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GE To Turn World's Biggest Civilian Plutonium Stockpile Into Electricity

samzenpus posted more than 2 years ago | from the use-it-or-lose-it dept.

Power 241

First time accepted submitter ambermichelle writes "GE Hitachi Nuclear Energy has proposed to the U.K. government to build an advanced nuclear reactor that would consume the country's stockpile of radioactive plutonium. The technology called PRISM, or Power Reactor Innovative Small Module, would use the plutonium to generate low-carbon electricity. The U.K. has the world's largest civilian stockpile of plutonium. The size of the stockpile is 87 tons and growing. Nuclear reactors unlock energy by splitting atoms of the material stored in fuel rods. This process is called fission. For fission to be effective, neutrons – the nuclear particles that do the splitting and keep the reaction going – must maintain the right speed. Conventional reactors use water to cool and slow down neutrons, keeping fission effective. But water-cooled reactors leave some 95 percent of the fuel's potential energy untapped."

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New power source? (1)

Anonymous Coward | more than 2 years ago | (#38295062)

This 'fission' technology sounds interesting, but is it safe?

Re:New power source? (5, Insightful)

ae1294 (1547521) | more than 2 years ago | (#38295154)

This 'fission' technology sounds interesting, but is it safe?

Yes perfectly safe as long as nothing goes wrong.

Re:New power source? (4, Interesting)

JSBiff (87824) | more than 2 years ago | (#38295720)

You should really read up on the "Integral Fast Reactor" - the S-PRISM this article is about is evolved from the technology developed in the IFR project.

The main potential safety weakness of an IFR is the possibility of sodium leaks leading to a sodium fire (I'm not sure how they manage this risk; it certainly seems like a potentially nasty problem, but I'm sure they've taken some sort of measures to try to prevent that from happening; I hope they are effective).

But, Sodium fires aside, the type of problems you had an Chernobyl, TMI, and Fukushima-Daiichi simply cannot happen in an IFR-style reactor. You can't get supercriticality/runaway fiisson like happened at Chernobyl; you can't get a meltdown; you don't have to worry about steam pressure overwhelming the containment (because water is not used as the coolant, so hence no steam), and you can't get a hydrogen explosion (again, no water in the reactor).

You might get a hydrogen explosion if, somehow, water started mixing with the sodium, as sodium and water will combine to form sodium hydroxide and hydrogen gas, but if they can keep water out of the reactor, then no hydrogen explosions.

So far as I know, there have only been a few sodium fires amongst all the world's sodium cooled reactors over the last 60 years - the most famous one was in Japan back in the late 90's or early 00's, and while that scared the public, it wasn't actually a disaster - just a relatively minor industrial accident in the end. I've never heard of a sodium fire at a nuclear plant becoming a major problem, so I don't think the risk of sodium fires is actually a big, unmanageable 'ticking time bomb', but again, I'm no expert.

Still, I think the technology looks *very* interesting. Let's face it, we have a nuclear waste problem, and either IFR or another type of fast reactor (such as a molten salt fast reactor) are basically the only way to solve that problem. Let's stop fighting the solution to the nuclear waste problem. It truly is the only realistic solution - burn off that 100,000 year "plutonium problem".

Re:New power source? (3, Funny)

chris.alex.thomas (1718644) | more than 2 years ago | (#38296102)

just have a water sprinkler system to put out the fire! no more problems!

Re:New power source? (4, Informative)

Rising Ape (1620461) | more than 2 years ago | (#38296314)

You can't get supercriticality/runaway fiisson like happened at Chernobyl

Fast reactors are somewhat notorious for being trickier to control than (well-designed) thermal ones. It's very difficult to avoid a positive void coefficient, and fairly small changes in the fuel geometry can lead to large changes in reactivity. There was a meltdown in an early FBR caused by thermal expansion causing the fuel to bow inwards, increasing the reactivity. Phenix in France also had unexplained loss of reactivity incidents.

Re:New power source? (0, Interesting)

Anonymous Coward | more than 2 years ago | (#38296486)

Care to comment on Thorium MSR's?

Or are Gen IV reactors not producing weapons grade fissile material still forbidden from being discussed publicly amongst the Nuc. Eng. community, or suggested as an implemented design?

Re:New power source? (3, Interesting)

AmiMoJo (196126) | more than 2 years ago | (#38296882)

I was wondering why GE was trying to get a new reactor design built in the UK instead of its home country, the US. Then I realised why: our government is the only one that will pay for it. The Conservatives view the government as a way to fund commercial enterprises, to build stuff that no bank would back but which with most of the cost paid for out of taxation are a potential gold mine for the owner. That is the way we build nuclear plants here, the tax payer funds it and takes on most of the risk and clean-up cost while the commercial owner creams off a nice profit during the operational lifetime.

Unfortunately the government always gets ripped off when building anything and the companies running our nuclear facilities seem to be incompetent and unwilling to invest in safety. The plant TFA mentions, Sellafield, is notoriously accident prone, so I'm not sure it is a good idea to give them any more ways to screw up.

Thanks but no thanks GE, get back to us when you have built a working one paid for out of your own pocket.

Re:New power source? (1)

Tomato42 (2416694) | more than 2 years ago | (#38295876)

At least it doesn't go wrong every second it is generating energy, unlike fossil fuels... Or doesn't go wrong big time often, unlike hydro... And actually works round the clock, unlike "renewables".

Re:New power source? (1)

fish_in_the_c (577259) | more than 2 years ago | (#38296042)

hmm... haven't studied this. Is there a nonzero chance of large area's being rendered uninhabitable for 100 + years when one of these things explodes because it was hit by ( bus, tsunami, terrorist)?

If so i still oppose their use on the grounds that the low frequency risk is still beyond catastrophic. Otherwise sounds interesting.

Suppose we only have 1 Chernobyl like event every 100 years. in 1000 years there 10 areas the size of some U.S states that would be toxic to human life for a longer period of time then most governments have exists. Seems quite the legacy to leave the future to me.

Re:New power source? (3, Informative)

Anonymous Coward | more than 2 years ago | (#38296262)

All power sources are problematic. Energy has a way of making environments uninhabitable to humans... When you start storing large amounts of energy in small spaces things get more dangerous.

But don't let that fool you. Coal seam fires for instance: http://en.wikipedia.org/wiki/Centralia,_Pennsylvania can make an area uninhabitable for decades, centuries...
Hydro destroys ecosystems down stream; to some humans, this can destroy their livelihood. And when one damn fails it'll kill hundreds to thousands in a few minutes...

Nuclear is just scary because its a black box that "normal people" don't understand. When a dam fails, those thousand people die quickly in an easy to comprehend way. When a criticality event happens and people drop to a gamma burst, well, lets just say a wall of water is a lot less scary than nothing at all... And, in the end, all energy storage mediums have risks: to the environment, to people, and to economies...

Re:New power source? (3, Insightful)

geekoid (135745) | more than 2 years ago | (#38296268)

" low frequency risk is still beyond catastrophic.

Not with modern generators.
http://en.wikipedia.org/wiki/Integral_Fast_Reactor [wikipedia.org]
Liquid metal thorium reactor are incredibly safe.
No event in any nuclear reactor that has ever happened can happen in one. Plus you can burn waste in them.
Oh and the waster from these return to background radiation levels in 200-500 year. Very workable, and possible to store on site. No shipping the waste.

The US government should be building 20 of these right now. And the US government should operate them;remove the desire to make bonuses , and all other problems go away with it.

These are the solution until we can get cheaper solar, or maintainable fusion.

Re:New power source? (4, Interesting)

Tomato42 (2416694) | more than 2 years ago | (#38296286)

Area under water behind a dam is uninhabitable and unarable, same goes with solar. Wind is just uninhabitable. If you count the amount of land required by them and compare to land made "uninhabitable" by nuclear, average over power generated, nuclear is a clear winner.

The radiation levels in Chernobyl Zone are lower than natural background radiation in some areas around the globe. Year of living in Ramsar in Iran exceeds nuclear industry limits during emergencies! Calling them "uninhabitable" for 1000 years is a bit of an overstatement... Unarable for food production, maybe, but then you can use those areas for production of automotive fuel.

Oh, and don't forget the amount of land made unarable and uninhabitable by heavy metal poisoning from regular industry, just look at mercury pollution in USA.

Re:New power source? (1)

Surt (22457) | more than 2 years ago | (#38296852)

The dam one is rather unfair. If you look at a slightly wider area, the land behind a dam usually rises in overall value (because people like lake-view properties with access to cheap power).

Re:New power source? (1)

haruchai (17472) | more than 2 years ago | (#38296226)

It's renewables, not "renewables". You're making an implication that what is commonly called renewable energy is not - that's flat-out wrong. Their primary weaknesses are that they are intermittent and relatively diffuse. Neither of those has anything to do with the fact that they are "renewable". Understood?

Re:New power source? (1)

Tomato42 (2416694) | more than 2 years ago | (#38296362)

Sun and geothermal aren't bottomless sources of energy, they are huge but not infinite. Why can't we call them sustainable? Oh, right, forgot that includes nuclear too. Move along.

Re:New power source? (2)

Endo13 (1000782) | more than 2 years ago | (#38296806)

No, you're flat-out wrong. The term 'renewable' indicates an energy source that either never runs out or can be indefinitely replaced. There currently exists no such energy on earth. Solar is no more renewable than any fossile fuel; our great big ball of fire out there is slowly burning out, and when it's done there is absolutely nothing we can do to replace it. We also can't keep renewing it so it doesn't burn out. In fact, if anything fossile fuels are more renewable than solar because it is possible to replenish (ie. renew) them. It just takes a lot of time, and we use them far faster than they can be replenished.

Re:New power source? (3, Funny)

Dunbal (464142) | more than 2 years ago | (#38295166)

Living entails a 100% chance of dying - is living safe?

Re:New power source? (0)

Anonymous Coward | more than 2 years ago | (#38295392)

No. Living is NOT safe. Nobody asked me if I wanted to be conceived. So now I must face the fact that I will die. I can from nothingness, and now I must contemplate returning to nothingness. Self-awareness sucks ass. Ignorance is bliss!

Re:New power source? (1)

fish_in_the_c (577259) | more than 2 years ago | (#38296104)

"I came from nothingness, and now I must contemplate returning to nothingness" -- can you prove that?
It would seem inconsistent with all the scientific evidence. Or do you know of some event which has no cause?

Re:New power source? (-1)

Anonymous Coward | more than 2 years ago | (#38296468)

Crackpot alert. Bible sites are THAT way ----------->

Re:New power source? (1)

StikyPad (445176) | more than 2 years ago | (#38296424)

Living doesn't entail a 100% chance of killing or maiming other people, nor does dying. I would say the chances in either event are actually much closer to zero. So yes, your being alive is reasonably safe for me and those around you.

Re:New power source? (1)

Jeng (926980) | more than 2 years ago | (#38295286)

This 'fission' technology sounds interesting, but is it safe?

Depends on what your definition of safe is.

Re:New power source? (1)

MobileTatsu-NJG (946591) | more than 2 years ago | (#38295378)

Depends on what your definition of safe is.

Okay, I'll rephrase his question: Will we be irradiated by a plant run by PHBs?

Re:New power source? (1)

Jeng (926980) | more than 2 years ago | (#38295462)

Okay, I'll rephrase his question: Will we be irradiated by a plant run by PHBs?

Luckily PHB's magnify incompetence and therefor it is unlikely that the plant will ever be operational, so in that regard we may be safe.

Re:New power source? (1)

Tomato42 (2416694) | more than 2 years ago | (#38295690)

We will be irradiated less by nuclear power plant run by PHBs than inhale smoke from fossil fired power plants or breathe water from hydro if they are run by the same people.

Nuclear is safest method (and certainly safest proven method) of energy production: http://www.externe.info/ [externe.info] (that's European Commision published research)

Re:New power source? (0)

Anonymous Coward | more than 2 years ago | (#38295782)

Depends on what your definition of living is.

Re:New power source? (0)

Anonymous Coward | more than 2 years ago | (#38295950)

What could possibly go wrong?

I was waiting... (1)

mattie_p (2512046) | more than 2 years ago | (#38295064)

for the wry remark the editors usually leave after posting the summary. I think the world definitely needs to explore SAFE nuclear power options, especially those that use existing supplies of fissile and radioactive material.

Re:I was waiting... (1)

leucadiadude (68989) | more than 2 years ago | (#38295666)

The PRISM is based on the IFR. One big f'n tank of liquid sodium. No thanks, I would rather see the plutonium used for LFTR start charges.

Re:I was waiting... (1)

tmosley (996283) | more than 2 years ago | (#38296508)

What's the problem? Is the sodium radioactive? Because if it isn't, it is no worse than using molten sodium to store solar power. Better even, because the facility isn't on the surface, but buried, and doesn't have to be exposed to the air (allowing for a lot more shielding). It seems to me that if the sodium comes out underground, you get some magma until the heat dissipates, and that is it. I don't see what the big deal is.

Can you please explain what's an atom again? (1)

zill (1690130) | more than 2 years ago | (#38295114)

Nuclear reactors unlock energy by splitting atoms of the material stored in fuel rods. This process is called fission.

This is /. I'm pretty sure everyone here knows about fission.

Re:Can you please explain what's an atom again? (1)

Victor_0x53h (1164907) | more than 2 years ago | (#38295150)

Furthermore why is water cooling so inefficient; does GE's PRISM fix this problem?

Re:Can you please explain what's an atom again? (1)

drewsup (990717) | more than 2 years ago | (#38295310)

*sigh.. from TFA

PRISM is a so-called “fast reactor.” It uses liquid sodium, rather than water, to cool the reactor. The sodium allows the neutrons to maintain higher energies and to cause fission in elements such as plutonium more efficiently than water-cooled reactors.

Re:Can you please explain what's an atom again? (1)

JTsyo (1338447) | more than 2 years ago | (#38295614)

What percent is left compared to water? RTA and let us know.

Re:Can you please explain what's an atom again? (0)

Anonymous Coward | more than 2 years ago | (#38295438)

Liquid sodium is mock more efficient. And if it leaks, you can just mop it up with water!

GE - someone set us up the bomb!

Re:Can you please explain what's an atom again? (0)

Anonymous Coward | more than 2 years ago | (#38296034)

it's up us not us up.

someone set up us the bomb.
get your memes right.

Re:Can you please explain what's an atom again? (0)

jo_ham (604554) | more than 2 years ago | (#38295678)

Who says it uses water for cooling? Oh yes, the fucking article. ;)

Re:Can you please explain what's an atom again? (0)

Anonymous Coward | more than 2 years ago | (#38295208)

As someone who barely passed High School and has had absolutely no higher education I just have to say.

If you don't know what something is LOOK IT THE FUCK UP.

Thank you.

Those "Submitter is an idiot cause I don't know what a kumquat is." posts are starting to piss me off.

Re:Can you please explain what's an atom again? (0)

Anonymous Coward | more than 2 years ago | (#38295362)

What's a kumquat?

Re:Can you please explain what's an atom again? (0)

Anonymous Coward | more than 2 years ago | (#38295404)

Kinda like an orange, except the size of an olive.

Re:Can you please explain what's an atom again? (3, Informative)

NEDHead (1651195) | more than 2 years ago | (#38295482)

kumquat:unit of kum

Re:Can you please explain what's an atom again? (0)

jo_ham (604554) | more than 2 years ago | (#38295662)

Oh I don't know, given the larger-than-expected percentage of climate change deniers and misinformed scaremongers on every nuclear related story. I wouldn't expect it for such an "educated" audience (you need a minimum level of literacy and tech literacy to really understand a lot of the topics on here).

I mean, look at the story about the molten sodium sphere modelling the earth's core - a whole bunch of non-ironic comments proclaiming how flawed it all was and how they'd clearly not accounted for x, y or z really obvious thing.

I think we might have to go back to the Bhor model of the atom at this rate.

Re:Can you please explain what's an atom again? (0)

Anonymous Coward | more than 2 years ago | (#38296266)

Speaking as a man-made climate change skeptic (but, eh, your brush is probably broad enough that you will label me as an evil denier), I am all for nuclear power.

Re:Can you please explain what's an atom again? (1)

tmosley (996283) | more than 2 years ago | (#38296540)

I never saw such an argument pop up, and I'm one of those evil "deniers" who poison wells and eat liberal babies.

Water-cooled reactors are only 5% efficient? (3, Insightful)

timeOday (582209) | more than 2 years ago | (#38295126)

I am amazed that conventional water-cooled reactors are only 5% efficient. It sure casts the seemingly low efficiency factors of other alternative fuels(such as the cheapest solar panels) into a different light.

Re:Water-cooled reactors are only 5% efficient? (2, Informative)

Anonymous Coward | more than 2 years ago | (#38295176)

Save solar, wind and various methods of deriving hydroelectric power, all electric power generators boil down to the downright caveman primitive method of heating water into steam to drive turbines. No one has yet figured out anything better.

Re:Water-cooled reactors are only 5% efficient? (1)

Anonymous Coward | more than 2 years ago | (#38295222)

... all [widely used] electric power generators boil down to the downright caveman primitive method of heating water into steam to drive turbines. No one has yet figured out anything better.

Steam move things good!

Re:Water-cooled reactors are only 5% efficient? (1)

HornWumpus (783565) | more than 2 years ago | (#38295714)

You forgot internal combustion, turbine and animal powered generators. No steam involved.

Re:Water-cooled reactors are only 5% efficient? (5, Informative)

Chrisq (894406) | more than 2 years ago | (#38295284)

I am amazed that conventional water-cooled reactors are only 5% efficient. It sure casts the seemingly low efficiency factors of other alternative fuels(such as the cheapest solar panels) into a different light.

But you are talking about 5% of the energy from a fuel with an energy density which is about 1,000,000 times the energy density of coal

Re:Water-cooled reactors are only 5% efficient? (1)

haruchai (17472) | more than 2 years ago | (#38296402)

Nevertheless, it's unbelievable that after 50 years of nuke plants, we've not moved on to more efficient plants or don't do reprocessing on a mass scale. It's rank stupidity to rip up the earth to extract a fairly rare substance for 5% of its potential and then have to find safe methods to store the 95% for 10,000 years.

Re:Water-cooled reactors are only 5% efficient? (0)

tmosley (996283) | more than 2 years ago | (#38296612)

That's what happens when you let the government regulate safety. They freeze technology where it was when they got involved, or shortly thereafter. Seems to always happen. That's why we still have human flight controllers who sleep on the job after 48 hour shifts (exaggeration, but only slight). That's why we don't have flying cars. That's why we don't have non-addictive, side effect-free pain killers.

Re:Water-cooled reactors are only 5% efficient? (2, Interesting)

Anonymous Coward | more than 2 years ago | (#38295328)

It's not the thermodynamical efficiency. The usual water cooled
reactors use slow neutrons (water slows the initially fast neutrons from
fission to slower speeds). These reactors can only extract a fraction of available
energy from the fuel. Liquid metal cooled reactors use heavy metal
atoms (sodium, eutectic lead/bismuth) as primary coolant which does not slow
neutrons. The fast neutrons are used in fast breeder reactors, which can burn
the fuel more thoroughly or create new fuel (U-239/Pu) as they run.

Re:Water-cooled reactors are only 5% efficient? (3, Informative)

Anonymous Coward | more than 2 years ago | (#38295440)

It's not 5% efficiency. Of the thermal energy they produce, in fact, more of it can be used than coal, since nuclear reactors can operate at higher temperatures than coal furnaces. However, if someone came up with a coal fuel cell, perhaps it could be even more efficient, since it wouldn't lose energy to thermalization. Muscles are not heat engines, they are like 95% efficient.

Only 5% of the nuclei that can be fissioned are. In a different reactor, more of the fuel could be fissioned; with current reactors, unburnt fuel is left piling up. Until, apparently, there's enough unburnt fuel to make that different reactor viable.

This is great news.

Re:Water-cooled reactors are only 5% efficient? (0)

Anonymous Coward | more than 2 years ago | (#38295600)

To clarify: conventional light-water reactors (LWRs) use around 5% of the available fissionable material in the fuel. U-235 is fissile, that is it undergoes fission when struck by a "slow" neutron. U-238 is fertile, that is it absorbs neutrons and radioactively decays to something fissile (Pu-239). All of these materials (and others in spent LWR fuel) are fissionable, that is they can undergo fission when bombarded with "fast" neutrons. The GE PRISM reactor is a fast reactor -- it's neutrons can induce fission in fissionable material. A fast reactor coupled with a reprocessing plant, like they're proposing can in principle consume all of the fissionable material.

The actual conversion process from fission to steam is governed by thermodynamics. Thermal efficiences of around 33% (more or less) are typical -- same as with coal. The energy density of these two fuels is vastly different, however -- especially when you're planning to use a fast reactor.

IAANE (I am a Nuclear Engineer), but not one working for GE. That said, It think it's a good idea in principle. I'll be interested to see the particulars. Especially if they're hiring...

Re:Water-cooled reactors are only 5% efficient? (1)

leucadiadude (68989) | more than 2 years ago | (#38295734)

PRISM is a commercialized version of the Integral Fast Reactor (IFR). I personally would rather that plutonium be used for LFTR start charges than used in a big tank of liquid sodium. But since we taxpayers have already spent $35 billion on the IFR and related tech since 1965, it would be nice to get some use out of all that money, even of it is GE that benefits. Just hope there are no major sodium leaks.

Re:Water-cooled reactors are only 5% efficient? (1)

Synerg1y (2169962) | more than 2 years ago | (#38296528)

This goes beyond money, nobody on slashdot has mentioned that we have an "energy problem" which involves the end of society as we know it once we run out of coal, aka the forecasted "dark age". We've got enough alternatives to coal that not a whole lot of people think that way anymore, but.. I think most would agree our "green" energy, while beneficial, is not maintainable for the energy needs of modern society. Thus, GE's research and potential benefit to the human race outweighs any profit they can incur form this.

Re:Water-cooled reactors are only 5% efficient? (2)

MozeeToby (1163751) | more than 2 years ago | (#38295624)

And the energy density of a chunk of Uranium is still orders of magnitude higher than any other practical fuel source. Also, it's not as if we couldn't refine and recycle the fuel and squeeze more of the energy out of it later. Today's nuclear waste storage is tomorrow's 'unlimited energy source'.

Re:Water-cooled reactors are only 5% efficient? (1)

Andy Dodd (701) | more than 2 years ago | (#38295722)

I don't know if "efficiency" is the right word... This implies that 95% of the energy available is wasted as heat which can never be used again.

That isn't the case with traditional light water reactors - they don't waste much more heat than any other heat-engine-based plant - however, 95% of the potential energy in their fuel simply can't be used in the first place!

I believe one of the statistics of the Integral Fast Reactor project was that the United States' existing spent fuel stockpiles would be able to provide 100% of the country's electric needs for at least a century.

The GEH PRISM proposal looks very similar to the IFR, except using a "small modular" plant design - smaller plants mean less risk and easier containment if one of them fails. (Fukushima taught us a "large plants are bad" lesson - Fukushima would have been MUCH more manageable with some physical separation between the troubled units.)

Of note in the diagrams - PRISM only provides its optimal efficiency claims with reprocessing - with reprocessing, they can extract nearly all of the potential energy in the fuel and the residual waste is only dangerous for 300 years. Without reprocessing, the waste is dangerous for 300k years and they maybe get another 5% of the energy.

Re:Water-cooled reactors are only 5% efficient? (4, Informative)

jo_ham (604554) | more than 2 years ago | (#38295758)

It's not that it's not that efficient, it's that it really doesn't need to be. The energy from fission is mostly captured (although you are dumping a lot of heat), but crucially it leaves high energy products behind in the fuel. It's what makes the spent fuel so hazardous to deal with, which is why it's crazy to suggest burying it in the ground!

Why bury something that has so much juicy energy still in it that we can extract with current technology? The answer is political, of course.

The other factor to consider is the sheer magnitude of the energy we're talking about here. E = mc^2 is not just a handy soundbite.

Re:Water-cooled reactors are only 5% efficient? (1)

AmiMoJo (196126) | more than 2 years ago | (#38296620)

Why bury something that has so much juicy energy still in it that we can extract with current technology? The answer is political, of course.

The UK used to lead the world with nuclear power. We had more of it than anyone in the 60s, but then we started trying to build new advanced designs which turned out to be harder than we thought. By the time they were coming online in the early 80s the Conservative government was busy selling off all energy infrastructure, but no-one would buy the nuclear bits because of the enormous costs and enormous liabilities.

So now when someone comes along with a fantastic new technology that will solve all our problems we are naturally sceptical. TFA is just a web page written by the people behind this scheme so you can't take a single word for granted. GE is a US company and Hitachi is a Japanese company, but for some reason their home markets don't seem to be interested in reusing the old fuel stockpiles. They could even make some extra cash by buying up ours.

Re:Water-cooled reactors are only 5% efficient? (1)

jo_ham (604554) | more than 2 years ago | (#38296780)

Who said anything about new technology? We have the technology we need right now to reprocess and use spent fuel from PWRs in breeders and other types of reactors, but it's politically sensitive to build reactors that can be purposed to make Pu for weapons if desired. No need for any new pie in the sky technology.

Re:Water-cooled reactors are only 5% efficient? (0)

Anonymous Coward | more than 2 years ago | (#38296068)

I am amazed that conventional water-cooled reactors are only 5% efficient. It sure casts the seemingly low efficiency factors of other alternative fuels(such as the cheapest solar panels) into a different light.

The thermal efficiency of a typical PWR is approximately 33%.

isn't untapped energy a more universal problem? (3, Insightful)

khallow (566160) | more than 2 years ago | (#38295128)

But water-cooled reactors leave some 95 percent of the fuel's potential energy untapped."

I gather the problem is that decay products poison the fuel after it's been run for a while. One would still need to reprocess fuel rods on a regular basis. But once that's done, you can get more than 5% of the energy from a fuel rod.

Re:isn't untapped energy a more universal problem? (1)

RandomChars (1455331) | more than 2 years ago | (#38295156)

yeah, but what about the energy cost of reprocessing?

Re:isn't untapped energy a more universal problem? (1)

Anonymous Coward | more than 2 years ago | (#38295214)

It's negligible. The UK has been reprocessing it's own and a whole bunch of other countries fuel for a long time out of a single site. If the process was net negative, that clearly wouldn't be feasible.

Re:isn't untapped energy a more universal problem? (1)

khallow (566160) | more than 2 years ago | (#38295228)

It'll be substantial, but my impression is less so than creating a new fuel rod in the first place.

Nuclear power efficiency (0)

Anonymous Coward | more than 2 years ago | (#38295200)

is pretty low as we are using fission as a heat source to heat (boil) water that transfers its heat to another water to drive turbines.
If you calculate the ratio of energy released to the energy produced (electricity) then this is VERY low.
This will probably stay low until we figure out how to convert gamma rays to electricity directly.

Re:Nuclear power efficiency (2)

Smidge204 (605297) | more than 2 years ago | (#38295288)

Today's nuclear plants are ~35% or so thermal efficiency, which is not that bad. Upgrading the generating end to a closed cycle turbine loop and staging multiple loops can raise that efficiency a great deal - 50%+ is realized in some newer natural gas power plants. The nuclear part itself is not the limiting factor.
=Smidge=

Re:Nuclear power efficiency (2)

leucadiadude (68989) | more than 2 years ago | (#38295808)

The higher the temperature of your working fluid, the higher your possible theoretical efficiency can be. The best out there are hitting 60% with a very high temp gas turbine with a steam generator hooked to it's exhaust and a rankine cycle attached to that.

There are some advanced reactor designs that can hit 50% if built, mostly due to higher working temperatures.

Re:Nuclear power efficiency (0)

Anonymous Coward | more than 2 years ago | (#38295952)

Or you can use the warm water to raise crocodiles.

Re:Nuclear power efficiency (1)

TheRaven64 (641858) | more than 2 years ago | (#38296098)

I'm pretty sure that's how Godzilla was created...

Re:Nuclear power efficiency (1)

tmosley (996283) | more than 2 years ago | (#38296652)

Excellent protein source, there.

Short sighted (1)

Chrisq (894406) | more than 2 years ago | (#38295234)

What if Iaran gets the bomb, we'd be better using all out plutonium to bomb them into oblivion.

Re:Short sighted (1)

LWATCDR (28044) | more than 2 years ago | (#38295282)

Uranium works fine.

Re:Short sighted (2)

Alwin Henseler (640539) | more than 2 years ago | (#38295416)

If Iran gets the bomb, I hope for all Iranians its government won't be stupid enough to use it (in any way, like running a test explosion somewhere).

And if any country would feel the urge to stop Iran from obtaining a nuclear bomb, let's hope for all our sakes conventional bombs would be used for that job.

In the meanwhile, "The PRISM reactor actually disposes of a great majority of the plutonium as opposed to simply reusing it over again without ever actually ridding the planet of the substance." sounds like a very good plan to me.

Re:Short sighted (2)

geekoid (135745) | more than 2 years ago | (#38296340)

Anything a nuke can do, conventional bombs can do. It's just takes more.

radioactive plutonium (2)

Anomalyst (742352) | more than 2 years ago | (#38295366)

Is there a kind of plutonium that isn't radioactive?

Re:radioactive plutonium (0)

Anonymous Coward | more than 2 years ago | (#38295410)

iPlutonium

Re:radioactive plutonium (2)

leucadiadude (68989) | more than 2 years ago | (#38295830)

Technically speaking, anything in the periodic table over Pb208 (Lead) is radioactive. It's just some of these elements have REALLY long half lives. And the longer the half life, the lower the radioactivity...

Re:radioactive plutonium (2)

Amouth (879122) | more than 2 years ago | (#38295908)

considering all atoms have some half life and there for are in some way radio active i'd have to say no.. but if you don't consider normal every day stuff radioactive then i'd point you at Plutonium 244

http://en.wikipedia.org/wiki/Plutonium-244 [wikipedia.org]

with a half-life of ~80 million years the radio activity from it would be very minimal

Re:radioactive plutonium (4, Informative)

iggymanz (596061) | more than 2 years ago | (#38295932)

no. but the usual Pu-239 isn't very radioactive, just emits alphas slowly with a very long half life of 24,200 years. That radiation can't even penetrate your skin or go through a piece of paper. Pu-240 is artificial, usually decays by alpha but sometimes spontaneously fissions, it too has long half-life of more than 6500 years. Then there is Pu-238, emits huge amounts of alphas with its short half-life of 88 years, it's used in RTG batteries and also radioisotope heater units. A kilogram of the stuff gives off 500 watts.

Re:radioactive plutonium (1)

StikyPad (445176) | more than 2 years ago | (#38296510)

500 watts per what?

Re:radioactive plutonium (0)

Anonymous Coward | more than 2 years ago | (#38296816)

Kilogram.

Re:radioactive plutonium (0)

Anonymous Coward | more than 2 years ago | (#38296830)

Per kilogram of the stuff. Oh, heat!

Re:radioactive plutonium (0)

Anonymous Coward | more than 2 years ago | (#38296864)

500 watts = 500 joules per second. The Watt is the unit of power (energy per second).

What would this efficiency be? (0)

Anonymous Coward | more than 2 years ago | (#38295402)

Shouldn't we wait till we have developed something that is over 100% efficient? You know like how they keep putting off solar and wind and such because it's not efficient enough? Or is this just a way of cleaning out the plutonium stockpiled. And where will the waste of this go? Think people think!

Re:What would this efficiency be? (1)

Tomato42 (2416694) | more than 2 years ago | (#38295816)

They are proposing to burn this waste in those reactors not only to reduce the amount of it, but also to generate power from it. (that is fission burn, not the pathetic chemical burning mind you)

Re:What would this efficiency be? (1)

iggymanz (596061) | more than 2 years ago | (#38296070)

Sorry, but in this universe we have to obey the laws of thermodynamics. There are no 100% efficient electric power generation systems. The efficiency of a real world wind turbine can't be more than 30%. A heat engine (including steam turbine systems or using solar to heat working fluid) can't be more efficient than carnot efficiency limit, less than 42% for real world plants. Direct solar conversion to electricity can't be more than 34% efficient.

CANDU (3, Interesting)

FeatherBoa (469218) | more than 2 years ago | (#38295568)

But water-cooled reactors leave some 95 percent of the fuel's potential energy untapped.

Light water reactors, sure. But heavy water reactors are a whole different kettle of fish. CANDU can already burn anything from natural uranium through plutonium. Hot stuff you just dilute down.

No need to invent some new crazy reactor, just burn it at Bruce or Pickering.

Re:CANDU (1)

Andy Dodd (701) | more than 2 years ago | (#38295790)

I think even CANDU has limitations of energy extraction that prevent it from extracting as much energy from the fuel as a breeder+reprocessing cycle like the IFR (and PRISM seems to be very similar to the IFR).

Re:CANDU (2)

tlhIngan (30335) | more than 2 years ago | (#38296368)

Yes, CANDU is actually very inefficient - it doesn't extract all the usable fuel as other reactors can.

However, it does have the advantage that it's impossible to have a meltdown - heavy water is a great moderator. In fact, it's required in order to have a reaction - if there's no heavy water, the fuel's inert. And normal water impedes the reaction as well, so if the cooling system leaks, the reaction stops as well.

Plus, the fuel that comes out needs even heavier processing to become weapons grade.

Re:CANDU (1)

AmiMoJo (196126) | more than 2 years ago | (#38296688)

Right, and TFA is just a page on the manufacturer's web site. I smell the foul aroma of bullshit. After all if it were as good as they make out why are they trying to sell one to the UK and not just building on in the US or Japan? The US doesn't even have a long term storage facility at the moment and spent fuel is building up at reactor sties, and once that lot is burned up they could charge the UK to deal with their waste.

wording (4, Insightful)

StuffMaster (412029) | more than 2 years ago | (#38295608)

I'm getting tired of all these posts saying "some entity to do something" when the summary says "proposed".

Assuming that "to" means "going to" to everybody else as it does me, I'd appreciate it if the editors could stop doing or allowing that.

CANDU? (1)

mmontour (2208) | more than 2 years ago | (#38295658)

Don't forget about CANDU reactors [ccnr.org] . They use a heavy-water moderator and are able to burn a wide variety of fuels including plutonium, natural uranium, or "spent" fuel from a light-water reactor.

Next on slashdot, three random unrelated facts. (1)

AaronLS (1804210) | more than 2 years ago | (#38295674)

It seems to imply that to take advantage of the excess stockpiles of fuel... we should use less of the fuel by using a more efficient process? Oh by the way let me throw a random definition in there so maybe you won't notice how little sense this article makes.

If you have more fuel and want to take advantage of it, the biggest hurdles are probably finding a method that's safe, over comes public opinion, and is cheap enough to allow you to build enough reactors/plants to consume that fuel.

Re:Next on slashdot, three random unrelated facts. (0)

Anonymous Coward | more than 2 years ago | (#38296242)

eventually when things get desperate enough the opinion will change.. opinion is not based on reality, just on a reaction to it.

has ANYbody had a stable LMFB? (1)

swschrad (312009) | more than 2 years ago | (#38295972)

the history of liquid sodium reactors has been a sad one, look up the Fermi #1 unit in Detroit some time. basically the job of keeping the liquid sodium, which is mightily explosive and gets mightily radioactive as a moderator, inside away from air and water is something that hasn't been solved yet. I would not be stumping the countryside trying to site one.

Geeky density fun (4, Interesting)

thatseattleguy (897282) | more than 2 years ago | (#38296110)

Just 'cuz I was curious, and it has some peripheral bearing on the question - assuming 19.816 gm/cm^3 for the density of Pu (more than lead) and also assuming (since it's the UK) we're talking "tons" = metric tonnes = 1000kg = 10^6 gm -

87 x 10^6 gm / 19.816 gm/cm^3 = 4.39 x 10^6 cm^3 = 4.39 m^3.

4.39 cubic meters is a single cube 1.637 meters on a side (or a little more than 5 feet/side, for us backward Yanks). More or less the size of a smallish SUV, yes?

Of course their Pu isn't, one hopes, stored all in one solid cube, which would probably exceed critical mass by some large factor. But still, it's not a massive physical quantity of material you're talking about here. /TSG/

Fallen this far? (1)

pz (113803) | more than 2 years ago | (#38296646)

Has Slashdot fallen so far that we need hand-holding on what fission is, and we accept FUD on reactor efficiency in the summary?

For shame, samzenpus.

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