No. Mechanical failure followed by a large release of stored magnetic field energy.Joseph Chikva wrote:I do not know what here has been discussed but fast switching off of large inductance would damage some components of circuit (may be melt down because of self-induction). That's all.D Tibbets wrote:High density energy storage can and do fail spectacurly. As noted above. Superconducting magnets are an example of this . The large powerful super conducting magnets in the ITER tokamac could make an impressive explosion if the supetconducter quenches. Apparently there are safty measures - very quick switching through robust busses into a large heat sink (like a lake). This has been discussed on this board before. A Polywell with as strong but smaller superconducting magnets is to a degree less forbidding. I wonder if a quench in this case might do ~ the same amount of damage as did the failure of a magnet in the LHC a couple of years ago.
At LHC as I know (may be not correctly) as result of failure very powerful beam hit wall and burnt out the hole.
What would happen if an energy storage device failed?
Engineering is the art of making what you want from what you can get at a profit.
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Joseph Chikva
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Magnets are calculated on mechanical strength. If all correct in design - not damaged. In Russia 900MJ superconducting energy storage has been built: http://www.niiefa.spb.su/res/gif/101113.gif As I know this is largest ever builtMSimon wrote:No. Mechanical failure followed by a large release of stored magnetic field energy.
Largest capacitive energy storage as I know in Sandia Lab for Z-machine:
http://upload.wikimedia.org/wikipedia/e ... ine480.jpgThe Z machine at Sandia National Laboratory. Due to the extremely high voltage, the power feeding equipment is submerged in concentric chambers of 2 megalitres (2,000 m³) of transformer oil and 2.3 megalitres (2,300 m³) of deionized water, which act as insulators. Nevertheless, the electromagnetic pulse when the machine is discharged causes impressive lightning, referred to as a "flashover", which can be seen around many of the metallic objects in the room.
I understand that could happen if one quenched, but what would happen if a superconducting magnet at ITER shattered while fully charged?D Tibbets wrote:High density energy storage can and do fail spectacurly. As noted above. Superconducting magnets are an example of this . The large powerful super conducting magnets in the ITER tokamac could make an impressive explosion if the supetconducter quenches. Apparently there are safty measures - very quick switching through robust busses into a large heat sink (like a lake). This has been discussed on this board before. A Polywell with as strong but smaller superconducting magnets is to a degree less forbidding. I wonder if a quench in this case might do ~ the same amount of damage as did the failure of a magnet in the LHC a couple of years ago.
Lithium ion batteries can be a problem as illustrated by many notebook computer fires. A large lithium ion battery pack could be more impressive when it fails. Tesla Motors handles this by placing a few batteries in a resistant container, and then hooking a bunch of these sub assemblies together to run their roadster.
Dan Tibbets
The system wouldn't complete a circuit anymore, correct? Or would plasma generate to take the place of the "missing" superconductive material?
What would happen to the magnetic field? Would it just go stray somewhere and dissipate into the earth? Would it all instantly dissipate into whatever possible remnants of the circuit it was (previously) generated by?
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Joseph Chikva
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Do not consider so dramatic scenario, but consider that by some reasons superconducting condition stopped. Superconducting filaments are in the copper matrix. Copper will conduct that current with overheating. May be melt down. But I am sure that this scenario was simulated and cross section of matrix is big enough for avoiding meltdown.mdeminico wrote:but what would happen if a superconducting magnet at ITER shattered while fully charged?
ITER has three types of magnets:mdeminico wrote:What would happen to the magnetic field?
Central solenoid
Do not remember how many toroidal field coils
Do not remember how many poloidal field coils.
When people talk about big energy stored in the magnetic field of ITER (or any other TOKAMA) the talk is about toroidal field.
What would happen if one coil will failure?
Nothing dramatic. Uniformity of a magnetic field on an axis will be broken. Plasma confinement will be worse. Plasma will flow on the wall in that area being cooled there.
I have personally witnessed inductive kickbacks that have literally hammered high power switching components like IGBT's to the point where they fail catastrophically in a blast releasing the energy via plasma ball. The ones I have seen have been of sufficient energy to blow off the door of a locked down NEMA 4 can, and split open and eat material like dropping a rock from 4 feet into a bowl of tomatoe soup. This was done by a 100HP 3 phase motor collapsing its field back on to the inverter power pack with nowhere else to go. The fix was simple, a 100HP transistor tied to the DC bus, and set to dead short the bus to a large resistor when DC volts climbed above its bias point during the motor's field collapse backfeeding the invertor. Very effective and elegant solution. But the point is, large energy when not properly handled, seeks a violent solution to disappation.MSimon wrote:No. Mechanical failure followed by a large release of stored magnetic field energy.Joseph Chikva wrote:I do not know what here has been discussed but fast switching off of large inductance would damage some components of circuit (may be melt down because of self-induction). That's all.D Tibbets wrote:High density energy storage can and do fail spectacurly. As noted above. Superconducting magnets are an example of this . The large powerful super conducting magnets in the ITER tokamac could make an impressive explosion if the supetconducter quenches. Apparently there are safty measures - very quick switching through robust busses into a large heat sink (like a lake). This has been discussed on this board before. A Polywell with as strong but smaller superconducting magnets is to a degree less forbidding. I wonder if a quench in this case might do ~ the same amount of damage as did the failure of a magnet in the LHC a couple of years ago.
At LHC as I know (may be not correctly) as result of failure very powerful beam hit wall and burnt out the hole.
Ask any HV distribution guy whether or not it is a good idea to slow throw a pole or tower manual disconnect.
Ask any weaponeering dude how to take down high energy targets. The answer is normally simple and elegant, as well as effective, and involves using the target's energy against itself with a well placed "nudge".
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Joseph Chikva
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Some years ago I worked on an investigation of a building power distribution switch called a Bus-Duct. This was a fused disconnect for 3-phase, maybe 480 V, fused for 4000 A but running off a bus capable of 10,000. Three electricians were present when a tool shorted across two bus legs. The resulting explosion threw one of them through a steel door, killing him. I think the other two were badly burned. So even ordinary building power can produce explosions that rival hand grenades.
I've had plain old nicads get hot enough to start squealing when shorted. Any modern high-performance battery should generate some fear and respect. Some types can't be shipped by air any more. I would expect a fair body of cases involving electric and hybrid cars must exist by now ... they must be a handful of trouble during collisions.
Putting some internal impedance in an energy storage device should help reduce the rate of discharge. However, penetrating a battery would likely produce rapid discharge unless the chemistry itself limited the discharge rate. Depending on the mechanism, an ESD may not have a mechanism like basic chemistry rate equations to limit its discharge. I would expect a "super-cap" would discharge nearly instantly if penetrated by a conductor, with essentially all the energy ending up as heat one way or another. If that energy is up in the "pounds of TNT" range, an explosion would be hard to avoid.
But then again, how many of you have changed out the relief valve in your hot water heater recently? If one of those fails, then the thermostat, and the tank ruptures (happens more often than you would think), you can also get an explosion in the range of pounds of TNT. Or steam scalding accidents, ala Casey Jones.
I've had plain old nicads get hot enough to start squealing when shorted. Any modern high-performance battery should generate some fear and respect. Some types can't be shipped by air any more. I would expect a fair body of cases involving electric and hybrid cars must exist by now ... they must be a handful of trouble during collisions.
Putting some internal impedance in an energy storage device should help reduce the rate of discharge. However, penetrating a battery would likely produce rapid discharge unless the chemistry itself limited the discharge rate. Depending on the mechanism, an ESD may not have a mechanism like basic chemistry rate equations to limit its discharge. I would expect a "super-cap" would discharge nearly instantly if penetrated by a conductor, with essentially all the energy ending up as heat one way or another. If that energy is up in the "pounds of TNT" range, an explosion would be hard to avoid.
But then again, how many of you have changed out the relief valve in your hot water heater recently? If one of those fails, then the thermostat, and the tank ruptures (happens more often than you would think), you can also get an explosion in the range of pounds of TNT. Or steam scalding accidents, ala Casey Jones.
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Joseph Chikva
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Short circuit with low internal resistivity of voltage source would give more than projected current. Plus arc when tool shorted buses. I have at my home half-melted off flat-nose pliers. But people work with electricity including HV.Tom Ligon wrote:Some years ago I worked on an investigation of a building power distribution switch called a Bus-Duct. This was a fused disconnect for 3-phase, maybe 480 V, fused for 4000 A but running off a bus capable of 10,000. Three electricians were present when a tool shorted across two bus legs. The resulting explosion threw one of them through a steel door, killing him. I think the other two were badly burned. So even ordinary building power can produce explosions that rival hand grenades.
Concluding, first question was: will breakdown of 10 MJ capacitor have catastrophic aftereffects.
First of all 10 MJ is not one capacitor but number of many connected together in a rather big building. So, breakdown of 10 MJ at once is impossible. Breakdown of a single capacitor of a bank is allowed. Damaged capacitor then should be changed.
Reminds me of supercapacitor armor.Tom Ligon wrote:I would expect a "super-cap" would discharge nearly instantly if penetrated by a conductor, with essentially all the energy ending up as heat one way or another. If that energy is up in the "pounds of TNT" range, an explosion would be hard to avoid.
http://www.telegraph.co.uk/technology/n ... tists.html
Different mechanism though. I think they try for a transient, localized, high E-field, and avoid penetration of the capacitor entirely.
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Joseph Chikva
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I wouldn't be so sure it's impossible. The nth ionization energy of most elements is absurdly high as you get to double digits. If there were ever a way to physically separate those elements from the opposite polarity side, you could have some insanely powerful capacitors.Joseph Chikva wrote: Concluding, first question was: will breakdown of 10 MJ capacitor have catastrophic aftereffects.
First of all 10 MJ is not one capacitor but number of many connected together in a rather big building. So, breakdown of 10 MJ at once is impossible. Breakdown of a single capacitor of a bank is allowed. Damaged capacitor then should be changed.
Case in point, the 27th ionization energy of Nickel is just shy of 1 MJ/mol, and the 28th is over 1 MJ/mol. So only 59 grams of nickel could in theory store the 28th + 27th + 26th + ... + 2nd + 1st ionization energies, which is over 4 MJ.
Yeah but you can't BIP it in Times Squareladajo wrote: Ask any weaponeering dude how to take down high energy targets. The answer is normally simple and elegant, as well as effective, and involves using the target's energy against itself with a well placed "nudge".
And going back to my second question, imagine this scenario...
A toroidal SMES unit. Charged with a fairly high amount of power (let's just say 100MWh), to be used for grid energy load leveling.
Now, say an earthquake or something happens. The circuit in the coil of superconducting wire is interrupted.
What happens to the magnetic field? Where does it go? See all the questions in my previous question.
I called physicist Catherine Asaro once when one of her stories used a huge potential gradient to shield a space station. She was charging the station up to a huge positive potential (some billions of volts) by spewing electrons out, to repel positively-charged nuclei.
I pointed out that was all well and good, but anything that stopped the positive particles was gonna attract electrons like a sumbitch.
That kind of shield might mean the other side does not NEED a weapon.
I pointed out that was all well and good, but anything that stopped the positive particles was gonna attract electrons like a sumbitch.
That kind of shield might mean the other side does not NEED a weapon.