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GE To Turn World's Biggest Civilian Plutonium Stockpile Into Electricity
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."
This 'fission' technology sounds interesting, but is it safe?
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.
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.
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 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.
What if Iaran gets the bomb, we'd be better using all out plutonium to bomb them into oblivion.
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=
Is there a kind of plutonium that isn't radioactive?
There is no right to feel safe thru security vaudeville at the expense of everyone's freedom, privacy and tax money.
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.
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.
Don't forget about CANDU reactors. 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.
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.
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.
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)
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.
if this is supposed to be a new economy, how come they still want my old fashioned money?
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.
I'm pretty sure that's how Godzilla was created...
I am TheRaven on Soylent News
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 -
/TSG/
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.
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.
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
Excellent protein source, there.
Does anyone have a rough idea of how much electricity could be produced by this type of reactor using the 87 tons plutonium stockpile? Please express in terms of % of annual electricity consumption by Britain, or another unit readable by laymen.
I would have guessed that radiation was needed for that , too.
...the future crusty old bastards are already drinking the Kool-Aid.
Basically, not only will it be burning WASTE fuel, but, it is actually cheaper to burn this then to try and handle the 'waste' fuel. Look at WIPP. It is a true cluster. OTH, these can actually be built for a fraction of what it costs to store all that waste but instead makes money.
In addition, because it is modular, these can be added at the sites that are already handling nuke reactors. With this approach, it allows a plant that is already built to handle large power but heading towards closure to switch to this. That allows the grid, cooling, perhaps the generators, etc to continue being used.
But what else is missing is that the heat from this is so high. This is useful in areas like processing Lithium for batteries. The high cost of this is actually about the high temps that it takes to process them. With a reactor like this, the temperature can be used directly to do the work, rather than converting to electricity and back to heat. Basically, one reactor like this could process all the lithium that a nation would need (and more) while still using the waste heat for power (though to be fair, it will be a lot less; still not a waste ).
I prefer the "u" in honour as it seems to be missing these days.
This is simply an IFR. But the amazing thing is that this is going into America already.
I prefer the "u" in honour as it seems to be missing these days.
Here's a clue - liquid sodium is used for technical and not safety reasons.
Whoever is selling you on some snake-oil "sodium is safe" marketing line is not being honest to you and you are making yourself look naive and poorly informed by repeating it.
Two things, first it only consumes a small portion of nuclear waste and produces a larger volume of a different type of waste - which I'm sure you already know. Second, the established civilian nuclear energy producers have been the ones fighting the solutions to the nuclear waste problem on the basis of cost. I atteneded a seminar on Synrock over twenty years ago and it's only recently that it has been adopted anywhere due to governments pressuring reactor operators to do something with their waste.
I worked in the Navy in a military high pressure water reactor. The concept from the beginning was 'flawed' and not very efficient. The reactor they are proposing is 'better', but still not good. The problem with the efficiency of modern reactors is that they use a SOLID fuel. A very large byproduct of fission is Xenon. This Xenon is a HUGE neutron absorber (bad for continued fission) AND it causes fractures and destabilizes the fuel rods. That's why there is so much unburnt uranium and other fissionable materials left after a fuel rod is no longer viable. A massively more efficient design is a LFTR reactor. This isn't conjecture and it's not a theory, the gov't had a couple different ones that ran, one for several years, although it was never used to actually generate power. The design allows for a LIQUID fuel, where the impurities can be removed as it's running, and allows for an almost total burn of the fissionable materials. You could even introduce the 'waste' materials from a light water reactor and burn them up as well. There is a push amongst some very bright and motivated people to try and get more acceptance for a liquid flourine thorium reactor and in my opinion is the only way to go to generate nuclear power going forward. Do a search for LFTR and read up, it's as obvious as turning on a light in a dark room, but the entrenched politicians and corporate entities that have so much money invested in light water reactors won't give it the time of day.
No I wasn't looking for that term.
All of our current coal/gas/nuclear power plants are heat engines hooked up to an Rankine cycle steam plant. The maximum theoretical efficiency of any Rankine cycle is a function of the maximum temperature of the working fluid.
Thee is work going on to move to a Brayton cycle power plant. That one change can conceivably double plant efficiencies. But a Brayton cycle needs much higher temperatures than a Rankine cycle.
Look up Rankine and Brayton cycles on wiki.
I think one really important point, which distinguishes between nuclear "efficiency" and efficiency of solar/wind, is that when nuclear plants inefficiently consume nuclear fuel, all the unused energy is still there for capture and use later with almost no penalty.
One could argue the same is true for solar and wind, in that the sun keeps shining, the wind keeps blowing, so it doesn't really matter that it's not efficient.
So, in the end, what it comes down to is cost/kWh. That's really the only metric that's meaningful. The problem is, that especially for solar, and somewhat for wind, the very low efficiency translates to a high cost/kWh generated.
This is somewhat true for nuclear as well - right now it's more expensive than it could or should be. But nuclear gets by, because the amount of energy in each tonne of fuel is so enormous, and steam turbines are efficient "enough", that the economics for "expensive" nuclear are still competitive with other energy sources.
Nuclear also has a lot of potential to come down in price. Most of the cost of nuclear power, from what I've found in trying to research the subject, comes not from fuel, but from the actual generation infrastructure (which is not so different from the situation with solar and wind power).
But, the difference between nuclear and solar/wind with regards to financial competitiveness, is that a large part of the cost of nuclear power is very high regulatory costs, very low economies of scale (few nuclear plants are built per year, and in the U.S., we're only now starting to build new plants after a 30 year period in which no new plants were started), and high loan/financing costs.
Solar and Wind are starting to have economies of scale kick in, and the prices have been dropping to a point where, I won't say the price can't drop more, but we probably can't expect a lot of additional price decreases.
Nuclear is so "overpriced" right now, there is a lot of room for the cost of building nuclear plants to come down - *without sacrificing safety*.
Additionally, newer designs being developed right now should be cheaper to build because they are designed to be simpler, standardized, and in some cases, manufactured in factories (search for "Small Modular Reactor").
The GE-H S-PRISM discussed in this article is one such small modular reactor concept. The idea is that if they can build smaller nuclear plants, then utilities can buy "less" at a time, thereby saving money on loan/financing costs, and not taking the risk of buying such a big plant that they can't sell all the power they produce. Additionally, the smaller, factory made reactors should be able to be produced a bit cheaper using the normal tools and techniques of the industrial revolution which made many other manufactured good substantially cheaper than comparable goods which are 'hand-made'.
Just wanted to add a hopefully useful note: at least in theory, we don't have to store the "95%" (although in practice, that might be what current plans call for, as it might be simpler/cheaper to do that).
Reactor Grade Enriched Uranium fuel is about 95% U-238, and 5% U-235. U-238 is non-radioactive. After running the fuel through a reactor, most of the 5% of U-235 will be fissioned, and if I understand correctly, most of those fission products are highly radioactive (but only for about 300 years). During its time in the reactor, some of the U-238 will capture neutrons and be converted into isotopes of Plutonium. The Plutonium is radioactive, and if not burned in a fast reactor, will need to be disposed of as "waste". It seems like the figure I've heard for how much plutonium is generated in a light water reactor is somewhere around 3% of the original fuel? Not sure, but it was pretty low.
So, in theory, somewhere around 90 percent or so of the "waste" is non-radioactive U-238, which could at least potentially be separated from the rest of the waste, and separately disposed of as non-radioactive tailings (could be, for example, maybe buried back in the mines it was extracted from).
So, if only 5% of the fuel is actually fuel, how is it that this PRISM reactor can extract 100% energy, theoretically speaking? Above I mentioned that a low percentage of U-238 captures neutrons and becomes plutonium, which is both radioactive and fissile.
In a Fast Reactor (such as the PRISM), eventually you can convert almost all of the U-238 to plutonium (a little bit at a time, so you never have a large inventory of Pu at once), then fission the plutonium.
nuclear engineer here: nonsense, 85% of the energy of fission is released as heat energy. you are going to convert heat to electricity, without a heat engine?
should point out that 85% is by very nature of the "kinetic energy" of fission fragments you are talking about, they only travel a microscopic distance in a fuel pellet before being turned into heat. Most of the remaining 15% is gamma ray energy. you could convert all of that into electricity by unknown process, and still be mostly limited by heat engine efficiency for the 85%.