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Self-Healing Ceramics for Nuclear Safety

timothy posted more than 6 years ago | from the now-with-fewer-pulsating-tumors dept.

Power 45

Roland Piquepaille writes "Pacific Northwest National Laboratory (PNNL) researchers have used supercomputers to simulate how common ceramics could repair themselves after radiation-induced damages. This is an important discovery because 'materials that can resist radiation damage are needed to expand the use of nuclear energy.' These ceramics, which are able to handle high radiation doses, could improve the durability of nuclear power plants. They also might help to solve the problem of nuclear waste storage. But read more for additional references about how this research could improve nuclear safety."

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45 comments

FIRST POST! (-1, Offtopic)

Anonymous Coward | more than 6 years ago | (#23131962)

FIRST POST!

Now if I could get some of that (3, Funny)

Chabil Ha' (875116) | more than 6 years ago | (#23131968)

To replace the pottery my kids accidentally smash...

Re:Now if I could get some of that (2, Funny)

creimer (824291) | more than 6 years ago | (#23132390)

Radioactive kids and ordinary ceramics just don't go together.

Pretty Helpful (1)

Protonk (599901) | more than 6 years ago | (#23132038)

Helpful, but more so for disposal of nuclear waste than for nuclear plants. IIRC, most of the critical components that would see very high radiation over their lifetime have to be metal or plastic for other reasons. If a good portion of those pieces could be replaced by ceramics in all respects, this would be a great advance.

For disposal and vitrification this would be a great advance. A huge element of uncertainty in the Yucca mountain facility comes from the caskets the waste is stored in. Ceramics would be more corrosion resistant than stainless steel and a 'self-healing' property would allow them to avoid becoming too brittle. Brittleness might be a key problem in long term storage like that. It would be interesting to see if the materials used in vitrification could take advantage of this. That's kind of a solved problem but it would be cool to change things up.

An interesting thing to see would be to watch how the material handles swelling. In a lot of cases, changes in dimensions is MUCH more important (in the long term) than other changes (to materials like poly-eurethane, steel, glass, not rubber or other plastics). I can see cracks and what not being fixed, but how about interstitial pockets being formed? Or gas evolution/absorption? Anyone have any information on that?

Re:Pretty Helpful (1, Interesting)

Anonymous Coward | more than 6 years ago | (#23132172)

I think it'd probably be more useful in plant operation than storage just because the fatigue mechanics are going to always be an unknown. When you're looking at a 10k year life span for some container it doesn't make much sense to use ceramics for anything structural. Like the actual container. Honestly, we should probably just burn all the fuel down even if Plutonium is a by product, and then just store the much smaller more inert waste left over. At least with a ceramic part in a plant you could get perhaps improved wear resistance, life, corrosian resistance, and monitor it, and perhaps saving on zirconium and weight should that prove important. When looking at long term storage the monitoring isn't going to be an option. Ceramics are brittle, they *will* crumble (smaller chips are stronger which has to do with certain statistical aspects of fracter mechanics. smaller pieces smaller largest cracks.) Ceramics are good at being chemically inert and hard. Sticking in one piece not so much. Steel (maybe not so much with hydrogen embrittlement), and especially bronze... well those will do a pretty good job of not crumbling.

You could probably sinter the ceramics in such a way that they were particularly porus, then perhaps coat them in teflon to confer some water resistance. Gas escapes, water generally stays out. But then you're really just using ceramics to protect the vessal and be chemically inert. (But you'd have the additional problem of accumulating water between your metal vessal and the ceramic defense, and possible catalytic reactions.

Re:Pretty Helpful (1)

vrmlguy (120854) | more than 6 years ago | (#23134264)

When you're looking at a 10k year life span for some container it doesn't make much sense to use ceramics for anything structural. Like the actual container.
Yeah, because concrete doesn't have much endurance. http://science.slashdot.org/article.pl?sid=06/12/01/170200 [slashdot.org]

Re:Pretty Helpful (1)

Protonk (599901) | more than 6 years ago | (#23134468)

concrete =/= ceramics. But, concrete IS interesting as hell. There was a time when concrete manufacturers in the midwest used old cherry pits as the aglomerate (instead of rocks and pebbles), because they were next store to a maraschino canning plant. they built a bunch of buildings and what not....until the pits sprouted and broke the concrete open. No one figured out that crushing the pits would be a good idea. :)

Re:Pretty Helpful (1)

vrmlguy (120854) | more than 6 years ago | (#23135278)

Since cement is a type of ceramic ("the term covers inorganic non metallic materials which are formed by the action of heat. Up until the 1950s or so, the most important of these were the traditional clays, made into pottery, bricks, tiles and the like, along with cements and glass. [wikipedia.org] "), and concrete is cement with an added aggregate, I'd say that the terms can overlap quite a bit. The use of ceramics for nuclear waste storage implies the use of the waste as an aggregate, making the final product a type of concrete.

Homer Simpson is be used in this as he is able to (-1, Offtopic)

Joe The Dragon (967727) | more than 6 years ago | (#23132150)

Homer Simpson is be used in this as he is able to eat nuclear waste and not die from it. There are useing his DNA as well.

Gads, I will be happy when the IFR comes (1)

WindBourne (631190) | more than 6 years ago | (#23132482)

I am sick and tired of all the issues about super long-term storage. Far better AND cheaper to burn this up over a 100 years, then to pay the monster price of 10000 years of storage, and all the concern about it. OTH, these ceramics certainly sounds interesting.

Re:Gads, I will be happy when the IFR comes (1, Informative)

polar red (215081) | more than 6 years ago | (#23133512)

burning up nuclear waste ???? That just spreads the radiation into the air

Re:Gads, I will be happy when the IFR comes (2, Informative)

SDF-7 (556604) | more than 6 years ago | (#23134284)

No, breeder reactors (or high burnup fuel) not literal combustion. See http://en.wikipedia.org/wiki/Burnup [wikipedia.org] .

Waste storage? (4, Insightful)

momerath2003 (606823) | more than 6 years ago | (#23132494)

The only problem with nuclear waste storage is politicians. Radioactive waste storage is a proven, safe technology. Even so, long-term geological storage is not the right solution, since we would be throwing away a lot of good, fissionable material that can be recycled for energy production in, e.g., fast reactors.

Re:Waste storage? (1)

Protonk (599901) | more than 6 years ago | (#23132716)

The only problem with nuclear waste storage is politicians. Radioactive waste storage is a proven, safe technology. Even so, long-term geological storage is not the right solution, since we would be throwing away a lot of good, fissionable material that can be recycled for energy production in, e.g., fast reactors.
In a sense. In another sense, it isn't true. If you act like a true environmentalist and have a discount factor of zero (future generations are worth just as much to you as current generations), then it IS still a problem. Deaths due to groundwater leakage 1500 years from now would deter you from using a potentially unsafe storage facility.

However, I don't understand why people are willing to damage the next generation while espousing concern for someone 10 generations from now. Global Warming will displace and impact millions of people within 100 years. Nuclear power represents a way to lessen that impact. how in the WORLD is that more important to these guys?

Re:Waste storage? (3, Insightful)

Chandon Seldon (43083) | more than 6 years ago | (#23132808)

If you get your fuel recycling going properly, then the cycle-end waste gets back to ore-level radioactivity in a couple hundred years. We have building technology that can reliably be trusted to store stuff for a couple hundred years - poured cement anywhere that isn't in a flood zone or on a tectonic fault line.

It's only with this damn fool "recycling nuclear fuel gives the terrorists nuclear bombs" nonsense that we're stuck with dangerously radioactive material 1500 years from now.

Re:Waste storage? (1)

Megane (129182) | more than 6 years ago | (#23133044)

It's only with this damn fool "recycling nuclear fuel gives the terrorists nuclear bombs" nonsense that we're stuck with dangerously radioactive material 1500 years from now.

And we have none other than James Earl "Misery Index" Carter Jr. [wikipedia.org] to thank for that.

Re:Waste storage? (1)

WindBourne (631190) | more than 6 years ago | (#23133646)

And yet, that was one of his very few bad decisions. All in all, the man had to do SHITLOADS of crap because nixon and ford had not. Both Nixon and Ford ignored the root of our MISERY problem and heaped loads of new regulations on. It was Carter who pushed oil and gas deregulation through to be applied in 1981. Nearly ALL of the inflation issue could be traced right back to republican choices. He even pushed airline deregulation which created the aviation boom that America, followed by the rest of the world saw. All in all, he like Poppa bush, followed idiots who had set America to fail down the road and made hard choices that cost them their 2'nd terms.

THe bitch is, that the next president will no doubt be accused of the same. They will HAVE to roll back W's tax cuts (which you republicans will call a tax increase) and cut spending. The republicans have again driven America into a nightmare path. Hopefully, the dems and indies will have enough common sense to push through a balanced budget amendment along with a rollback of the patriot act. Sadly, I doubt that they will do either.

2'ndly, while Carter did come out against breeder reactor, it was not a law. It was a presidential order. It was countermanded by Poppa Bush and the IFR WAS started. Clinton killed it, though he did not want to. Clinton did it as part of a deal. If you really want to blame anybody for preventing us from having an IFR, then blame Kerry. He pushed to kill it for the same reason that Carter did his order; fear of access to plutonium. Clinton killed it as part of a deal, but had actually fought that.

Re:Waste storage? (1)

Pinky's Brain (1158667) | more than 6 years ago | (#23133508)

The fact fast breeder reactors just haven't proven as safe as water moderated reactors probably has something to do with it as well.

There are coolants they can use for fast breeder reactors which don't result in a giant cluster fuck in worst case scenarios (lead and salt) but for the moment all the money and time has been put into liquid sodium ... which I wouldn't want in my backyard, or upwind in a couple 1000 km range.

Re:Waste storage? (1)

BlueParrot (965239) | more than 6 years ago | (#23133630)

Sodium has a couple of major advantages actually.

For starters it is FAR less corrosive to steel than is water, lead or molten salt. Now since I suspect Monju will be mentioned again, yes a sodium fire can MELT the steel ( this is what happened at monju ), but in terms of chemical corrosion sodium is second only to helium. As per the Monju accident you're not going to have me believe the same accident would have been a non-issue had it used lead instead. Sure, the lead may have caused less damage to the steel structures, but I seem to recall that airborne lead is not a particularly pleasant substance, and especially not after intense neutron radiation which gives rise to Po-210 ( yes , it is lower in pure lead than lead-bismuth, but the amount that is emitted to the air is also increased since the lead will necessarily be maintained at higher temperatures).

Sodium has excellent thermal conductivity and quite a decent heat capacity, which means natural convection will be greatly improved. It also has a relatively large volume change when heated, which further aids heat removal through natural convection.

Since sodium is much lighter than lead it doesn't cause as much stress on the equipment. Since lead has a density of 11, even a modest system height of 10 meters would give rise to a coolant pressure of 110 atmospheres at the bottom of the system

Unlike lead, sodium doesn't produce any long lived activation products under neutron activation. In contrast, lead will produce Pb-205 with a halflife of 1.53×10^7 years.

Because lead and salts have much higher melting points than sodium ( 97C for Sodium , 327 C for lead, 300C-500C for most molten salts considered ) it is a lot easier to prevent coolant solidification in a sodium cooled system. This is important since accidental "overcooling" could cause solidified coolant from the heat exchangers to clog up the system, causing local hot-spots in the core. Lead-Bismuth eutectic has a lower melting point than pure lead, but in return it is also much more corrosive, and more Polonium-210 is formed as it is irradiated.

Perhaps most important, however, is that sodium technology is compatible with zirconium-metal fuel. In contrast both lead and molten salts dissolve zirconium, so if the fuel is to be bound to the cladding by small layer of coolant ( and you want this to ensure adequate heat conductivity ) lead or salt cooled reactors would have to use ceramic fuels. Eitehr nitrides, oxides or carbides. Ceramic fuels do not only have poorer heat conductivities than metal fuels, they are also more difficult to reprocess , and they tend to form Carbon-14 from neutron capture ( this is especially true for nitride fuel, the fuel of choice for lead cooled systems, which would likely have to be isotropically enriched in order to prevent excessive C-14 formation ). Finally metal fuel is much easier to produce remotely than is ceramics, you just cast it.

Basically lead/salt has two huge advantages over sodium. Higher boiling points and lower reactivity with water and air (and transparency in the case of salt). In all other respects, however, sodium beat them hands down. Not even the lower neutron cross section of lead is much help due to the limited flow speed from corrosion concerns, which in practice means you need more lead in the core, thus countering the advantages from lower cross sections.

Re:Waste storage? (1)

BlueParrot (965239) | more than 6 years ago | (#23133682)

Since sodium is much lighter than lead it doesn't cause as much stress on the equipment. Since lead has a density of 11, even a modest system height of 10 meters would give rise to a coolant pressure of 110 atmospheres at the bottom of the system


That is of course supposed to be 11 atmospheres. Typos always happen at the worst place...

Re:Waste storage? (1)

vrmlguy (120854) | more than 6 years ago | (#23134286)

That is of course supposed to be 11 atmospheres. Typos always happen at the worst place...
If only Slashdot offered some way to view a message before actually posting it.

Re:Waste storage? (1)

Pinky's Brain (1158667) | more than 6 years ago | (#23133788)

I didn't say it doesn't have advantages, I'm sure it has major advantages ... most of them economic. What it doesn't have and never will have is as low a probability of meltdown as water moderated reactors or as low a severity of the results in the case of such a melt down. (This is usually disingenuously ignored when arguing for fast breeder reactors.)

As for Pollonium in the lead ... could you give me some numbers? The probabilities of complete exposure of the primary coolants in the first place for both types of reactors and the differences in environmental impact between partial vaporization of the lead and near full burn up of the sodium.

Re:Waste storage? (1)

BlueParrot (965239) | more than 6 years ago | (#23133866)

I didn't say it doesn't have advantages, I'm sure it has major advantages ... most of them economic. What it doesn't have and never will have is as low a probability of meltdown as water moderated reactors or as low a severity of the results in the case of such a melt down.


Uhm, they already do. Sodium cooled reactors have demonstrated that they are able to safely shutdown even with complete loss of control over their instruments, failure of all cooling pumps, and simultaneous failure of all control rods. The core simply heats up and expands until it is no longer able to sustain the chain reaction, at which point the decay heat from the radioactive fuel is dissipated from natural convection that is aided by the much greater heat conductivity of sodium. In contrast many existing PWRs would eventually melt down due to the decay-heat from fission products if forced circulation of the coolant was lost.

Furthermore, if the core would somehow melt ( say you somehow actually manage to block the coolant from circulating ) then the sodium cooled reactor is at essentially atmospheric pressure, while the water cooled designs would likely have to vent primary coolant to prevent pressure buildup. Sodium is also better at retaining fission products, as they dissolve in the liquid metal.

As for Pollonium in the lead ... could you give me some numbers? The probabilities of complete exposure of the primary coolants in the first place for both types of reactors and the differences in environmental impact between partial vaporization of the lead and near full burn up of the sodium.


Uhm, you don't have two types of reactors, you have perhaps hundred or so proposed designs for each type. I guess the most sane comparison for western reactors at the moment would be to compare ELSY ( European Lead Cooled System ) with the Advanced Burner Reactor , suggested in the US. The systems have essentially the same base design ( big primary coolant pool , heat exchangers for secondary coolant inside the primary vessel ). See http://www.gnep.energy.gov/images/advancedBurnerReactorWeb.jpg [energy.gov] , the big green pipes are the heat exchangers hanging inside the pressure vessel ( dark blue ).

I dunno which is more likely to leak really. Sodium has a higher vapor pressure for the same temperature (i.e lower boiling point ), but lead is more corrosive and puts more stress on the reactor vessel. In either case a leak would be very bad ( and a PR disaster ) , but unlikely to compromise the containment structure, so I'd say it is mainly an issue of which is more likely to leak to begin with.

Re:Waste storage? (1)

Pinky's Brain (1158667) | more than 6 years ago | (#23134126)

The only likely way to break a containment dome is with shrapnel from an explosion. Whether or not that is likely enough to worry about with liquid sodium, meh ... if all I have to go on are instincts in that matter I will go with my own. Word's won't sway me in this matter, simulations and a proven safety record would (it doesn't do so hot on the latter, okay no explosion occurred in Monju ... but only because they got really lucky).

Leaks happen and water is everywhere.

Re:Waste storage? (1)

dunkelfalke (91624) | more than 6 years ago | (#23133666)

what about molten salt or candu reactors? afair they can both go on spent lwr fuel.

Re:Waste storage? (0)

Anonymous Coward | more than 6 years ago | (#23134818)

Fuel recycling isn't that simple. For one thing, it doesn't pay. That is, the additional energy you recover with it does not pay for the expense of doing it. It's cheaper to store the waste as-is from a once-through system (which is what is being done now in the U.S.) than it is to reprocess it. Because they aren't economic, the benefits of reprocessing are mainly in potential savings for the long-term storage and the risks of long-term impacts if something goes wrong with it. On the other hand, you must contrast this benefit to shorter-term potential accidents at the reprocessing site and the availability of extracted plutonium (which could be diverted to make bombs). I doubt that pays off either in terms of the risks. It is possible to mitigate the bomb diversion risk by always keeping the material isotopically and/or chemically "poisoned" so that it wouldn't be good for bomb manufacture (e.g., plenty of Pu-240). This is only possible for some reprocessing techniques.

Good luck trying to find a site for the reprocessing plant. It would probably be more difficult than finding a site for long-term storage.

It's fine to say reprocessing is the answer, but it isn't an easy, cheap, or entirely safe option, and anyone who thinks diversion for bombs isn't an issue need only look at India's nuclear bombs. That's exactly how the plutonium for them was obtained.

Re:Waste storage? (0)

Anonymous Coward | more than 6 years ago | (#23133038)

2029 Asteroid is going to kill us all anyway so why are you so concerned about 100 years from now?

Re:Waste storage? (1)

Jeff DeMaagd (2015) | more than 6 years ago | (#23133126)

I thought some of the recycling ends up meaning that they have a large quantity of material with a low level of radiation. IIRC, France recycles their material, but Scandinavian countries complain because they're upstream from where France dumps their slightly "hot" water from their nuclear recycling facility.

Re:Waste storage? (1)

bluephone (200451) | more than 6 years ago | (#23133330)

Solution: Put the politicians in Yucca mountain with the waste.

Proven? (1)

EmbeddedJanitor (597831) | more than 6 years ago | (#23138450)

With the long history of testing we know exactly how these materials will perform 1000 years from now.

You suggest that recycling the fissionable material will eliminate, or greatly reduce, waste. Not so. The problem is that the fissionable material is only a very small percentage of the waste stream. Almost verything that has been through a plant is treated as waste. The bulk of this is low level waste with no recycling potential.

Other uses? (2, Interesting)

Rocketman_Ryan (1276180) | more than 6 years ago | (#23132706)

I'm wondering if this might have implications beyond use in nuclear reactors. One of the big concerns with a manned trip to Mars is long-term exposure to radiation while en-route. This means that any spacecraft you use will have to be shielded, or at least have a shielded compartment for use during periods of high solar activity.

Ceramics make good radiation shields, and could be great for low(er)-weight shielding for spacecraft, especially if you can use a method like this to extend the lifetime of the shielding to put it in line with the lifetime of the craft. The potential problem I can see is that ceramics are generally brittle, so you would probably need some sort of exterior shell to provide both structural rigidity and impact resistance. But considering all current spacecraft are metal-skinned anyway, this shouldn't be a huge issue.

Plus, if you're using a nuclear rocket for your ship, these things can pull double-duty! It's like a spaceflight magic bullet.

Gas Cooled Fast reactor (3, Interesting)

BlueParrot (965239) | more than 6 years ago | (#23133436)

Out of the generation IV proposals it is probably the gas cooled fast reactor that will benefit the most from this.
http://en.wikipedia.org/wiki/Gas_cooled_fast_reactor [wikipedia.org]

One of the major issues with global warming is that the hydrogen used to produce amonia and subsequently artificial fertilizer, is currently derived from natural gas. The process emits a lot of CO2 , and it isn't really feasible to
stop producing hydrogen as it could result in a collapse of agriculture due to drastically increased fertilizer prices.

Two generation IV reactors, the very high temperature reactor, and the gas cooled fast reactor, are aimed to resolve this by dramatically improving the efficiency of electrolysis of water. This can be achieved through so called thermochemical hydrogen production ( http://en.wikipedia.org/wiki/Sulfur-iodine_cycle [wikipedia.org] ), but it requires temperatures exceeding 800 C.

While it is likely that thermal reactors with helium coolant ( such as the pebble bed reactor ) could achieve this, it gets more tricky for fast reactors. Fast reactors have about 100 times less waste, better uranium utilization and the waste decays to safe levels between 100 and 1000 times quicker than for thermal reactors. The main catch is that the MUCH higher power density and neutron flux makes it difficult to find suitable materials. Sodium coolant doesn't work for hydrogen production since it boils before reaching the necessary temperatures, lead has corrosion issues especially at high temperatures and its high mass density makes it difficult to find materials that are strong enough at the temperatures required. Helium works, but because it has a much lower heat capacity than molten metals the reactor would likely reach higher temperatures under accident scenarios, and thus materials that can withstand a very strong neutron flux at high temperatures is absolutely necessary for a gas cooled fast reactor to be feasible.

Re:Gas Cooled Fast reactor (2, Funny)

polar red (215081) | more than 6 years ago | (#23133592)

All fine, but if you look at the actual cost of those too-complicated-to-be-ever-economical-systems, i have to wonder if they ever get marketed ... it will just be cheaper to go the wind/solar/electrolysis way, and certainly if they stop subsidizing nuclear so much.

Re:Gas Cooled Fast reactor (0, Flamebait)

BlueParrot (965239) | more than 6 years ago | (#23133676)

a) They are likely to be cheaper than existing reactors due to a simpler plant layout.
b) Nuclear is profitable many places where it isn't subsidized, in Sweden it is even taxed and still runs at a profit.
c) Solar/Wind are subsidized more than nuclear ( in terms of money per kwh ) in virtually every country that use them to any large extent.

To put it in terms of another poster, if Solar / Wind is so cheaper than nuclear (which is itself competitive with coal ), why isn't your house exclusively powered by them? Why do you wait for the government to do it for you when you could just go out and buy solar cells yourself? Given that both wind turbines and solar cells are heavily subsidized in many countries, and since they are allegedly cheaper than using other energy sources, one would think that it would be the deal of a lifetime , yet at best people use them to supplement their energy supply, and close to nobody actually use them exclusively. Care to tell me why ?

Re:Gas Cooled Fast reactor (1, Informative)

polar red (215081) | more than 6 years ago | (#23133710)

Solar/Wind are subsidized more than nuclear
you are DEAD WRONG. look up who Insures nuclear power plants. look up the research costs, look up who pays for the instances who check the plants ... THAT is all also part of subsidy.

Re:Gas Cooled Fast reactor (1)

polar red (215081) | more than 6 years ago | (#23133714)

why isn't your house exclusively powered by them?
next year, I will have cells on my roof.

Re:Gas Cooled Fast reactor (1)

BlueParrot (965239) | more than 6 years ago | (#23133778)

Right, so France and Japan spending billions to research sodium cooled reactor technology is the reason water cooled reactors are profitable in Sweden ( despite being taxed ) while Solar is not? The money spent on research during the last 2 decades is to be considered a subsidy to the plants that were built 40 years ago ? Give me a break. As for the instances that inspect power plants do you seriously think these costs get anywhere close to that of the power plants? Heck, ok, I'll bite and let you add a 10% cost to nuclear based on inspections ( and that really is a massive estimate ). Wind power is still massively more subsidized receiving close to half its revenue from government sources in some jurisdictions.

As for insurance, how many accidents have there been in the western world that resulted in a payout from this insurance? Care to estimate ( in percent ) how much this is compared to the overall budget of nuclear power generation?

What you have done is to parrot a bunch of lose claims that nobody has ever been able to back up as significant. The perhaps most silly claim is the so often repeated that renewables would be competitive if more money was spent researching them. Perhaps by the same token we should put equal amount of money into perpetum mobile machines, expecting them to start being successful if they just got the same amount of funding as those over subsidized renewables ?

Re:Gas Cooled Fast reactor (1)

polar red (215081) | more than 6 years ago | (#23133792)

Re:Gas Cooled Fast reactor (1)

BlueParrot (965239) | more than 6 years ago | (#23133922)

Uhm, by those statistics Nuclear gets about 4 times the money of renewables despite contributing many many times more energy. I.e, when you consider subsidies per unit of energy generated, nuclear receives far less than renewables. What next, are we to pay the same amount for one wind turbine as for one nuclear power plant and then call the nuclear plant subsidized because you didn't spend any money on solar ?

Re:Gas Cooled Fast reactor (1)

polar red (215081) | more than 6 years ago | (#23133958)

No, I say we drop _ALL_ subsidies. The problem with that of course, is that you can't get insurance for nuclear power plants.

Re:Gas Cooled Fast reactor (0, Flamebait)

polar red (215081) | more than 6 years ago | (#23133802)

As for insurance, how many accidents have there been in the western world that resulted in a payout from this insurance?
and what will happen when a serious nuclear meltdown occurs? who will pay for the damages and lives lost? I can bet it won't be the companies (see: chernobyl), but the government. Note : a serious meltdown WILL occur, cuts will always be made by managements, and NOTHING has ever been build that is 100% safe, 99,999% is NOT 100%.

Re:Gas Cooled Fast reactor (1)

BlueParrot (965239) | more than 6 years ago | (#23133896)

By that standard we shouldn't build windmills or factories producing solar cells either. While one single windmill may not be much of an issue, you need thousands of them to replace a single nuclear power plant ( and a single nuclear plant can replace ALL solar cells currently operating in the world ). Now while it won't get as much media attention, people die working with windmills. Some fall down servicing them, people die during steel mining etc... Saying a major accident WILL occur, is about as useful to the argument as me saying sooner or latter all windmills WILL catch fire simultaneously as the weather is windy after a long drought. The resulting fires could kill BILLIONS. It could happen, but it is so unlikely that you would rightly call me crazy if I considered it a reason not to build wind farms.

Btw, even a meltdown wouldn't necessarily hurt a single person in a modern nuclear power plant. A meltdown simply means the metal fuel in the core melts due to overheating. It doesn't necessarily mean the pressure vessel leaks, it certainly doesn't imply an explosion, and they have occurred without significant environmental consequences in the past ( Three Mile Island ). While the Chernobyl plant did not have any means of dealing with such a situation, modern western reactors are all built inside airtight concrete structures capable of withstanding a direct hit from a large airliner. A meltdown would be costly in the sense that you would ruin your expensive and fancy power plant, but it is unlikely it would have any major off-site consequences.

Re:Gas Cooled Fast reactor (1)

dunkelfalke (91624) | more than 6 years ago | (#23133686)

what about lead coolant? afair there were some russian submarines with lead cooled reactors.

Re:Gas Cooled Fast reactor (1)

BlueParrot (965239) | more than 6 years ago | (#23133728)

It could work, the problem is that if you want to use it for thermo-chemical hydrogen production you need to push temperatures above 800C. At those temperatures the protective oxide layers that prevent the steel from corroding dissolve into the lead coolant. Furthermore the steel itself starts losing its strength, which is a major issue if you use a heavy metal like lead. There is research into using ceramics and special metal alloys with silicon dispersed into its crystal lattice, but this is experimental at best.

Looks like Roland just heard of ... (1)

dbIII (701233) | more than 6 years ago | (#23139234)

... materials that are stopped from transforming into another because there in no room to move but will expand to fill small gaps where they exist. Interesting stuff but not a worldshaking new discovery since there are a few things like this.

The most common ceramic of this type to be used for the past few decades is known as "partially stablised zirconia". Engineering students generally find out about it in the first year of their course if they have been educated in the last twenty years. It's cool and interesting stuff with some applications like the above but sometimes other stuff is more useful - metal tubes can flex more than even a tough ceramic like PSZ, low conductivity can be a drawback etc etc.

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  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>
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