Cringley: Japan may have just permanently lost 20% of its electricity supply | Hacker News Reader

Cringley: Japan may have just permanently lost 20% of its electricity supply

cringely.com

254 pointstomfakes94 comments

Like they wouldn't have boron near a nuclear reactor. I'm a PWR man myself, but I am 99% sure that GE BWR designs have a couple of big tanks of borated water specifically for a LOCA. I highly doubt they're having reactivity problems, it's probably just managing the decay heat, and now the radiation leaks, that's the problem. "Just" is a relative word, here, of course.

Boiling water reactors are simpler, cheaper, but generally aren’t made anymore because they are perceived as being less safe. That’s because the exotic coolant in the pressurized water reactor can contain boric acid which absorbs neutrons and can help (or totally) control the nuclear reaction. You can’t use boric acid or any other soluble boron-laced neutron absorbers in a boiling water reactor because doing so would contaminate both the cooling system and the environment.

He's completely wrong about industry adoption of BWRs. There are two BWR's planned to be built in the US (along with 3 or 4 PWRs), and I believe that China has contracted with GE for a few as well (along with 4 Westinghouse PWRs and maybe a few Areva ones too).

PWRs are preferred largely because of their higher power densities (a BWR core that produces the same power must be larger) and simpler nuclear calculations and control strategies (two-phase flow makes calculations much more difficult, and it's harder to calculate correct positions for control blades (whose effects are highly localized) than it is to calculate the correct boron concentration (whose effects are smeared over the whole core)). However, now that computers are faster and us nuclear engineers no longer have the excuse of slow computers to hide behind, PWRs are looking to move away from relying on Boron concentration as the main form of control (the Westinghouse AP1000, specifically, relies much more on rod movement than the AP600), because of the cost of performing regular boron dilutions.

He's right that BWRs are simpler and cheaper - about half the moving parts.

Is one of the advantages of the BWR that you don't need a large pressure vessel? I remember news articles about JSW in Osaka being the only source for the huge forgings required for PWR pressure vessels, and only having the capacity for ~4 reactors per year.

Not really. BWRs need larger pressure vessels, PWRs need thicker ones.

I believe that JSW is the only place (also I think there's one in Germany, too) where you can forge a reactor pressure vessel in one piece, but that if you're willing to bolt two pieces together there are a few more options. It may be that this is more feasible for a BWR than a PWR, but I actually think that BWR pressure vessels are usually more expensive.

Where BWRs really save all the money is that you don't need to buy, maintain and replace pressurizers, steam generators, and a ton of piping and pumps that need to be rated for 2500 PSI, as well as a whole bunch of instrumentation for measuring and controlling boron dilution levels. You'll be paying more for engineering services, since all the calculations will take longer, but I can only imagine it's worth it, since, high-margin as engineering services are, they're chump change compared to how much the reactor costs.

I thought the new designs were classified as ALWRs - advanced light water reactors (light water meaning they use regular water).

However they're "classified", some of them (ABWR, ESBWR) work by boiling water inside the core at atmospheric pressure and using the steam to turn a turbine, and some of them (AP1000, EPR) work by heating pressurized (borated) water inside the core, which then transfers heat to other (pure) water at a steam generator, which (pure) steam is then used to turn a turbine.

> Like they wouldn't have boron near a nuclear reactor.

They probably do, the question is whether they can carry it to the site faster than the US navy, and whether the boron tanks have not been compromised.

The question is also, and I didn't make it clear enough in my original post:

"Wait, they need boron?"

Boron is a neutron absorber, and is therefore used to control the fission rate. You add boron when you're afraid of the fission rate getting out of control (e.g. Chernobyl). This is a legitimate concern here for two reasons:

1) A BWR is significantly more reactive (conducive to a high fission rate) at cold zero power than at hot full power, because cold water is a better neutron moderator than steam.

2) Xenon-135 and Samarium-149 are by-products of nuclear fission that have an effect on reactivity similar to boron. Their half-lives are on the order of hours, so when you crank down the fission rate, a couple hours later you also crank down the concentrations of Xe-135 and Sm-149, which, if you're not careful, can cause the reactor to go supercritical (and possibly prompt supercritical - a form of criticality in which everything happens approximately a thousand times faster - pretty much the worst-case reactivity excursion scenario) again a few hours after shutdown.

So, basically, you need enough negative reactivity from somewhere, either control rods or borated water, to counteract these two reactivity insertions. The Japanese reactor is almost certainly designed so that inserting all of the control rods into the core will kill any and all reactivity increases after shutdown.

What is most likely occurring is that there is very little nuclear fission inside the reactor right now. All the power inside the reactor is coming from decaying fission products, and it's probably on the order of kilowatts, it's just that the when the flow rate through the core drops from gallons per second to essentially nothing, a few kilowatts per cubic foot will get you pretty damn hot pretty damn quick. At this point some of the fuel rods have probably failed as well (if not melted), so the water in the reactor may be nastier than usual.

Unless the control rods have failed or are in the process of failing, I doubt that boron is even necessary for reactivity control, except as insurance. My educated guess is that their problems are entirely thermal- and containment-related, and that there is no danger of a reactivity accident, since a xenon transient or a condensation transient would have run its course by now, so the control rods probably have enough reactivity worth to keep the reactor subcritical indefinitely.

They don't want to control reactivity anymore, they likely want to kill the reactor core completely in order to not take any risks (not just to keep the core subcritical, but to avoid it simply melting as well, if the pumps did not work they don't have the waterflow they need, so the next option is to end the core fast). And for that, boron is the best tool.

Subcritical is "killed completely" from a nuclear standpoint - lowering the reactivity of an already subcritical reactor (e.g. adding neutron absorbers) does nothing but make the fission rate decrease faster. The fission rate already changes on short time scales, (e.g. orders of magnitude in minutes/hours during a scram). If the fission rate is already essentially zero, which it is in the Japanese reactor by now, it does nothing at all.

The heat inside the core is being produced by the decay of fission products, and there's absolutely nothing you can do to stop that except wait for enough half-lives that the activity slows down a bit.

Your general thesis, namely that as soon as they decide the reactor can't be salvaged, they'll dump in a bunch of boron just to be safe on the nuclear front, is correct, but where you're wrong is in assuming that adding a bunch of boron will help cool the reactor at all - it won't. All it will do is ensure that the reactor never goes critical again.

This is why spent fuel needs to sit in a pool of water for 5 years before anyone even considers moving it. Decay heat is serious shit, and it's not related to neutron physics at all.

EDIT: Probably time to get more specific about the term "reactivity". Reactivity is related to the "multiplication factor", which tells you how much bigger each generation of neutrons is than the last. It's zero when each subsequent generation is the same size - this is the normal operating state of a reactor, positive when each subsequent generation of neutrons is larger, and negative ... you get the idea.

If you've ever touched population dynamics in a differential equations class, you'll realize that this is a recipe for exponential growth and decay. Basically the time scale on which nuclear reactions proceed is "reactivity / mean neutron lifetime", with the caveat that if your reactivity is just above zero, neutron population growth is constrained by the longest-lived neutrons (it's like if every family has 2 kids, except for a couple hundredths of a percent, who have three, but put their third kids in cryostasis for a thousand years). In practice, this is how reactors are operated, because the mean neutron lifetime is _very_ small, so the worst thing that can happen is if your reactivity moves outside of this regime (this happened at Chernobyl). If your reactivity is negative, you are _always_ constrained by the longest-lived neutrons, but that's okay, because even this time scale is pretty short.

The upshot here is that if each successive generation of neutrons is smaller than the last, the number of neutrons (and hence things like fission rate that depend linearly on the number of neutrons) decays exponentially with a pretty short time constant.

The definition of "subcritical" is "having negative reactivity", so if the reactor is subcritical for any length of time, the fission rate will have exponentially decayed down to a tiny number.

Someone's under the impression that the US Navy is capable of doing whatever they want, whenever they want. In actuality, it took a very long time for US-Japanese relations to get to the point where the Navy would be able to station a nuclear-powered aircraft carrier, the USS George Washington, at the fleet activities base in Yokosuka. Prior to that, only the conventional carriers Midway, Independence and Kitty Hawk were allowed, and nuclear-powered carriers making a port of call were sometimes diverted due to tensions with the civilian population. Nuclear weapons themselves were banned and the forward carriers were weaponized at sea, in secret, from other vessels.

So, no, given the state of relations between the countries and the general lack of experience in civilian application, not to mention the improbability of possessing the resources, I'd highly doubt that the US Navy would be instrumental in assisting the qualified and experienced staff at a nuclear power plant located in a highly developed country such as Japan. I think the author was just throwing that in there to add some ominous weight to his argument.

So you are saying that Clinton lied? He was quoting Hillary Clinton, a source that should generally be above all suspicions.

The Bosnian airport shooting saga comes to mind. However in this case, there would seem to be little to be gained by fudging the issue.

Just an FYI, the additional reactors going in in South Texas are ABWR's, not BWR's.

I don't know much about nuclear reactors. To my untrained ear, what Cringely says sounds fairly reasonable. But then, having read a bunch of articles of his linked in the past on computer hardware and software, which I do know something about, I find that what he writes usually falls into one of two categories: (1) stuff that's obvious to anyone who knows what they're talking about and are paying any attention at all, and (2) crack-pot half-baked ideas that are laughable and completely wrong.

He's also lied about having a PhD. I wouldn't consider him a very trustworthy source. If he's saying something reasonable, someone else more credible has probably already said it.

Being anonymous just got sweeter.

he lied a number of years ago about what he'd supposedly done with wifi, a couple high-gain antennas and a corner reflector.

He has an article in which he gives an explanation of what happened at TMI in his own words. Being a nerd for this stuff and having read the report of the president's commission (which he claims to have been on) I was... shocked to say the least.

Its hard to imagine he was actually on the same committee as the people who wrote the report. His explanation had elements that mirrored the report. For instance, there was a particular warning light discussed in both. But what function the light served in the plant, its behavior during the crisis, the operators' response to it, or its overall role in the incident, on these Crigley was dead wrong.

I suspect he got assigned to the president's commission for political reasons, or because he was a 'public media personality,' but that he actually contributed nothing. He remembers an indicator light because he sat there dumbfounded in the meeting where the smart people on the committee discussed it. He then incorporated that into his incredibly child-like and incorrect mental model of what happened.

Suffice to say, regardless of his experience on the TMI president's commission, his understanding of nuclear power is even more comically incorrect than his understanding of computers.

Mark Stephens (the Bob Cringely we're talking about here) graduated from college in 1975 with a bachelor's in physics. The Three Mile Island report was sent to the president in 1979: http://www.pddoc.com/tmi2/kemeny/transmittal_letter.htm

It's not inconceivable that he was hired to dig up some facts.

Here's what you need to read instead of Cringley:

http://en.wikipedia.org/wiki/Boiling_Water_Reactor_Safety_Sy...

Combine that with these:

http://www.tepco.co.jp/en/press/corp-com/release/11031219-e....

http://www.tepco.co.jp/en/press/corp-com/release/11031220-e....

And you can see what's going on. Ignore everything else.

Uhm... the other units at Chernobyl re-entered service for a solid decade after that incident. (Only one of them lasted a decade. Unit 2 caught on fire in '91. Unit 1 was shut down in '96 and Unit 3 lasted until Dec '99.)

Cringley's prediction will be wrong. There are a lot of units at that station, two of which are ABWR cores. I would speculate that the majority of these units will return to service.

I think you're right but I give him credit for drawing attention to a big issue that everyone else is ignoring which is Japan's diminished production capacity (rather than focusing on the doomsday meltdown scenarios most of the media are fixated on).

Even if they return to service eventually there's going to be downtime. That's going to force Japan to use more fossil fuels which will drive up the price (even more). Add a spike in oil costs to the loss of japanese economic output and I think our modest economic recovery just hit a big snag.

This is absolutely true. It will take time to online the other units at the other plants that automatically shut down too. These things don't come up and down on a whim.

Oil isn't used to make electricity. The major options are nat gas and coal.

This disaster will likely drive DOWN oil prices since Japan will likely need less of it in the short term.

I'm sorry? Oil isn't used to make electricity

Oil is used in some types of power station, and the markets are already reacting to not only the increased demand, but due to the infrastructure damage in the north of the country, the fact it'll be harder than ever to get it delivered.

http://online.wsj.com/article/BT-CO-20110312-700945.html

I initially assumed that Japans energy gneration profile was similar to the US where it's almost all coal and LNG which is why I didn't think it would impact the oil market as much.

A bit of googling gave me this article which states that oil is actually more popular than coal. http://www.fepc.or.jp/english/energy_electricity/electric_po...

I still wonder if their demand will go up since a lot of the infrastructure is damaged and unusable. But if it does go up, chances are they'll need more fuel oil.

Small generators, like the kinds you use for emergency backup power, often run on oil.

My point was regarding large scale power plants that would have a major affect on the market. Still, it turns out that oil based power plants are far more popular than I knew earlier.

maybe not in Japan, but here in Hawaii, oil is used to make electricity.

A meltdown is also not a doomsday event - the main bad things that happen are that the reactor goes out of service and that you have to somehow scrape a bunch of nuclear reactor slag off the bottom of the containment vessel.

That goes for the nuclear reactors and the oil refineries. There will definitely be a slow down and that will mean more external sources will be needed short-term, right during summer, where oil prices skyrocket.

I think it may be some time before Japan is fully back up and running, so their energy usage may be lower for a while.

The BBC is reporting a pretty major explosion. The link has video of it.

http://www.bbc.co.uk/news/world-asia-pacific-12720219

While not apparently nuclear, it does seem pretty major. Could be interesting to see what the damage from it will turn out to be.

There will never be a nuclear explosion.... even a meltdown is not a nuclear explosion. Even chernobyl was not a nuclear explosion.

I was referring to an explosion that contained nuclear/radioactive material, not a nuclear explosion.

One of the interesting things about disaster recovery planning for nuclear power plants is that you count on (X) number of things to go wrong and figure out how the plant recovers gracefully. In Japan they've effectively had three things go wrong: earthquake, tsunami, and general infrastructure damage. Most disaster scenarios only cover a single event and TEPCO has a lot to deal with.

In a disaster scenario the first reactions are generally passive (dropping of control rods, changing where water flows) and then "all" that remains is to cool the decay heat. Aye, here's the rub: the cooling system is not a passive system. It requires power to drive the water pumps for the cooling system that siphons the heat away from the reactor vessel. After initiating reactor shutdown the most critical time period is the first little while as that is when there is the most heat. Too much heat and it'll damage the fuel, vessel, and/or the cooling system and can effectively damage the reactor enough so to prevent it from ever recovering (thus, meltdown).

The questions left to ask are to what degree the cooling systems (primary and backup) are working, and whether they've been powered consistently. With that bit of information alone we'd be able to make a pretty accurate estimate as to the state of the reactors in question. What is scary is that it would be really simple to say that all of those systems are working as expected and that there is nothing to worry about. Since that hasn't been said I'm of the opinion that there is definitely something to worry about.

These "three things" boil down to one thing (the earthquake) and its foreseeable impacts. I certainly hope the disaster planners wouldn't see these things as independent failures (and assess probabilities accordingly), but that kind of hubristic "we can calculate the probabilities of all failure modes" thinking is one of the reasons I'm not a big fan of nuclear.

but that kind of hubristic "we can calculate the probabilities of all failure modes" thinking is one of the reasons I'm not a big fan of nuclear.

Would you be more comfortable with "we can't estimate the probabilities of all failure modes"? I am sure that all engineers involved in planning the failure-handling systems know that those "calculations of probabilities" are only estimates based on some assumptions.

I think nuclear often gets bad press because you can measure and calculate a lot of risks to a much higher precision than in other industries. Like "x amount of radiation released" where x is actually a very small number but the fact that you can measure it and make an estimate as to how many cancer cases will be caused by it makes it scary, while people don't care much about the risks of, say, coal-mining because thats harder to measure/estimate.

Doesn't seem to extend beyond energy production. For instance, tell people all about the dangers in chicken mcnuggets, or smoking, or a sedentery lifestyle, and they don't get very excited at all. Even if you quote statistics.

Certainly they never go as far as voting against chicken farms.

Its got to be the theoretical nature of nuclear power generation that has something to do with it. Its invisible, unfathomable and secretive, so folks distrust it?

Chicken mcnuggets, tobacco smoke, and sedentery lifestyles are not members of the set of "things that can cause arable land to become permanently uninhabitable". Nuclear accidents are in that set and that is why the public is (rightly) concerned about them.

Nuclear accidents are not members of the set of "things that are at all likely to actually hurt you or anybody you know". Sedentary lifestyles and tobacco smoke are in that set, but they lack the novelty and sensationalism that gives nuclear accidents their cachet.

I think that people (self included) are generally more accepting of risk if it's control is within their own hands. Dying of tobacco related illnesses or obesity is mostly within my own control. Dying because a a nuclear reactor leak is pretty much 100% out of my control.

Even then, people's estimates of danger are crazy. A nuclear accident is far less likely to kill you than any number of other things that are outside your control. A drunk driver running into you, for example, or a natural gas explosion.

Arable land gets people excited? Really? I can't say I don't know anybody that gets excited over arable land, I know one guy, but he's a soil and water commissioner.

That's still too intellectual to make most folks even notice. California farmland is getting poisoned by selenium from groundwater wells, but not a lot of folks picketing about that.

They might not care all that much about the "arable" part, but I don't think the "permanently uninhabitable" part is too intellectual for the average person to grok.

>Hillary isn’t the kind of person to choose the wrong words

How has no one pointed out there was never any coolant delivered and Hilary Clinton did in fact misspeak? It renders this article a bit moot.

http://www.reuters.com/article/2011/03/11/japan-quake-nuclea... "US did NOT deliver coolant to Japan nuclear reactor"

"Ultimately, however, Japan did not need assistance from the United States but Clinton did not appear to have been updated before she made her public remarks."

...or the Japanese sourced the coolant themselves (which appears to be the case) and the article is correct.

I trust Japanese engineering more than Cringley predictions. Let's wait and see what the engineers do.

BREAKING NEWS: Pressure successfully released from Fukushima No. 1 reactor: agency - Kyodo

http://twitter.com/martyn_williams/statuses/4645894316531712...

-----

Govt says radioactive measurements near plant roughly doubled, confirming release of gas.

http://twitter.com/martyn_williams/statuses/4645969566958387...

“I trust Japanese engineering more than Cringley predictions.”

What does that even mean?

That Cringely is less reliable than Japanese manufactured / designed goods.

That doesn’t make any sense.

Why is that

While true, this reactor was built by General Electric in the late 1960s.

http://www.icjt.org/plants/uni/a/uni194a.html

He says "That’s why the experts didn’t expect it because they are still thinking of how the plant can be saved, but it can’t be."

I will accept that statement as true when it comes from a fact-finding mission by the Japanese nuclear authorities, not Cringely.

I think experts refers to “experts” on CNN or Fox. Here is the relevant passage in the text I think this refers to:

“‘Coolant?’ wondered aloud all the CNN and Fox News nuclear experts looking for a lede for their stories. ‘What is she talking about, coolant?’”

And what’s wrong with speculation? Seemed reasonable enough to me.

Speculation is fine, as long as you understand my suspicion of it.

Cringely says Japan lost 20% of its electricity supply. I say I wont believe that figure until I hear it from the Japanese nuclear authorities themselves.

Nuclear power is about 35-40% of Japan's grid, according to the what appears to be a site operated by Japanese authorities.

"At present, there are 52 commercial nuclear reactors in operation in Japan with a total generating capacity of 45,742 megawatts. Nuclear power supplies about 35% of Japan’s total electricity demand. It is expected that nuclear energy’s share in electricity generation will increase to more than 40% by around 2010."[1]

[1] http://www.japannuclear.com/files/Japan%20Nuclear%20Fuel%20C...

Right or wrong it did a better job of explaining how coolant works in nuclear reactors and how they would usually shut down than anything I have seen on the news.

He shows technical understanding of the issue, but the alarmist tone of the article places it in the "pessimistic, under-informed opinion about the impact of a natural disaster" category.

Nevertheless, I'm waiting for the official verdict.

However the events unfold I wonder if this will cause more nations to investigate other reactor technologies like Thorium. The abundance of Thorium and its inherent safety mechanisms (as a liquid at least) make the technology very exciting.

Check out the Google Tech Talk http://www.youtube.com/watch?v=AZR0UKxNPh8

Hmm. Here in Central Europe this would probably read:

"However the events unfold we can rest reassured that scientists have to acknowledge that any use of nuclear technology for electrical power generation is inherently unsafe and therefore irresponsible."

And then we build a new coal power plant.

Not even probably. In Germany, opposition parties already (and once again) demanded of the government to rethink their nuclear strategy. (No new nuclear power plants are built or planned in Germany but the coalition government recently extended the runtime of existing nuclear power plants.)

I'm a bit annoyed that the only two options in Germany seem to be to either shut all nuclear power plants down or to extend the runtime of the already existing and rather old nuclear power plants. It seems to me that it is possible to have safer nuclear power but no political party in Germany seems to be willing to even talk about that.

It is worth mentioning that France is still big on nuclear and we will likely be buying French power from nuclear plants.

FUKUSHIMA DAIICHI-1 was already scheduled to be shutdown this month.

http://www.icjt.org/plants/uni/a/uni194a.html

neutronicus has even more reasons why what Bob says is very likely wrong.

I suspect the decision to use sea water to cool the reactor means that they have decided to write off the plant. It was 40 years old anyway and nearing the end of it's service life.

the end of its service life was this month!

http://www.icjt.org/plants/uni/a/uni194a.html

Wondered when someone would mention that. Had seen the link to it in the comments on the Cringely article, posted by a Cringely sceptic. Weird coincidence that it happen the month it was due to be decommissioned.

CNN reports explosion at one of the plants.

http://www.cnn.com/2011/WORLD/asiapcf/03/12/japan.nuclear/

I find it notable that you have mounting pressure that could risk the integrity of the pressure vessel, yet can't turn a turbine connected to a pump to drive cool water through heat exchangers... If a reactor self-destructs unless you can cool it down actively after an emergency shutdown, there must be some serious design issues there.

After you completely kill the fission, you still have some heat being generated from the decay of fission byproducts doesn't sound weird that the device has enough power to self destruct but not enough to cool itself down?

The Fukushima plant produces 4.7GW: http://en.wikipedia.org/wiki/Fukushima_I_Nuclear_Power_Plant

The total nuclear production of energy in Japan is 47GW: http://en.wikipedia.org/wiki/Nuclear_power_by_country

Nuclear is 28.9% of Japan's energy source (same Wikipedia-article as above).

It doesn't add up. Where does the number 20% come from? 2% is closer to the truth.

http://en.wikipedia.org/wiki/Robert_X._Cringely

Robert X. Cringely is the pen name of both technology journalist Mark Stephens and a string of writers for a column in InfoWorld, the one-time weekly computer trade newspaper published by IDG.

I think that, currently, Cringely is just Stephens.

let's just hope a loss of power supply is everything they have to worry about. it seems some caesium already got out.

Can they not simply ship in extra batteries, or are they batteries too large to be moved?

(insert bad joke about non-user-replacable iNuke battery here)

I rather suspect the batteries are not easily replaced - they're a tertiary system, designed to be a short-term stopgap to get your primary and secondary systems back online. I'm sure that if just cycling batteries was an option, and the battery systems are operational, they'd do that - it's a heck of a lot cheaper than pulling the killswitch on the whole plant.

The batteries may also be someplace a workman really doesn't want to go.

I'm sure the Japanese have robots capable of it, they are the best in the world at that.

Well not any robot will do in high radiation environment, since radiation tends to fry their circuits...

They tried it in Chernobyl but it didn't really work, so they had to use humans to do it. Every soldier got to run in, move an item, run out and be dismissed from this nuclear cleanup duty, due to irradiation received in this one try.

I would expect robots in Japan in 2011 to be able to withstand a bit more than robots in the USSR in 1986.

They could probably fly or ship or truck in some smallish diesel generators to accomplish the same thing -- they're just pumps, so I find it hard to believe any individual load is bigger than your average transportable diesel genset. It shouldn't be too difficult to divide a load connected hydraulically vs. electrically across a bunch of generators quickly (switchgear is otherwise fairly custom).

The backup diesel generator at Oconee Nuclear Station (Oconee, SC) is fashioned out of a pair of modified diesel train engines ... it isn't exactly a simple "throw more power at it" problem. Even if it were trivially possible to add power as if you were filling up a tank of gas the bigger problem would be mating the power output and frequency of these generators with the rated values for the plant's electric system (on the fly, in an increased radiation environment, under high stress, with damaged basic infrastructure).

The people on the ground do not have an easy task in front of them.

the generators in question are used to run pumps. you wouldn't need to phase match them to the plant's electric system, per se. (you would need to phase match them to the other generators, but that is straight-forward)

Well. The datacenter across the street from my office has backup batteries which weigh in at half a ton apiece. Arranged in groups of eight.

And I'm betting they're positively puny compared to what you'd want for a nuclear plant's cooling system, so simply "shipping in" some extras may not be all that feasible...

I'm sure they are large; I was thinking mostly that as 20% of Japan's energy and a nuclear reactor are on the line, they'd be able to move many tons of batteries. Also remember, modern cars weight 1.5-2 tons, and are carried in sets of 8-10 cross-country by truck.

If your goal is to provide electricity, you would ship in generators and diesel (, gas, etc). Batteries are useful because you can store the energy being generated onsite, but their energy to weight ratio is an order of magnitude smaller than combustible fuels.

http://en.wikipedia.org/wiki/Energy_density

I guess the obvious question is whether 80% of electricity supply meets demand, probably not, how can Japan generate the additional 20% in a hurry?

Demand may be lower for quite a while, due to the same events that caused disruption.

Losing a plant means you lose a percentage of your peak capacity but not necessarily that you won't be able to provide the total amount of energy demanded by the economy. You could potentially move a portion of the usage to off-peak hours, starting with some industrial loads for example, moving a few factory shifts to the night.

Japan probably won't need that 20% for a while. Their demand just dropped significantly.

Not wanting to change the topic. But why on earth would you even consider nuclear power generation when you are in such a geologically unstable area? Sounds like idiocy to me. Fingers crossed here, could do without another man made disaster.

Why is this getting downvoted? It was the first thing that came to my mind too. Not only is the country prone to earthquakes, but as I understand, several of their power stations are built right on the east coast.

It's possible to make a building like a skyscraper fairly earthquake proof, but is it really possible to make things like nuclear power stations earthquake proof? Assuming the building is made to 'wobble', wouldn't that wreak havoc on the cooling systems and other gear inside?

Yes. It is possible:

http://www.world-nuclear.org/info/inf18.html

It's not like they don't think of this stuff ahead of time. This was planned for.

Because you need power and nuclear is the best way? Consider the facts:

1. The reactors in question here are now two technological generations old; they are old, fragile designs compared to more modern designs. 2. Japan just experienced one of the biggest earthquakes in world history, followed by a tsunami of a scope that makes Kurosawa's war scenes look like moving Legos around. 3. Despite this, there have been no catastrophic reactor failures. Zero. We're not out of the woods yet, but the smart money is on there being a couple minor incidents and no major incidents as a result of all this.

I'd say the decision to build nuclear plants instead of, say, dozens and dozens of coal plants (which would have killed a lot of people by now with their pollution) is looking pretty smart.

Probably won't have one -it's dangerous territory, but they are managing it. The Japanese are good at managing things, right? (right?)

They have a mix of nuclear, hydro, and other power generating systems to meet their energy needs. Nuclear is one of the cleanest and least disruptive to the environment.

Not sure about nuclear being the greenest, when you take into account mining for ore.

I appreciate these were exceptional circumstances. But to be confronted with a nuclear disaster of any proportion is horrifying. Then it becomes an environmental catastrophe.

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