[mattyb]

From here : BBC News - Japan warns of small radiation leak at nuclear plant

It is understood that the earthquake cut electricity supplies to the power station, and the back-up generators did not come into operation when the outage occurred.

I've worked in two seperate companies where senior management hasn't allowed time or budget to test disaster recovery situations. One time after a major power outage the generators did their job just as they should. And then died 30 minutes later as everyone was still congratulating themselves on what a fine job they did. Not enough fuel in the tank for the generators.

[ghporter]

That is just about the number one failure with backup power systems. "Oops, generator starts but runs dry" doesn't cut it at hospitals, air traffic control facilities, nuclear power plants, and other important facilities. But the Japanese reactor issue may well have simply been that the generator was damaged by the quake. An 8.9 magnitude quake can shred just about everything.

[imitchellg5]

From what I've heard, it seems as if the diesel generators died due to water?

[subego]

That's actually kind of funny.

I mean, as nuclear reactor hit by a natural disaster jokes go.

[subego]

Also, seems ironic the sucker couldn't just power itself.

At least on the surface, I'm sure there's a good engineering reason for it.

[turtle777]

It was very smart to set up those plants directly at the coast, sort of like the first defense against a tsunami wave

-t

[Spheric Harlot]

Originally Posted by turtle777 

It was very smart to set up those plants directly at the coast, sort of like the first defense against a tsunami wave

Couple difficulties with that:

Nuclear power plants need cooling water.

No huge, major rivers inland.

IIRC, Japan is 70% mountainous; it's only the coastal areas that're really practical to build on.

[ghporter]

The way nuclear power plants work is by producing lots of steam through cooling the core during a reaction. When the core is shut down-which happened appropriately and automatically in this case-it no longer produces enough heat to effectively generate enough steam to run the turbines and generate electricity. A "shut down" reactor cannot generate its own electricity without some new technology to produce power at low steam pressures through an additional cooling system. But these specific reactors still produce a LOT of heat, and they need active circulation of core coolant to keep the temperature low enough for safe internal pressures.

As Spheric Harlot pointed out in the other Japan earthquake thread, the reactor was in danger of a "Three Mile Island" problem: a core melt event that is less catastrophic than a true "China Syndrome" event (the real thing, not the movie). But at the same time, the reactor vessel was having to contain internal pressure from "low pressure steam" generated by ineffective cooling. My first bit of news about Japan today was that there was an explosion at the plant with the release of a lot of radioactivity. At first glance, this could simply be that the reactor vessel could no longer contain the internal pressure and it failed. This is a Very, Very Bad Thing if it's what happened.

Considering that the plant was fully exposed to the tsunami and that its diesel generators were not able to operate after the surges, it looks like a design problem in their disaster avoidance structures. But pointing fingers won't help anything.

[turtle777]

Originally Posted by Spheric Harlot 

Couple difficulties with that:

Nuclear power plants need cooling water.

No huge, major rivers inland.

IIRC, Japan is 70% mountainous; it's only the coastal areas that're really practical to build on.

Uhm, yeah, build it 10 miles away from the coast, and the logistical effort to pump water is minimal. Easy fix to get out of harms way of the Tsunami.

-t

[WhaMe]

Originally Posted by turtle777 

Uhm, yeah, build it 10 miles away from the coast, and the logistical effort to pump water is minimal. Easy fix to get out of harms way of the Tsunami.

-t

That's fine until an earthquake ruptures your 10 mile long pipeline that is carrying the cooling water.

[turtle777]

Originally Posted by WhaMe 

That's fine until an earthquake ruptures your 10 mile long pipeline that is carrying the cooling water.

True, but you gotta build this thing earthquake resistant anyways. It's not like building at the coast will help you with energy and pipes. They still need to be build sturdy.

-t

[Laminar]

turtle, go ahead and call up Japan and tell them they didn't think through things well enough, because they're a people known for haphazard decision making.

[turtle777]

Geez, dude, I already did.

-t

[turtle777]

Oh, and while you're at it: maybe you can also let the WJS know that the Japanese are perfect when it comes to building fail-safe nuclear power plants:

Plant Safety Systems Questioned From Failed Reactor - WSJ.com

-t

[Dork.]

No, building on the coast seems to have been the correct choice. By all accounts the structures directly protecting the actual reactors are still intact. Being near the coast they can try the last-ditch "fill the darn thing with seawater" option that they appear to be trying for the first problematic reactor, without having to worry about getting the seawater to the reactor.

They built the reactors themselves to withstand the earthquake and tsunami, and that worked. But the emergency generators (which were supposed to kick in when the reactors automatically shut down and provide power to maintain cooling) didn't survive the tsunami.

You would think they would keep some generators stashed somewhere in the country that they could airlift over for just such a problem. It must not be that simple, I guess.

[Spheric Harlot]

Originally Posted by turtle777 

Uhm, yeah, build it 10 miles away from the coast, and the logistical effort to pump water is minimal. Easy fix to get out of harms way of the Tsunami.

I'm not a nucular physician, but if cooling is so absolutely critical, I'd want it to immediately available, and not piped through miles of tubes where it can heat up nicely in the late summer, and then piped back into the river/sea.

I'd think ten miles of pipe would be FAR more likely to create a cooling problem, even at much lower-magnitude earthquakes, such as they happen all the time.

Either way: the option of pumping in sea water would not have been possible in your scenario, so we can assume they knew what they were doing and made the right choice.

At 9.0 on the Richter scale (just corrected upwards), all bets are off, anyway. Just pray your compromises were some of the least catastrophic ones.

I'm still praying.

[turtle777]

Using sea water for cooling is the Hail Mary, the last resort in trying to cool down the reactor.

By now, there are three reactors that are failing.

The general problem is clearly that the safety of those reactors was not as good as it was always portrayed. In case of TEPCO, this was hardly a secret. They have been caught cheating with safety documents over and over again.

-t

[ghporter]

It's not the "safety of the reactors" that's the issue. It's the failure of backup power to be available-due to the generators being overwhelmed by water. Not a reactor issue, a "we didn't think of protecting diesel generators from that much water" issue. Boiling water reactors have had fewer spontaneous problems (as in "not caused by some natural disaster") than US-style pressurized water reactors, in part because they're simpler. I guess nobody ever imagined a magnitude 9 earthquake WITH a tsunami centered so very close to this power plant. That's referred to as "bad luck," not "bad reactor safety."

Aside from not having the generators protected, I think the real issue here is why it took so long to get water moving in the reactors. I think it will have had something to do with the fact that the whole north of Japan seems to be devastated, with most of the rest of the eastern coast being slightly less bad off. Focusing on a problem caused by multiple failures that could not be reasonably foreseen, even though it's extremely serious and endangers a lot of people, doesn't mean the reactors at the center of this problem are unsafe. It means that things happened that were not predicted. That's all.

(Sorry if I sound harsh here, but anti-nuclear sentiment without fully understanding the technical issues involved always bugs me, and the suggestion that a workhorse reactor design with an outstanding safety record is unsafe because of an extreme Act of God is the kind of thing that Luddites and know-nothings use as a starting gambit to eliminate even the safest "scary" options.)

[Spheric Harlot]

I think, without wanting to kick off a political discussion, that there is absolutely no way to secure nuclear power plants against this kind of situation.

Redundancy, fail-safes, whatever: how would you guarantee ANY infrastructure or technical system through a 9.0 earthquake?

[ghporter]

Originally Posted by Spheric Harlot 

I think, without wanting to kick off a political discussion, that there is absolutely no way to secure nuclear power plants against this kind of situation.

Redundancy, fail-safes, whatever: how would you guarantee ANY infrastructure or technical system through a 9.0 earthquake?

Other than additional protection for the diesel generator(s) and redundant backup generators in different physical locations, I have to agree. By definition a magnitude 9 quake produces "near total destruction," and tsunami surges ten meters high qualify as "biblical destruction." The key here is how long such a reactor system can be left without active cooling, and how quickly even a severely devastated country can get teams to it to restore cooling. In this case it was "not long enough" and "too long."

[Dork.]

We know how to build structures to withstand heavy earthquakes. It's expensive, though, and may not be the top priority for some projects. (One would assume it would be for a Nuke plant, though.) While you can't eliminate risk totally, you can mitigate it to the point where a failure is extremely rare.

I know there were a lot of homes and smaller buildings swept away, but we have not heard much about larger buildings toppling in cities, due to Japan's stringent building codes. Even the nuclear problems they are having are not due to direct damage from the quake and tsunami, but due to the fact that their contingency planning didn't account for what might happen if the backup diesel generators were wiped out. I'd say the actual structures did pretty well.

[Cold Warrior]

I read today that newer models prefer the water above the reactor, that way it could be cooled without power to pump it. These models worldwide are mostly so old, I think we did the best we could at the time they were built.

[Spheric Harlot]

Hardly a comfort, though, and, at least in this country, cause for a complete risk re-assessment of nuclear power.

[turtle777]

Originally Posted by Spheric Harlot 

I think, without wanting to kick off a political discussion, that there is absolutely no way to secure nuclear power plants against this kind of situation.

Redundancy, fail-safes, whatever: how would you guarantee ANY infrastructure or technical system through a 9.0 earthquake?

That's not the topic.

The topic is that there were repeated warnings that the safety systems were not in best shape, and the company TEPCO repeatedly got caught lying about the condition of its safety systems.

I'm not saying that it would have prevented these issues (because you can't know that), but it's hardly comforting to know that the company cut corners when it came to safety.

-t

[ghporter]

Skimping on safety in any industry is stupid. If they had indeed not kept things up to snuff, I'd definitely start pointing fingers. But doesn't TEPCO also run many other nuclear power plants that didn't have this happen? It would sound like "let's look into this" rather than "shoddy work was a major factor" in this case. I hope I'm right on this, I really do.

[imitchellg5]

Skimping on safety is actually brilliant from a business stand point. If you spend a lot of money on safety proofing things, then you've wasted it all unless the infinitesimal chances of a disaster actually occurring are realized. That's why airlines and car manufacturers are always finding loopholes to get around regulations.

[subego]

Originally Posted by Spheric Harlot 

Hardly a comfort, though, and, at least in this country, cause for a complete risk re-assessment of nuclear power.

I'll do a tsunami risk assessment for you. Gratis.

[ghporter]

Originally Posted by imitchellg5 

Skimping on safety is actually brilliant from a business stand point. If you spend a lot of money on safety proofing things, then you've wasted it all unless the infinitesimal chances of a disaster actually occurring are realized. That's why airlines and car manufacturers are always finding loopholes to get around regulations.

All it takes is one "oops," and your "brilliant strategy" is down the tubes-along with all the executives who signed off on such a policy. Which is why real business does NOT skimp. Instead real businesses do at least the minimum required by law and regulations, so as not to wind up in bad headlines. Take a look at what's happened to Massey Energy since it's become public knowledge that several of its principles actively "skimped" on safety. They're going to have to spend billions of dollars to close a mine they'd spent billions to keep open despite its horrible safety record, and several principles, their security boss for example, are up on charges.

A good safety record in industry is bankable. It's little things like more than the minimum number of eyewash stations and an extra check on saw guards to make sure they're still working that keep people on the job and cut expenses for Worker's Comp and lawsuits. When an industry looks at safety in terms of "let's dodge these rules," that industry WILL be caught and everybody and their grandmother will know who was responsible because it'll be front page news. Try to get an executive job after winding up on page one with a caption that reads "responsible for 4 injuries, one fatal." Not happening.

In Japan, it's kinda worse, since executives there often follow cultural norms and commit suicide instead of "shaming their families." That may be the easier way out for them, but it doesn't help anything.

Back on topic, this disaster is exactly why corporations hire imaginative people to come up with "what if" scenarios so they can be prepared. These are at best educated guesses. In the case of the Fukushima power plant, it seems like nobody considered "bad 'epic' science fiction disaster" scenarios.

[imitchellg5]

In America, businesses skimp on safety then lobby lawmakers to make exceptions and it all gets buried. Every day.

[Dork.]

Originally Posted by ghporter 

In the case of the Fukushima power plant, it seems like nobody considered "bad 'epic' science fiction disaster" scenarios.

In particular, based on what I've been reading, they never considered the possibility that a tsunami would be taller than their sea walls. That seems to be the key thing here: they deliberately put their diesel generators on low ground, and a lot of their electrical wiring was in basement rooms, because they thought the sea walls would protect them. (I read this on the NYT earlier this morning, but I can't seem to find the link right now).

So, not only did their diesel generators fail, but the electrical system to power the pumps was probably damaged and flooded, which explains why they couldn't just ship in another generator.

[turtle777]

Most nuclear powerplants in Japan were build to withstand earthquakes of magnitude 7-8.

Back in the 60ies and 70ies, there were no recent quakes with magnitude > 8, so it was not deemed necessary to build to that standard.

-t

[Spheric Harlot]

They're built to 8.25 Richter, IIRC.

[nonhuman]

Originally Posted by Spheric Harlot 

At 9.0 on the Richter scale

The Richter scale is logarithmic. your 'correction' just doubled the stated severity.

</pedantry>

[turtle777]

Some interesting information in this WSJ opinion piece.

William Tucker: Japan Does Not Face Another Chernobyl - WSJ.com

Seems like technology in today's reactors is far advanced compared to those old Gen II reactors from the 60ies/70ies.

My prediction is that nobody will care about this, and nuclear power severly discounted as a power source.
This will accelerate our general energy problem. Cue those fools that think wind and solar can make up for this.

What's even worse: all the fear of nuclear will prevent from newer and more safe power plants to be built.
The result is that we will have to live with the older, less safe plants for a longer time.
F*cking retarded.

-t

[The Final Dakar]

This thread is making me dizzy.

[Spheric Harlot]

Originally Posted by nonhuman 

The Richter scale is logarithmic. your 'correction' just doubled the stated severity.

</pedantry>

It wasn't my correction.

[nonhuman]

Originally Posted by Spheric Harlot 

It wasn't my correction.

Ah, I misinterpreted. Everything I've seen still says 8.9 though.

[Spheric Harlot]

It's since been corrected upwards in some sources, notably the New Scientist.

[Goldfinger]

How long do they need to keep cooling the reactors ? Don't they cool off enough after a few days ? Or do they need perpetual cooling ?

[ghporter]

According to a physicist from MIT that I heard on the radio yesterday, much of the current heat is coming from highly radioactive but very short half-life isotopes that are fragments from uranium fissioning. Over the next several days the temperature should start coming down as those isotopes decay. Keeping the reactors flooded with cool seawater over the coming week or so should be enough to ensure the cores settle down to safe, manageable temperatures.

[Spheric Harlot]

Here's a take on the technical background by Dr Josef Oehmen, research scientist at MIT, in Boston.
"He is a PhD Scientist, whose father has extensive experience in Germany’s nuclear industry.
Ref: http://morgsatlarge.wordpress.com/"

World Party: 3/11 Japan Earth Quake News#17 Fukushima Nuclear Reactors

When designing a nuclear power plant, engineers follow a philosophy called “Defense of Depth”. That means that you first build everything to withstand the worst catastrophe you can imagine, and then design the plant in such a way that it can still handle one system failure (that you thought could never happen) after the other. A tsunami taking out all backup power in one swift strike is such a scenario. The last line of defense is putting everything into the third containment (see above), that will keep everything, whatever the mess, control rods in our out, core molten or not, inside the reactor.
When the diesel generators were gone, the reactor operators switched to emergency battery power. The batteries were designed as one of the backups to the backups, to provide power for cooling the core for 8 hours. And they did.
Within the 8 hours, another power source had to be found and connected to the power plant. The power grid was down due to the earthquake. The diesel generators were destroyed by the tsunami. So mobile diesel generators were trucked in.
This is where things started to go seriously wrong. The external power generators could not be connected to the power plant (the plugs did not fit). So after the batteries ran out, the residual heat could not be carried away any more.

His assessment is that the "plant is now safe and will remain safe".


Unfortunately, he appears to be wrong.

(He also says that contaminated sea water used for cooling will be removed to treatment plants - we already know that it's being pumped back into the ocean, which is completely understandable given the circumstances.)


A continued account of what's happening, here at the New Scientist:

Short Sharp Science: Radiation spike as crisis intensifies at nuclear plant

First, "there is no possibility of a nuclear explosion," explains Richard Wakeford of the University of Manchester's Dalton Research Institute. He says any such fears are "science fiction", as there is nowhere near enough radioactive uranium 235 in the reactor to create a nuclear explosion.

The real fear is that harmful radioactive material will escape from the reactor core.

[…]

But even if the rods do melt and sink to the base of the reactor vessel, this shouldn't be a problem unless the vessel itself breaks open. "The big question is whether the containment holds," says Wakeford. "There was a meltdown at Three-Mile Island, but the vessel remained intact."

and a later update (at the top):

According to The New York Times, a third explosion at the plant is now confirmed to have damaged the containment vessel around the plant's reactor no. 3.

I haven't been able to find out what time frame we're looking at for the cooling.

[Big Mac]

It's somewhat amazing that with the large earthquakes Japan routinely has no one responsible for the nukes had the foresight to think about multi-stage contingency plans to cool the plants in the aftermath of such a mega disaster. A giant earthquake and tsumani should should have been planned for. I feel very bad for them, but this was poor planning on Japan's part.

A question that keeps occurring to me is whether or not a newer plant design would have fared any better. I've heard things about newer plants being capable of getting shut down with much less difficulty if necessary. It would be a real shame if a first generation plant kills safer nukes. Wind and solar just ain't gonna cut it - sorry environmentalists.

[Spheric Harlot]

Originally Posted by Big Mac 

It's somewhat amazing that with the large earthquakes Japan routinely has no one responsible for the nukes had the foresight to think about multi-stage contingency plans to cool the plants in the aftermath of such a mega disaster. A giant earthquake and tsumani should should have been planned for. I feel very bad for them, but this was poor planning on Japan's part.

I think what this makes clear is that, no matter how prepared, it's simply *impossible* to plan for every potential risk.

Nuclear power is safe, clean, and perpetual, until something happens that exceeded the limits of the imaginable.

[turtle777]

Originally Posted by Big Mac 

A question that keeps occurring to me is whether or not a newer plant design would have fared any better. I've heard things about newer plants being capable of getting shut down with much less difficulty if necessary. It would be a real shame if a first generation plant kills safer nukes. Wind and solar just ain't gonna cut it - sorry environmentalists.

Yes, newer plants they are safer.

http://online.wsj.com/article/SB10001424052748704893604576198421680697248.html

And you are exactly right, the US is a showcase how irrational fear of nukes killed safer plants.

-t

[Big Mac]

Originally Posted by Spheric Harlot 

I think what this makes clear is that, no matter how prepared, it's simply *impossible* to plan for every potential risk.

Nuclear power is safe, clean, and perpetual, until something happens that exceeded the limits of the imaginable.

Do you really think this disaster was beyond the limits of imagination? Because again, I don't think it was much of a stretch to imagine at all.

[Spheric Harlot]

8.25 Richter and 5m tsunami height apparently constituted the limits of the imagination at the time the plants were built.

[Laminar]

[The Final Dakar]

Jesus every morning I expect to see things are finally getting better and every morning they look like they're getting worse.

My hats off to the workers risking their lives to try and get this thing under control.

[The Final Dakar]

Understanding Japan's nuclear crisis

[subego]

Originally Posted by The Final Dakar 

Jesus every morning I expect to see things are finally getting better and every morning they look like they're getting worse.

My hats off to the workers risking their lives to try and get this thing under control.

Same here.

I imagine, like Chernobyl, some of these workers made the decision "I'm past the point of no return, better to have my life measured in weeks rather than swap me out and do the same to someone else.