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back to article New 'supercritical' generators to boost nuclear output by 50%

US government boffins say they – or perhaps their rivals – will soon roll out a new and much more efficient type of turbine generator which is expected to be a boon to so-called "thermal" powerplant technologies such as coal, gas, oil and nuclear. Most kinds of renewable generation – wind, tidal, hydro, solar-photovoltaic etc – …

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Damn government interference

Those DoE labs are always interfering...

A big bump in efficiency is just what's needed for coal plants: remove the last excuse for whining about the high cost of reducing pollution.

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Joke

Hmmm...

Sounds like we're gonna need more CO2.

Everyone should do their part. I'll leave my car idling overnight tonight.

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Coat

I went on ...

the London to Brayton cycle run once and that took a lot of energy :-)

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WTF?

Brayton, Selby ?

Like...

why ?

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hmmm

20MW from the back of a transit van wouldn't be bad.

Do they mean you'd have to keep the van parked next to a nuclear power station, though?

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so

how much is this like a magnox reactor then?

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"how much is this like a magnox reactor then"

No at all. This governs the working fluid in the turbine stage - which will be steam in any conventional nuclear plant

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Boffin

Great!

Now can we slap one of them on a LFTR (liquid fluoride thorium reactor)?

http://en.wikipedia.org/wiki/Molten_salt_reactor

http://www.youtube.com/watch?v=AHs2Ugxo7-8

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Boffin

@Oninoshiko

Yes.

Molten salts react *very* badly with that most common turbine fluid, water.

Note however it's not just the fluid its the specific *state* it's in that matters. C02 is more readily available than Helium, the other popular fluid for this task (and a *lot* cheaper).

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Welcome

Intriguing but very weird

For years generators have been pushing the system pressures *up* so the efficiency rises as the steam temp rises (pressurized water reactors hitting c300c and several 100 atm while the latest kit is IIRC pushing 500c).

Supercritical CO2 goes critical at about 31c and 73 Atm.

http://webbook.nist.gov/cgi/fluid.cgi?TLow=217&THigh=304&TInc=1&Applet=on&Digits=5&ID=C124389&Action=Load&Type=SatP&TUnit=K&PUnit=MPa&DUnit=mol%2Fl&HUnit=kJ%2Fmol&WUnit=m%2Fs&VisUnit=uPa*s&STUnit=N%2Fm&RefState=DEF

The key features of supercritical fluids is a "fluid" with liquid density but gas viscosity.

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I wonder ...

I thought supercritical steam (where you don't waste heat by doing the unnecessary phase

conversions) was the wave of the future?

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yes

but it is corrosive so maintenance costs rise. supercritical CO2 is nowhere near as corrosive.

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Stop

Unnecessary technical correction

No quite right on " 'supercritical' carbon dioxide, which is just at the point between being a gas and being a liquid". Actually, being superctitical places the material in a temperature/pressure region beyond its critical point, where it behaves in some ways like both a gas and a liquid. For CO2, that means any combination of pressures and temperatures above 31C and 79.2 atm. So, it's more properly "beyond the point where it behaves as only a gas or a liquid".

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Unfortunate name

For something to be connected to a nuclear reactor.

Can just see the nimbies at the planning meeting now - frothing and foaming at the mouth as they get the wrong end of the stick.

Although I guess the likelyhood of them knowing what supercritical in relation to a nuclear reaction may be slim.

I call dibs on the new branding name of TurboGen. I'll take a 0.05% cut of the revenues to license it.

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Alert

That's ok

Finally a good use of all that Panzer Kit we bought for the War on Terror.

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Boffin

NIMBY nimbnuts

They probably hear anything called "critical" and crap themselves anyway. Chernobyl screwed up the nuclear power plant's reputation; ordinary people don't know that nobody is building RBMK reactors anymore, not even Russia.

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Troll

Reputation

"Chernobyl screwed up the nuclear power plant's reputation"

I don't think Three Mile Island and Selafield/Windscale helped much.

Nuclear power is not inherently dangerous. An environment where cost-cutting trumps trumps safety is. The first of the UK's next generation nuclear plants should be built at Battersea to reduce transmission losses and reassure the public as to it's safety. After all, Parliament is just down the river and politicians are unlikely to risk their own health to save a few quid on safety. What could possibly go wrong? See icon.

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City Centre Nukes

Someone once did a faux study on putting a nuclear reactor into Grand Central Station in New York. Turned out that it was not feasible because Grand Central Station is built of granite. The background radiation level was therefore too high to allow the monitoring necessary for the reactor safety standards to be maintained.

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Happy

's true.. Radon levels.

Kraftwerk-Union still haven't finished that plant in Iran neither.. Was wondering about relative property prices, and the ....confidence .. people have in the installed technology.

Compare and contrast to coal powered stations??? Bet the Daily Mail would be interested.

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Headmaster

Good news

...but what's with the inverted commas everywhere?

I'm sure most readers are familiar with the term which pertains to heat!

Is there any purpose of the quotation marks in the title? Is it a quotation? Is it a scare quote to infers the claims are dubious, or simply a lazy writing style lifted from the BBC website?

(Computer techs should know the importance of putting their colons in the right place)

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Coat

the obvious

Yep, on the toilet, like what passes for western civilisation.

Mines the one with dark age survial book in pocket

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Anonymous Coward

Title?

What's with the title?

"New 'supercritical' generators to boost nuclear output by 50%"

First, they're turbines, not generators.

Second, nuclear has little or nothing to do with the article. They're for any thermal power plant.

The only thing I can assume is that the editors wanted to get the words "supercritical" and "nuclear" in the same sentence: shock value leads to clicks.

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Go

honestly?

its an energy generation paper; unless you use the Big Awesome Buzz Words™ you just get lost in the background drone. pretty fucking bossy that its got use for GT and ST plants, though, maybe even a big enough boost for people to stop saying "not economically viable" and start saying "fuck yeah, lets build a big honking CST array"

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Paris Hilton

Ok.. I have questions...

This does sound interesting.

So I have a closed loop system that drives a turbine to generate electricity. So all I need is a really hot side and a really cold side to the loop, right?

So how hot? How cold does it have to be to get it to work?

A solar oven? And then using the earth as a heat sink?

Sounds like a winner to me...

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Yag

Well...

Those solar ovens are called "solar-thermal" in the article.

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SW

“This machine is basically a jet engine running on a hot liquid,” says top boffin Steve Wright

... shortly before playing "You Are Everything" for Sharon in Leicester.

p.s. I also have a famous name, so I'm well-positioned to crack this joke. Nonetheless, I'll get my coat.

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@Good news

The power plants aren't supercritical - only the CO2 is.

It's like 'explosive' CPU performance - you rather hope that the only the performance is explosive - not the CPU!

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Earthquakes in Arkansas

If, as is suspected, pumping stuff into the ground at high pressure causes earthquakes, then the idea about sequestering CO2 is deader than ever. On the other hand, this is good news! We finally have a use for all that CO2 we've been producing--not that there was ever anything wrong with that.

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Anonymous Coward

"We finally have a use for all that CO2 we've been producing"

It's not going anywhere ! It's not consumed

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It's not just 'suspected'

Pumping water into the ground does cause tremors, a deep disposal well in the Rockies (it was dumping nerve gas effluent, nothing to worry about) could turn earthquakes on and off depending on how much crap it was pushing down the pipe.

They're also reasonably common in Iceland around the sites of their geothermal plants where cool water is being returned to the ground after it has given up its heat.

Actually hot basalt plus CO2 is one of the possible ways of getting rid of greenhouse gases. At suitably high temperatures the two react together to form a mineral called palagonite which is perfectly stable.

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They are you

"Meanwhile still heavier hidden electricity taxes and accompanying government inducements might be required if planned levels of wind power are to appear."

My new PV panels on the roof produced more than 22 units (kWhs) in the sunshine yesterday, for which they are paying me about £9.50. That's four times as much as I have to pay to buy electricity from the supplier on my tariff, and I get paid to generate it even when I use it myself (turn on all the appliances while the sun is out).

When I say "they" of course I mean you. This is not subsidised by taxes, but by everyone else that buys electricity. The power companies have to find 15% of their power from renewables, and pay over the odds to get it. Don't think you can get out from under this raw deal either- I have a 25 year contract.

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Your rate will begin to tail off soon though?

I applaud your statement I too wish I wanted to stay in my house for the next ten years ( to break even), had the money and adequately sited roofs to do so. As for not subsidised by taxes who exactly paid for the massive quango driven NFFO?

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Coat

"People are interested in used supercritical CO2 generators....."

Presumably because they are cheaper than new ones?

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Jobs Halo

There you go, we were right

Carbon dioxide cooled reactors, now where have I heard of this before.

Oh I know AGR.

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Anonymous Coward

Oh I know AGR.

NO !

You missed the point - read more carefully

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Jobs Horns

20mW in the back of a transit van?

For Gods sake don't tell Jeremy Clarkson

Headlines: "Transit van out drags Ferrari"

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Anonymous Coward

Re: "Transit van out drags Ferrari"

Been done, decades ago.

Cosworth DFV, racing chassis, Transit(-like) body. Known as Supervan.

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Anonymous Coward

Re: 20mW in the back of a transit van?

He said 20MW not 20mW, but what's a factor of 10^9 here or there.

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Meh

Sounds good at first blush but theres reasons water/steam became the heat transfer agent of choice. Both the US and USSR have tried other liquids with better figures in their nuclear programs (The Sodium reactors on submarines comes to mind) and they always turned out to have the simple drawback of being utter abominations if you considered any situation apart from normal operation. (using the sodium example..if the reactor went cold and you didn't have external heating from another reactor...you were then trying to chip several tons of radioactive metal out from around a nuclear pile..imagine the fun)

Supercritical CO2 sounds cool (just for he sake of annoying global warming people) but what are its characteristics at STP?

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CO2 at STP ?

Err, it's a gas, it just blows away on the wind ...

It's only supercritical if you keep it a >73atm (or something like that).

I suppose a leaky pipe might be a bit scary at that pressure, but otherwise, it's just carbon dioxide

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CO2

And it will be in the secondary loop - so, not radioactive.

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Anonymous Coward

What a cobbled togther piece of junk.

Another Dodgy El Reg Environment Story.

50% more power.

Where is the source for this, what its based on. Links to places ranting, but not the facts.

Yes Nuke turbines are inefficient. But some are antiques, some are not.

Your posting about lab trials. When they get the commercial go-ahead, please tell us. I understand the Russians have had several goes at this kind of turbine.

btw, the amen "eco" friendly ones don't need this efficiency boost, as means they use to generate leccy are efficient already. Thou, you can argue about what efficiency measure you want to take, pretty sure you will.

Folks when you read the reg, think first.

basically an article of polyfilla. cack.

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When you comment, think first...

Better efficiency that current designs - so no matter what the current efficiency, even if very good, these are better - surely that is a good thing? And the whole purpose of the story was to indicate that the problems encountered by previous attempts have been overcome.

It would be nice to see references, but, where are YOUR references to dispute what was written - it cuts both ways.

Articles about new technology will always talk about prototypes - what the point of talking about it once it all installed and working - it's not new technology then.

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FAIL

You got derp on your herp

Sorry sunshine, you don't get to lecture us on reading style and comprehension and then use 'efficient' without a modifier. Stating something is efficient as an absolute here isn't going to fly; The green plants are efficient, are they, 100%? that's a helluva story, stop the presses.

Folks; when you post on the reg... Think first.

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Good for geothermal

This could make many more geothermal reserves viable for energy production where it is hard to get either steam or very high temperature water out of the wells (I'm thinking Cornwall here), but it might also boost the efficiency of the high temperature fields in places like Iceland and the Philippines by allowing them to extract more energy.

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Stop

laws of thermodynamics

Given knowledge of hot and cold source temperatures, the laws of thermodynamics will tell you the maximum percentage of heat energy which can be extracted. The colder your cold sink and the hotter your hot source relative to how far above absolute zero your cold source is, the closer to 100% energy conversion you can theoretically get.

Large fossil fuel plant efficiencies are constrained due to the need to avoid melting known materials for heat exchangers and because cold sinks have to be a few hundred C above absolute zero.

Last time I looked at these numbers for nuclear, these were running at much lower thermodynamic efficiencies than fossil plants, due to the obvious reason that you don't want to run the reactor too hot for its safety. Of course in the fossil case, you could use the waste heat for district heating, but people generally prefer a larger distance between their hot water pipes and the nearest nuclear power plant.

So how does this unsupported claim of a 50% improvement change these constraints, or is Lewis really just having yet another tilt at windmills ?

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Fact

"Of course in the fossil case, you could use the waste heat for district heating, but people generally prefer a larger distance between their hot water pipes and the nearest nuclear power plant."

In the Soviet Union they bred carp in the cooling ponds, then ate them. That was to demonstrate the environmental safety of nuclear power stations.

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Yag
Troll

carps in cooling pond?

Pripyat river is not a cooling pond!

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Cheap electricity?

OK the real story behind this seems to be as follows: standard generation kit uses steam turbines, which start with liquid water, add heat to turn it to steam (passing through the phase change from liquid to gas which is particularly large for water), then cycle the steam back into water using cooling towers. This wastes the energy needed to effect the liquid to gas phase change in water; the ONLY reason to use water as a working fluid here is that it is cheap, plentiful and non-polluting.

If you use a closed-cycle engine working with highly compressed CO2, then the engine will have a hot side, a cold side (think honking great water-cooled system) and a turbine in the middle. The denser the working fluid the more energy can be extracted from from it as it passes through the turbine; the advantage to using CO2 is that you can turn it into a supercritical fluid (which acts like a liquid and a gas at once) at relatively low temperatures and pressures, and under these conditions the CO2 is not particularly corrosive to standard industrial steels. CO2 is also not particularly toxic, leaks are not a major concern and humans readily detect and avoid CO2 without special monitoring equipment, at least at low concentrations.

Combine this with a LFTR thorium reactor and you'd have an effective way of harvesting heat from a nuclear reactor which wouldn't be of much use for producing nuclear weapons, and wouldn't generate much high-level nuclear waste either. Better yet, since long-distance electrical wiring is so efficient, we wouldn't actually need very many new nuclear reactors to supply the country's electricity needs.

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