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Japan Nuclear Plant Point of Failure


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The Japanese disaster represents an unprecedented triple whammy disaster. The earthquake, tsunami and nuclear issues now engulf the country. Although no significant new radiation has entered the USA, the situation in Japan remains fluid at the local level.

"We have somewhat prevented the situation from turning worse," Chief Cabinet Secretary Yukio Edano told reporters Sunday evening. "But the prospects are not improving in a straight line and we've expected twists and turns. The (radioactive) contaminated water is one of them and we'll continue to repair the damage." ... Source

What was the real point of failure?

Its looking like the main point of failure might not be the actual GE Mark 1 design at Japan's Fukushima Daiichi power plant. They appear to have largely withstood a 9.0-magnitude earthquake, a 30-foot tsunami, explosions, and fires. The main point of failure appears to have been the diesel generators.

Source: http://news.yahoo.com/s/csm/20110318/wl_csm/370818

"As to why the generators failed to withstand the earthquake and tsunami, Meshkati says that's a question for plant operator Tokyo Electric Power Co. (TEPCO) and the Japanese regulatory body. "Had the diesel generators worked, we wouldn

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A 45 ft tsunami is really tall and unexpected for Japan, that it is. I do think it should not have been built at sea level, but who knows, maybe all the nearby bluffs/highlands were taken up by something else... we do not know for sure.

I do agree, the diesel engines need to be put in a better container/core so that way they can work despite damage to the rest of the plant. Perhaps that is what they will be fixing next time =).

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TAO:

The disaster was a case where man said: "Failure is not a option", and mother nature said: "We'll see about that".

Hehe XD, yes, that it certainly was =). I think she likes to do that occasionally... after all, we are ruining her quite a bit with pollution and stuff. It's her way of saying back 'start respecting me'. :P

Best Wishes,

TAO

Edited by TAO
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Also, Japan will be no doubt a lesson for the rest of the world. When you compare and contrast the Japanese disaster with more recent disasters throughout the world, even Katrina, you see the incredible discipline that the Japanese people have. There is very little looting or lawlessness. Have you ever seen a people hits with such a disaster but are so composed?

No doubt. This incident will be reviewed and studied for as long as nuclear power is still an option, and will yield a whole host of recommendations and new regulations. From these recommendations, nuclear safety will be improved throughout the world. It seems that many people don't realize that the nuclear industry has one of the best safety track records ever, and it's partly because of the diligence that designers and regulators pay to past failures. It is too bad that we can't foresee all potential failures before they occur.

As a side note, while the generators may have been the primary failure in this whole event, investigations will certainly find numerous failures (mechanical, procedural, human, etc) any combination of which, if they had gone correctly, would have prevented or, at least, significantly reduced the damage caused. Three Mile Island had many "single-point failures" that, if they had not occurred, would have prevented the meltdown there.

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Most power plwants, nuclear or otherwise, pump through tremendous amounts of water for cooling. I mean a lot of water. That's why so many are located near oceans, bodies of water and large and fast flowing rivers - so the water dilutes and the temperatures don't rise from the hot water exiting the plants.

You'll never eliminate the risk when you build something. You can build to a 1/10,000 chance of failure standard or a 1/1,000,000 chance but there will always be a chance. There is a point where the waste of resources, effort and power to fight against possible disasters yields negative returns. It's easier to deal with the occasional inevitable destruction from freak natural disasters than it is to try and immune yourself and everyone else. Of course technology changes and eventually we might be able to do something more efficient than to build thicker walls. Maybe we'll build our coastal cities on giant life rafts that will auto-inflate and float whenever there is a massive flood or wave :P

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What oats said.

The specs were no doubt designed around certain safety factors and margins that were derived from empirical data. This tsunami/earthquake was such an outlier in that data (remember, the richter scale is logarithmic, meaning that 7 to 8 is ten times less than 8 to 9) that the safety factors and margins were just totally violated by the magnitude of the event.

Had the engineers and safety/assurance folks tried to convince the people forking over the money that they needed to widen the margin/increase the safety factor, it would have been deemed an imprudent use of money because Japan had never seen something like that happen before.

This sort of thing happens ALL THE TIME in government money + engineering projects. Not on this great a scale, to be sure, but there is *ALWAYS* a fight between engineers who want to ignore the money and do the best possible design (it's how we're trained) and project managers who try to maximize the product vs cost curve.

This is tragic and it sucks for Japan. I really hope and pray things turn out for the best.

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Mars:

True enough but we don't usually put metal spikes into the steering wheels of our cars for a reason. Not a good idea if we are involved in an accident.

With nuclear power it just may be that the cost of making them safe far exceeds the price tag of an accident.

Ps. Plutonium has just been found outside the plant. NOT GOOD. :P

Edited by thesometimesaint
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TSS: I've been wrestling with that thought quite a bit since Japan. This wasn't like Chernobyl or even 3 Mile Island. Those reactors were functioning nominally for 40 years (or so my brother who lives in Japan tells me) and this was an event that no one could have foreseen.

I'd like to think that it was something that could have been prevented. I'm normally a huge proponent of nuclear power, but this... man... this sucks.

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Mars:

Yes both those plants functioned differently. But the consequences of failure are just as dire.

When my solar water heater springs a leak. I clean up a little water mess. When a nuke plant springs a leak. Well lets just say I'd rather be a LONG ways away.

I'm neither a proponent or opponent of nuclear power. I personally would love to see the day when controlled nuclear fusion becomes a viable power source. The byproducts of nuclear fission however are deadly, and no plans exist for their safe disposal for the next quarter of a million years.

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That's not entirely true.

We can recycle spent fuel rods and make them re-fissionable. The process, when repeated, ends up shortening the half life considerably - down to the 200 yearish timeframe.

The main problem is that it's a verrrrrry difficult process and we are a little tied at the hands when it comes to diverting time, money, and resources to making it a less difficult/dangerous process. A lot of private industries who want to do it want subsidies to get their feet off the ground, and it's hard to convince the public to do this, for obvious and understandable reasons.

Solar power, I'll admit I'm not much of an expert (ha! i'm not even an expert on nukes, I just have an opinion that's only above "slightly informed.") but I do know that yes, absolutely, if your PV fails you have to get on the roof and replace it. I think and hope that we can manufacture the equipment to provide solar power on a consumer basis at a lower rate so that it doesn't take 50 or so years to pay off. If only there were a way to knock around more electrons with fewer photons...

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A networked solar array across everyone's home could substantially make an impact. The makeup from transmission line loss alone is an awesome benefit. The sun is strongest at the most expensive time of day to run your AC. No system/network overhead. It just needs to be cheaper and more efficient. I worked with an analog design engineer who showed me some numbers once and PVs are really making strides. "Almost there." :P

Wind power - totally agree. Far too intermittent.

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blackstrap, if I remember correctly, wind and solar are just about as cost-efficient as nuclear is - nuclear is a rather costly energy, due to the cost of building plants, getting dangerous material around, etc. However, the good thing about nuclear is that it has very little pollution effect in comparison to the others normally (except in rare situations like this). In addition, nuclear plants take up alot less space, which is another advantage. But nah solar power will be used alot more in the future I believe... I have heard of tiling that they can now lay across roof which costs about 10 cents/inch for an inch wide strand or so. Still pretty expensive, and I don't know how it does in weather, but it is a start on something which could truly help America's power problems.

I don't know if it's out yet though.

And then there's also that 'fuel-producing algae' that they are working on. That will be cool also... though imo, not as cool as the solar panels if we can get them working =).

Yah, wind power is intermittent unless you live in an area where it is pretty much guaranteed at a constant speed... there are places that have that, but it isn't ideal for all homes. I do hope solar works out though.

Best Wishes,

TAO

Edited by TAO
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Mars:

With nuclear power it just may be that the cost of making them safe far exceeds the price tag of an accident.

Ps. Plutonium has just been found outside the plant. NOT GOOD. :P

I'm surprised by this comment and by the attention the media is giving it. What do you all think the problem with this is? Plutonium is a by-product in all nuclear reactors. In fact, with regard to Mars' comment, plutonium is the primary reason the US has given up reprocessing, not because it's a terribly hard or dangerous process. As far as that goes--both France and Japan do it (So does North Korea...). The plutonium isn't inherently dangerous, either, it's a proliferation concern--it's supposedly easier to make a weapon out of plutonium than uranium (it's actually harder, but don't tell people that, they won't believe you--the real reason plutonium is such a concern is that it's easier to get than highly enriched uranium). Even with that, there are currently processes being developed that will enable spent fuel to be reprocessed without separating the plutonium from the uranium, which will eliminate the reason we don't do it here in the US.

As far as reprocessing changing the half-life, that is a misunderstanding. The primary benefit of reprocessing as far as the waste goes is the reduction in size and composition of the fuel. By pulling out the hotter waste, there is the potential to mix it with something stable so that it can be disposed of with less risk. It also lets the remaining material be disposed without all the unnecessary protection of highly radioactive waste. This means our high level waste facilities have smaller volumes of stuff to deal with and makes the whole process less expensive. Unfortunately, in our efforts to avoid proliferation and pollution issues, we've tied our hands and now instead of dealing with our spent fuel, we just let it sit there...

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I grew up on a farm where the electricity was provided by a windmill and a pile of batteries for storage. That was over 50 years ago. I currently live within 50 miles of 4 large wind farms.I probably could erect a windmill to power my home (except for a stove and a dryer),but it would cost over $20,000. I have a roof that is near perfect for installation of PV panels but in order to put up sufficient panels to power my place it would again take over $20,000

not counting inverters and switching mechanisms. The best way to save energy costs is to build homes that use less energy to heat , cool and light .And to retrofit current buildings. Perhaps then wind and solar can be used to supplement energy demands.

PS . my home is more energy efficient than 75% of the homes in the area.

PPS . we don't even want to talk about the massive demands for consistent and constant energy by industry and agriculture.Nuclear ,natural gas, and yes bad old Coal are the only viable choices for the foreseeable future.Stinks,doesn't it.

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Remember when they thought they discovered "cold fusion" at the U? Then it ended up a complete fail. (You know kinda like an anti-Mormon believing they have the "nail in the coffin" for the Lord's Church?) fool.gif Good times!

Here is the perfect scenario: an Israeli scientist makes cold fusion work and then we are completely independent of foreign oil, nuclear disasters and oil disasters in our waters. Then I am sure the world will start to love Israel right?

And btw plutonium-239 is very dangerous. Inhaling a few micrograms is very carcinogenic!

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mjr522:

Inside the reactor not so much. Outside BIG PROBLEMS.

Plutonium-239 is an isotope of plutonium. Plutonium-239 is the primary fissile isotope used for the production of nuclear weapons, although uranium-235 has also been used and is currently the secondary isotope. Plutonium-239 is also one of the three main isotopes demonstrated usable as fuel in nuclear reactors, along with uranium-235 and uranium-233. Plutonium-239 has a half-life of 24,200 years.

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Didn't the Libyans give Doctor Emmett Brown plutonium in exchange for him to build them a bomb, but instead he built the DeLorean Time Machine and gave them a fake bomb made up of pinball machine parts?

I think that's true history.

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And btw plutonium-239 is very dangerous. Inhaling a few micrograms is very carcinogenic!

Sure--all alpha emitters (helium ion that spontaneously break away from the nucleus) are carcinogenic when inhaled, and yes, Pu-239 has a relatively high decay rate compared to other alpha emitters. I guess my question with regard to the threat of the plutonium to humans is: what is the chance that someone is actually going to inhale enough Pu based on the small amounts found so far, that it will be a big concern? I recognize that there is probably a lot of plutonium present in these reactors (I don't know though, I'm not sure how long the fuel had been in service before this accident), but, again, I'm not sure I'm convinced yet that it is in a form (by which I mean that it's a molten pool at the bottom of the containment facility or a mound of solid stuff, not a gas or powder which would be required for inhaling large amounts of it) or concentration that presents any problem for people. More specifically, I wonder why is everyone making such a big deal about the plutonium when the fission products have the potential to do so much more harm.

With all that said, let me admit up front that I am not a health physicist, and I don't mind if one points out that I'm completely wrong.

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mjr522:

Inside the reactor not so much. Outside BIG PROBLEMS.

I don't completely disbelieve this statement. I'd just like to know what you see as being the big problem.

Plutonium-239 is an isotope of plutonium. Plutonium-239 is the primary fissile isotope used for the production of nuclear weapons, although uranium-235 has also been used and is currently the secondary isotope. Plutonium-239 is also one of the three main isotopes demonstrated usable as fuel in nuclear reactors, along with uranium-235 and uranium-233. Plutonium-239 has a half-life of 24,200 years.

Right. It doesn't seem to me that the facts that Pu-239 is used for making weapons or that it can be used as a fuel contribute the dangerousness of it being found outside of the reactor. Its half-life, while short compared to some alpha emitters, does appear to be long in our minds. But, a really long half life is a good thing when we are worried about the amount of radiation something produces--a shorter half-life means it produces a lot more radiation for a given mass in a given length of time. Additionally, since it is an alpha emitter, the primary danger it poses is for inhalation and ingestion--skin stops alpha radiation from doing any real damage. And, like I said previously, it doesn't seem that this Pu is in a configuration that would lend itself to ingestion or inhalation.

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