and nuke the world!"





Edit:



I know there are many reactor designs that have been made over the past 70 years, but I guess they could not get the rods all the way in and get rid of the residual heat?





 

 

Not now.  If they get the "2" pump's running they should be fine.  Thing about a BWR is they can not run on natural circulation for forced cool down.  They have to have a main coolant pump to push water into the core.  Then a second pump to push cooling water through the heat exchanger to cool the steam back to water.

If they don't get the pumps running soon, then if you live in Japan or plan on visiting those sites soon then yes.

Thanks....Great report.



Do they store their spent material on site and is there any concern with this stuff?

Nearly all do.  Gives it time to "quiet down".  No concerns, stored under water.



 

that gave me a chuckle this morning.  there's a whole ocean full of coolant that surrounds the entire island.  hope they can get the pumps running soon.

I'm going to bump Mongo's thread this morning.  This limk has been updated to address recent events, such as the "explosion".


"Television cameras trained on the plant caputured a dramatic explosion surrounding unit 1 at around 6pm. Amid a visible pressure release and a cloud of dust it was not possible to know the extent of the damage. The external building structure does not act as the containment, which is an airtight engineered boundary within. The status of the containment is not yet known. "

I'm trying to get all the info I can find together to get some type of coherent opinion.  I saw the explosion video on Fox, but the distance and angle didn't tell me much.

Link

This is not good.  The above link has a video that shows what, I believe, is one of the containment buildings, or the structure around the containment building, blowing up.  There are four lined up in a row.  One definitely blew up.  Not good.  Not good at all.


I'll throw out a few things.  The link talks about a hydrogen explosion.  In the plant I work at there's two possibilities for a hydrogen explosion.  First, our generator is cooled with hydrogen.  If it was released quickly and ignited it could cause an explosion, but not one that would demolish a building.

The second is a reaction that happens when fuel cladding is being compromised.  Fuel cladding is a thin layer of metal that contains the fuel.  When it "burns", it gives off alot of hydrogen, enough to be a major concern.  We have systems in place at the plant I work at to eliminate hydrogen in accident conditions.  There has been some recent analysis that says we don't really need these systems anymore, so I'm not sure if this is a real concern today or not.  Someone in the past thought it was a concern, though.

Let's extrapolate a little.  If, in fact, they had fuel damage, hydrogen production is possible.  If they were venting gases from primary containment, hydrogen would be in there.  If they got hydrogen into secondary containment and somehow ignited it, that could be what you saw there, the secondary containment building blowing up.  I will say that our secondary containment building is very thick, reinforced concrete, so our building would not blow up like that.

The other scenario is that building was not around the primary containment and I'm completely wrong.



TEPCO company news release



This is NOT a good report.  Two things concern me.  

Radioactive iodine is a product of fission, usually contained in the fuel element.  If large amounts of radioactive iodine is being released, fuel integrity is compromised.

Elevated radiation levels "exceeding limiting value" tells me that something happened to the fuel - some level of meltdown - that is causing increased radiation levels.

IMO, there is fuel damage at that plant.  It may or may not be contained.  Iodine released could be due to controlled venting of the containment building to maintain its integrity.  Radiation levels would go up even with an intact containment building.

I was always under the impression that the stored stuff is hot and that it needs a supply of cold water constantly cooling it down too and that if it doesn't get it ......it can catch on fire too.



 

Cesium has reportedly been detected in the vented steam.   That is indicative of an incipient core meltdown,  if the meltdown

hasn't already started.    This is far from good.





CJ

When I read that this morning, I knew just enough about nuclear reactors to know I was reading BS.

Thanks for the informative thread.

Fuel that is in spent fuel pools out side of the primary or secondary shielding is not truely hot as in terms of decay heat.  Yes it produces some but long term storage is dry storage.

Tag for later

Word on nuke sites is that they are flooding the hole containment building.  This is normally a option of last resort.  If this is the case they are writing off using this reactor.  

But if this is the case, its good news.  As this will provide a massive cooling heat sink and limit problems.

outer containment building is gone... break through of core is said to be imminent...

Source?

fuck, i will be keeping my CBRN gear instead of turning it back in.

Reuters - look on drudge

I don't know much about fallout, but that charts seems a bit melodramatic.  



 

Any idea how the Japanese design differs from the American design. Seems to me there's a lot of, what appears to be, chunks of metal sheet flying through the air.

That chart is bullshit.





 

Just off the top of my head, with what I've gathered to date, probably not too much.  That building was probably nothing more than a shell around more important structures.  

Yeah... As you said, our secondary containment structures are a couple feet of steel reinforced concrete. Theirs are probably nothing more than a steel frame with sheet metal cladding.

The reason I.m asking, I work at VY. Invariably, friends, relatives and neighbors are going to ask me about this. I'd just like to have my facts straight.

By the way. Which plant do you work at?

Our refuel floor is on top of the reactor building and is considered part of secondary containment (I think it is, anyway).  It is nothing more than structural steel with sheet metal.  In fact, the sheet metal panels are designed blow off with "explosive bolts" (just bolts torqued to a certain value designed to sheer under a certain load).

We had a tornado blow through last June.  A number of these panels worked as designed and went away under the stress of the tornado.

Ahhh... Well, you just answered one of my questions.

I'm pretty sure our reactor building is made the same way.

I'm curious, what's the normal PSIG of the steam as it leaves the reactor in something similar to the Japanese plant in question?

So is the footage we're seeing run over and over again, the containment building actually undergoing a "catastrophic failure" ?

I am no expert by any stretch of the imagination, but considering there was four containment building before the blast and only three after, I'd say that is the definition of "catastrophic".

IMO, no.  It was an event on the top of the building, which is commonly the refuel floor.  

There's still a primary containment and reactor vessel to contain most, if not all of the fuel in the core, regardless of its configuration.

The releases to date are very likely intentional to maintain primary containment pressure, to make sure it doesn't exceed design pressure which would cause a breach.  A breach must be avoided at nearly any cost.  A few vents of radioactive gas is worth it in the long run.

New thread for the continuation of the Earthquake/Nuclear issues?
(it would be good to have Mongo's posts highlighted)