I'm thinking that the major issue is external load, and that's simply the grid that locally ceased to exist when the tsunami hit. You can't operate a 500+MW reactor without a matched load. If you'd defeat all safety features, the turbine would simply overspeed and disintegrate (read: explode).
So there: Chernobyl wasn't critical for any longer after things started to go wrong than TMI.
Now obviously hindsight is 20/20: in Japan nobody knew that things will be going downhill after SCRAM. I have no idea how well such things are modeled, and nobody has tried it out at full scale either, but it'd be really interesting to see how a GE's Mark I BWR would behave if it'd lose all cooling, with primary containment vented to the atmosphere, and the control rods kept out of the way. My hope is it'd bury itself without much ado. If anyone has some insight as to what might prevent that, I'm all ears. Seriously.
Sorry, but no. There are countries with legal systems fucked up enough, like Poland, where a mere timetable is subject to legal protections. In Poland you can't publish a frakking bus timetable without permission (haha) from the company that runs those buses. Same goes for any other timetable. Including TV programs methinks.
Nope. TMI scrammed soon after the turbine went into shutdown due to no water going to the steam generators. The whole incident took less than ten seconds, and what followed was due to previous fuckups and resulted in inadequate removal of decay heat, just like in Japan.
You know what? I'd have actually loved for the reactor never to scram, and to go into a LOCA and meltdown while critical. All of the shit would be probably half a mile underground by now (we're talking fuel that's hot enough to melt anything in its way). All those half-assed attempts at cooling, slowing down neutrons, etc. only mean that it will stay above ground where it's actually harmful. Meltdown by itself isn't anything bad. It's only bad when things are cool enough, but not quite. If you keep it under 1000K, you're good. If you can't -- don't bother, in fact do whatever you can to bring it above 4000K or so. Then it'll go down into the ground all by itself.
There is no such thing as "being contaminated by radiation", unless you're talking about neutron activation and that really only happens within a reactor. Stuff gets contaminated by other stuff that happens to fission and radiate. Neither alpha, beta nor gamma radiation can contaminate anything by itself.
So in all this talk of "radiation contamination", we need to know all of the following several things for it to have any fucking meaning in the first place: 1. What are the contaminating radionuclide(s), what are their proportions, and what are their half lives. 2. What kinds of radiation are released, and which ones are dangerous (if there's plenty of alpha but nothing else, you're fine as long as you don't eat it, for example, even if the level of alpha radiation is "whoa red zone"). 3. How easy are the contaminants to remove (some shit just washes with water, you know). 4. What was the mode of contamination, and thus what's contaminated (is it floating dust in the air, is it dust on the ground, is it food, water, what?).
The "readings" by themselves are useless unless you know all of the above.
You're certainly right to an extent. What you imply is a special event is in fact the daily bread and butter of keeping up a positioning system satellite constellation. The GPS system's frame of reference is being constantly kept in sync with Earth's rotation. After all, the satellites are simply orbiting the Earth in some arbitrary orbits, and the ground stations constantly monitor their orbits. The orbital data -- the ephemerides -- are broadcast to GPS receivers. The net effect of changing Earth's rotational speed or axis or whatever is simply a change in ephemerides -- they are Earth-relative, not Sun-relative. Any ephemeride updates are automatic, and -- if needed -- would have already happened.
This doesn't matter. The reactors have successfully SCRAMmed by automated systems, probably while the quake was still underway. Had they not SCRAMmed, without cooling they'd be dry in short order, and the core would've melted not soon thereafter. Hours, tops.
There's nothing earth-shattering about Asimo's playback-style technology. Heck, I'd consider it quite outdated by now. Ever heard of big dog, for example?
People problems are the same in power generation whether it's nuke or coal. You have the very same lapses in inspections and maintenance in both. The effects can be arguably just as disastrous. Coal ash sludge is toxic and it will pretty much permanently contaminate river- and lakebeds. Cleanup requires digging shit up, just like in a nuclear "spill": you remove the material and move it somewhere where the NIMBY crowd is thin enough. Kid you not. Never mind that coal ash is toxic due to heavy metal content, but it's also the worst kind of radioactive waste: volumunous low-level waste. High-level waste is relatively easy to handle, in comparison.
Forgot something: If Navy could get it right, why can't the utilities get it right? Are NUPOCs sprinked with fairy dust upon birth or somesuch? What you're saying is that there's no way to get correct people in those positions. Just go dig yourself a burrow...
You know what? I'd be perfectly happy to live literally next door to a spent fuel rod storage facility. You're free to live next to a coal ash pile.
To operate a coal-fired plant you maybe need an engineering degree, if that. Nuclear power plant operators (people, not companies) have to be licensed. Everyone makes mistakes, but to say that nuclear power plants are any more deadly is just silly. I'm sure coal ash is not a big revenue generator (until shit happens), whereas the word "nuclear" is politicized and everyone gets jittery if you as much as mention it.
The nuclear waste "problem" you refer to -- well, it never really was a problem in the first place. You must have never worked anywhere near any conventional power plant, because then you'd have known that no matter what the fuel (coal, oil, gas), the waste is a huge problem. Even with natural gas you have to install and maintain insane scrubbers to get the sulphur out. Everything dwindles when compared to coal ash problem, though. Spent fuel rods are concentrated, high- or mid-level waste that's quite limited in volume. When it comes to radioactive coal ash, everything is against you: the amounts are such that you can't store it while protected from the elements. When the wind blows, you get the dust everywhere. The rain leaches stuff out. If any sort of containment fails (say a layer of plastic liner underneath the pile), it's pretty much impossible to fix it -- good luck digging up a mountain of coal ash to replace the liner. The sheer amount of stuff makes it a fire-and-forget, get-it-right-the-first-time type of a deal. There is literally no money available to fix anything when it comes to leaking/disintegrating coal ash piles, and some of the old ones may collectively require billions USD worth of maintenance.
I was inaccurate here: what I should have meant by the "primary fission reaction" was a made up gobbledygook stand in for "reaction going at a rate that produces close to the rated power output". Control rods and whatever other SCRAM systems you have in a BWR will cut the heat output by a factor of magnitude, there's still plenty of neutrons to go around to keep things hot.
It's not about stricter regulations or standards, it's about good engineering. You can't regulate your way out of reality, so to speak. 60s happened to be a period of lousy engineering in both cars and nuclear reactors. Too bad, but that's how it was.
This particular design? Well, a single, localized failure can lead to a self-destruction due to loss of cooling. When I was looking at some pictures of a different Mark I installation over a decade ago, it would appear that you could take out that reactor by a single grenade, placed by the right electrical panelboard. Or by throwing about a dozen circuit breakers. This was still not entirely fatal, but required several manual actions to bring up backup cooling. If the control building where the operators reside collapsed due to a quake, you'd be pretty much guaranteed that all units at Fukushima would overheat and suffer steam explosions.
Cores were retracted? WTF? You mean they removed the fuel rods? From a "hot" reactor? In a day? By magic? Look, all they did, and all they could do, was to stop the chain reaction -- that's what a shutdown does. They inserted (not retracted) control rods to stop the chain reaction. This likely has happened during or very soon after the quake was over. This does not make the reactor magically stop producing heat! The reactor, after a shutdown, produces decay heat that may be a couple percent of normal full-power output. We're still talking about megawatts of heats. Without active cooling, the BWR in question will self-destruct, yes, even after a shutdown. The reporters fail to explain the basics to the public: that's not new.
Because it's immaterial. They would need to shut it down perhaps a week before cooling was lost. A BWR that has been shut down will generate enough heat to violently self-destruct for at least a day or two, and enough heat to sustain internal damage perhaps for a week, IIRC.
A nuclear reactor is not like your electric water kettle. There is NO off switch. Stopping the primary fission reaction by inserting the control/emergency rods does not stop heat generation. There's plenty of fissioning byproduct that will simply generate decay heat for days on end. This heat is significant, and you need to keep cooling the reactor for perhaps a week until the heat output is low enough. The reactor was shut down via control rods likely before cooling has stopped. Had it been running at nominal operating power without cooling, you'd have a steam explosion probably on a minute timescale.
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I'm thinking that the major issue is external load, and that's simply the grid that locally ceased to exist when the tsunami hit. You can't operate a 500+MW reactor without a matched load. If you'd defeat all safety features, the turbine would simply overspeed and disintegrate (read: explode).
So there: Chernobyl wasn't critical for any longer after things started to go wrong than TMI.
Now obviously hindsight is 20/20: in Japan nobody knew that things will be going downhill after SCRAM. I have no idea how well such things are modeled, and nobody has tried it out at full scale either, but it'd be really interesting to see how a GE's Mark I BWR would behave if it'd lose all cooling, with primary containment vented to the atmosphere, and the control rods kept out of the way. My hope is it'd bury itself without much ado. If anyone has some insight as to what might prevent that, I'm all ears. Seriously.
And the football team ;)
Sorry, but no. There are countries with legal systems fucked up enough, like Poland, where a mere timetable is subject to legal protections. In Poland you can't publish a frakking bus timetable without permission (haha) from the company that runs those buses. Same goes for any other timetable. Including TV programs methinks.
Nope. TMI scrammed soon after the turbine went into shutdown due to no water going to the steam generators. The whole incident took less than ten seconds, and what followed was due to previous fuckups and resulted in inadequate removal of decay heat, just like in Japan.
Was Chernobyl critical "long", though? I really wonder how long was it critical -- minutes, hours, days?
You know what? I'd have actually loved for the reactor never to scram, and to go into a LOCA and meltdown while critical. All of the shit would be probably half a mile underground by now (we're talking fuel that's hot enough to melt anything in its way). All those half-assed attempts at cooling, slowing down neutrons, etc. only mean that it will stay above ground where it's actually harmful. Meltdown by itself isn't anything bad. It's only bad when things are cool enough, but not quite. If you keep it under 1000K, you're good. If you can't -- don't bother, in fact do whatever you can to bring it above 4000K or so. Then it'll go down into the ground all by itself.
There is no such thing as "being contaminated by radiation", unless you're talking about neutron activation and that really only happens within a reactor. Stuff gets contaminated by other stuff that happens to fission and radiate. Neither alpha, beta nor gamma radiation can contaminate anything by itself.
So in all this talk of "radiation contamination", we need to know all of the following several things for it to have any fucking meaning in the first place:
1. What are the contaminating radionuclide(s), what are their proportions, and what are their half lives.
2. What kinds of radiation are released, and which ones are dangerous (if there's plenty of alpha but nothing else, you're fine as long as you don't eat it, for example, even if the level of alpha radiation is "whoa red zone").
3. How easy are the contaminants to remove (some shit just washes with water, you know).
4. What was the mode of contamination, and thus what's contaminated (is it floating dust in the air, is it dust on the ground, is it food, water, what?).
The "readings" by themselves are useless unless you know all of the above.
"yours", not "your's" -- tsk, tsk; and "actually" is redundant ;)
You're certainly right to an extent. What you imply is a special event is in fact the daily bread and butter of keeping up a positioning system satellite constellation. The GPS system's frame of reference is being constantly kept in sync with Earth's rotation. After all, the satellites are simply orbiting the Earth in some arbitrary orbits, and the ground stations constantly monitor their orbits. The orbital data -- the ephemerides -- are broadcast to GPS receivers. The net effect of changing Earth's rotational speed or axis or whatever is simply a change in ephemerides -- they are Earth-relative, not Sun-relative. Any ephemeride updates are automatic, and -- if needed -- would have already happened.
We got shifted by our own planet. Go figure.
This doesn't matter. The reactors have successfully SCRAMmed by automated systems, probably while the quake was still underway. Had they not SCRAMmed, without cooling they'd be dry in short order, and the core would've melted not soon thereafter. Hours, tops.
Yeah, because someone's nightmares are a good thing to "go by". The "footage" you refer to is fiction. That's all there's to it.
There's nothing earth-shattering about Asimo's playback-style technology. Heck, I'd consider it quite outdated by now. Ever heard of big dog, for example?
People problems are the same in power generation whether it's nuke or coal. You have the very same lapses in inspections and maintenance in both. The effects can be arguably just as disastrous. Coal ash sludge is toxic and it will pretty much permanently contaminate river- and lakebeds. Cleanup requires digging shit up, just like in a nuclear "spill": you remove the material and move it somewhere where the NIMBY crowd is thin enough. Kid you not. Never mind that coal ash is toxic due to heavy metal content, but it's also the worst kind of radioactive waste: volumunous low-level waste. High-level waste is relatively easy to handle, in comparison.
That's the critical failure point we're dealing with now, which makes this a design flaw IMO.
No shit, Sherlock ;)
Forgot something: If Navy could get it right, why can't the utilities get it right? Are NUPOCs sprinked with fairy dust upon birth or somesuch? What you're saying is that there's no way to get correct people in those positions. Just go dig yourself a burrow...
You know what? I'd be perfectly happy to live literally next door to a spent fuel rod storage facility. You're free to live next to a coal ash pile.
To operate a coal-fired plant you maybe need an engineering degree, if that. Nuclear power plant operators (people, not companies) have to be licensed. Everyone makes mistakes, but to say that nuclear power plants are any more deadly is just silly. I'm sure coal ash is not a big revenue generator (until shit happens), whereas the word "nuclear" is politicized and everyone gets jittery if you as much as mention it.
The nuclear waste "problem" you refer to -- well, it never really was a problem in the first place. You must have never worked anywhere near any conventional power plant, because then you'd have known that no matter what the fuel (coal, oil, gas), the waste is a huge problem. Even with natural gas you have to install and maintain insane scrubbers to get the sulphur out. Everything dwindles when compared to coal ash problem, though. Spent fuel rods are concentrated, high- or mid-level waste that's quite limited in volume. When it comes to radioactive coal ash, everything is against you: the amounts are such that you can't store it while protected from the elements. When the wind blows, you get the dust everywhere. The rain leaches stuff out. If any sort of containment fails (say a layer of plastic liner underneath the pile), it's pretty much impossible to fix it -- good luck digging up a mountain of coal ash to replace the liner. The sheer amount of stuff makes it a fire-and-forget, get-it-right-the-first-time type of a deal. There is literally no money available to fix anything when it comes to leaking/disintegrating coal ash piles, and some of the old ones may collectively require billions USD worth of maintenance.
Even the blinkenlights front panel from the Connection Machine ;)
I was inaccurate here: what I should have meant by the "primary fission reaction" was a made up gobbledygook stand in for "reaction going at a rate that produces close to the rated power output". Control rods and whatever other SCRAM systems you have in a BWR will cut the heat output by a factor of magnitude, there's still plenty of neutrons to go around to keep things hot.
It's not about stricter regulations or standards, it's about good engineering. You can't regulate your way out of reality, so to speak. 60s happened to be a period of lousy engineering in both cars and nuclear reactors. Too bad, but that's how it was.
This particular design? Well, a single, localized failure can lead to a self-destruction due to loss of cooling. When I was looking at some pictures of a different Mark I installation over a decade ago, it would appear that you could take out that reactor by a single grenade, placed by the right electrical panelboard. Or by throwing about a dozen circuit breakers. This was still not entirely fatal, but required several manual actions to bring up backup cooling. If the control building where the operators reside collapsed due to a quake, you'd be pretty much guaranteed that all units at Fukushima would overheat and suffer steam explosions.
Cores were retracted? WTF? You mean they removed the fuel rods? From a "hot" reactor? In a day? By magic? Look, all they did, and all they could do, was to stop the chain reaction -- that's what a shutdown does. They inserted (not retracted) control rods to stop the chain reaction. This likely has happened during or very soon after the quake was over. This does not make the reactor magically stop producing heat! The reactor, after a shutdown, produces decay heat that may be a couple percent of normal full-power output. We're still talking about megawatts of heats. Without active cooling, the BWR in question will self-destruct, yes, even after a shutdown. The reporters fail to explain the basics to the public: that's not new.
Because it's immaterial. They would need to shut it down perhaps a week before cooling was lost. A BWR that has been shut down will generate enough heat to violently self-destruct for at least a day or two, and enough heat to sustain internal damage perhaps for a week, IIRC.
A nuclear reactor is not like your electric water kettle. There is NO off switch. Stopping the primary fission reaction by inserting the control/emergency rods does not stop heat generation. There's plenty of fissioning byproduct that will simply generate decay heat for days on end. This heat is significant, and you need to keep cooling the reactor for perhaps a week until the heat output is low enough. The reactor was shut down via control rods likely before cooling has stopped. Had it been running at nominal operating power without cooling, you'd have a steam explosion probably on a minute timescale.