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In message , André Coutanche
writes
The Natural Philosopher wrote:
Tim Lamb wrote:

I know nothing about gas turbines.

I know a LITTLE more, but not enough..

That stirred a long disused neurone, which said 'CCGT'. That led to
http://en.wikipedia.org/wiki/Combined_cycle, and one of its references,
http://memagazine.asme.org/Web/Effic...by_Numbers.cfm . So, yes,
efficiencies can be achieved which appear at first glance to break the laws
of thermodynamics ...

Ah. All is explained.

ISTR the idea of mag. thermo dynamics was to withdraw energy (DC) from
the ionised gas stream in a conventional boiler.

regards
--
Tim Lamb

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[email protected] wrote:


"The Natural Philosopher" wrote in message
...

well with a typical power station being somewhere upwards of a Gw, and
our total energy needs as a country running at an estimated 300GW, I
cant see those making a huge difference to anything.

I can, hydro electric are easy to control and respond quickly.
Run them at the bare minimum and you can turn them up to smooth supply
during peaks.
Pretty much like the pumped hydro stations but not as big.

ISTR that Dinorwig could run from zero to full power in about 2 minutes.
Any hydro scheme should be able to do that too.

--

People like you are the reason people like me have to take medication.

?John Wright

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The Natural Philosopher wrote:
J G Miller wrote:
On Sun, 27 Sep 2009 22:26:11 +0100, [email protected] wrote:

We have hydro plants on streams that can generate a couple kilowatts

Sounds like Scottish Power generate more than a *couple of kilowatts*
to me
from hydro electric schemes --

Lanark Hydro Electric Scheme 17 MW


About the same as a big diesel generator. Enough to run one electric
train line maybe..

Depends on the electric train. Eurostars IIRC use about 13Mw on 25KV AC
- much less in Belgium or on third rail. (Eurostars are *very* long)
Class 91 trains on the ECML use about 5Mw.

Pendolinos are heavy and "built like a tank" according to Richard
Branson :-) and use just under 6Mw. Class 92s about the same.

The highest power electric trains are the Eurotunnel shuttles, with two
Class 9/8s they will use around 15MW.

So more than one unless you want loads of Eurostars.

--

People like you are the reason people like me have to take medication.

John Wright

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The Natural Philosopher wrote:
Java Jive wrote:
On Sun, 27 Sep 2009 21:31:57 +0100, The Natural Philosopher
wrote:
There is nothing centralised about the grid.

Power generation is centralised.

On a level UK playing field, we have plenty of wind and rain, some
sun, and no uranium ore.
WE have totally inadequate wind rain and places to generate hydro pwer.

The field is tilted way against nuclear and way pro wind, that's all.
Whereas historically it has been the other way about.
It has not.

It was tilted massively towards big centralised power generation in
the post-war years, with large government investments in places like
Windscale and Dounreay, and through the CEGB commissioning the first
rounds of nuclear power stations.


Windscale and Douunreay were weapons production facilities thinly
disguised as power stations.

Chapelcross rather than Dounreay I think. What you need for plutonium
production is a fast turn round natural uranium reactor. Hence Calder
Hall and Chapelcross. These two were always owned by UKAEA rather than
whatever organisation ended up with the other Magnox reactors.

AFAIK Dounreay was always a research establishment.

--

People like you are the reason people like me have to take medication.

?John Wright

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On Wednesday, October 7th, 2009 08:52:16 +0100, Tim Lamb suggested:

Using waste heat for space heating only works if you have generating
plant in the middle of towns and you don't have warm summers:-)

Metz, Lorraine has warm (compared to England) summers and the CHP there,
one of the oldest in France has worked efficiently and successfully.

http://www.uem-metz.FR/site/_activites_chauffage.php

In 2005 UEM added a second network of 15 km and 88 sub-stations,
with 300 clients.

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J G Miller wrote:
On Sun, 27 Sep 2009 16:33:02 +0000, Richard Tobin wrote:

In the standard model, protons don't decay.

Is Wikipedia correct in its assertion that

QUOTE
Proton decay has not been observed.
There is currently no evidence that proton decay occurs.
UNQUOTE

I would say that is true and correct whatever theory you happen to
believe in.

--

People like you are the reason people like me have to take medication.

John Wright

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On Wed, 07 Oct 2009 14:30:01 +0100, John Wright
wrote:

snip

ISTR that Dinorwig could run from zero to full power in about 2 minutes.
Any hydro scheme should be able to do that too.

The reality is rather more impressive:
http://www.fhc.co.uk/dinorwig.htm

"Synchronised and spinning-in-air emergency load pick-up rate from
standby: 0 to 1,320 MW in 12 seconds"

One of the design briefs for the station was that it was to be capable
of supplying power quicker than gas-turbine plant, and it was designed
accordingly. This will not generally be true of conventional hydro
schemes.

Brian

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"John Wright" wrote in message
...
[email protected] wrote:


"The Natural Philosopher" wrote in message
...

well with a typical power station being somewhere upwards of a Gw, and
our total energy needs as a country running at an estimated 300GW, I
cant see those making a huge difference to anything.

I can, hydro electric are easy to control and respond quickly.
Run them at the bare minimum and you can turn them up to smooth supply
during peaks.
Pretty much like the pumped hydro stations but not as big.

ISTR that Dinorwig could run from zero to full power in about 2 minutes.
Any hydro scheme should be able to do that too.

With the minor problem of how to refill the dam.

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Brian wrote:
On Wed, 07 Oct 2009 14:30:01 +0100, John Wright
wrote:

snip

ISTR that Dinorwig could run from zero to full power in about 2 minutes.
Any hydro scheme should be able to do that too.

The reality is rather more impressive:
http://www.fhc.co.uk/dinorwig.htm

"Synchronised and spinning-in-air emergency load pick-up rate from
standby: 0 to 1,320 MW in 12 seconds"

One of the design briefs for the station was that it was to be capable
of supplying power quicker than gas-turbine plant, and it was designed
accordingly. This will not generally be true of conventional hydro
schemes.

Though there is no reason why it need not be.

--

People like you are the reason people like me have to take medication.

?John Wright

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Derek Geldard wrote:
On Wed, 23 Sep 2009 10:02:01 +0100 (BST), "Dave Liquorice"
wrote:

On Wed, 23 Sep 2009 03:03:15 +0100, Derek Geldard wrote:

Not true, in fact. All radioactive isotopes decay according to their
half lives. When they're gone, they're gone.
"Half life", the period of time it takes for half of the orginal
substance to have decayed. After that time it's another equal period
for the next half to decay, still leaving you with 1/4 of the orginal
amount.

However it doesn't take many half lives for activity to decay to a
level lower than the natural background, whence it will become
undetectable - and it will still keep on decaying.

In the medical isotope industry it is reckoned that all radiactivity
may be taken to have ceased after 6 half lives. If the half life is 6
hours (TC99m) then effectively it's all gone after 36 hours and a big
dose can safely be injected into a patient for a radionuclide scan.
After 10 half lives the activity is down to about 0.5 per million of
what you started with.

If it's 12,000 years it will be rather longer, but decay it will.

An isotope also has a bilogical half life which is the rate that it
would be eliminated from the body by normal bodily functions.

Of course it depends on the substance how long the half life is, they
vary from seconds to thousands of years but most are fairly short and
the level of radiation decreases over time as well. The nature of the
radiation is important as well, alpha particles are easyly stopped
for example.

Common misconception, along with "If an isotope has a long half life
it's not very radioactive", -erm no 1 millicurie is 1 millicurie .

Very true, but pound for pound there is less radiation from something
with a long half life than from a short one. Hence natural uranium is
normal, but plutonium is warm to the touch. 1 millicurie of each would
be very different in physical weight or even mass.

NB. if high energy Alpha emitting isotopes are absorbed into the body
they do tremendous damage at the cellular level because alpha
particles are electrically charged and lose all their energy over a
very short distance (hence the low penetrating capability). The most
damage is caused when a speck of alpha emitting material lodges in the
body and goes on year in year out irradiating the same tiny volume of
body tissue, cell damage leading to cancer is very likely.

Most alpha emitters also emit beta and/or gamma radiation as well. As
you say they have to be absorbed into the body to create a real danger.

--

People like you are the reason people like me have to take medication.

?John Wright

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In message , J G Miller
writes
On Wednesday, October 7th, 2009 08:52:16 +0100, Tim Lamb suggested:

Using waste heat for space heating only works if you have generating
plant in the middle of towns and you don't have warm summers:-)

Metz, Lorraine has warm (compared to England) summers and the CHP there,
one of the oldest in France has worked efficiently and successfully.

http://www.uem-metz.FR/site/_activites_chauffage.php

In 2005 UEM added a second network of 15 km and 88 sub-stations,
with 300 clients.

My schoolboy French was stretched until I found the translate button:-)

They don't mention overall efficiency either Winter or Summer but I note
hot water is available for bathing etc.

regards

--
Tim Lamb

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On Wed, 07 Oct 2009 17:27:10 +0100, Brian wrote:

"Synchronised and spinning-in-air emergency load pick-up rate from
standby: 0 to 1,320 MW in 12 seconds"

That isn't particulary impressive, the switch from full pumping to
full output is the impressive figure, as you have to completely
reverse the direction of rotation of the turbines. Can I find that
fugure now... but it's well less than a minute.

One of the design briefs for the station was that it was to be capable
of supplying power quicker than gas-turbine plant, and it was designed
accordingly. This will not generally be true of conventional hydro
schemes.

They can still go from zero to online full output in pretty short
order, ie. a couple of minutes.

No sure how fast you can bring up a gas turbine set. All the gas
turbines I've come across have to warmed up for several minutes
before you can wind up the output and that's little ones like you
find in helicopters.

--
Cheers
Dave.

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John Wright wrote:
Brian wrote:
On Wed, 07 Oct 2009 14:30:01 +0100, John Wright
wrote:

snip

ISTR that Dinorwig could run from zero to full power in about 2
minutes. Any hydro scheme should be able to do that too.

The reality is rather more impressive:
http://www.fhc.co.uk/dinorwig.htm

"Synchronised and spinning-in-air emergency load pick-up rate from
standby: 0 to 1,320 MW in 12 seconds"

One of the design briefs for the station was that it was to be capable
of supplying power quicker than gas-turbine plant, and it was designed
accordingly. This will not generally be true of conventional hydro
schemes.

Though there is no reason why it need not be.

the key to fast load pickup is to have a genny spinning and synched to
the mains frequency and phase locked, being driven BY the mains, or at
least idling more or less in neutral. Then feed in steam or water or
whatever to make it contribute.

Its an alarming thought, but what keeps the mains steady through all the
short term fluctuations is nothing more nor les than the rotational
inertia of a hundred turbine shafts..

something you wont have with windmills, which are not phase locked
mechanically.

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Dave Liquorice wrote:
On Wed, 07 Oct 2009 17:27:10 +0100, Brian wrote:

"Synchronised and spinning-in-air emergency load pick-up rate from
standby: 0 to 1,320 MW in 12 seconds"

That isn't particulary impressive, the switch from full pumping to
full output is the impressive figure, as you have to completely
reverse the direction of rotation of the turbines. Can I find that
fugure now... but it's well less than a minute.

One of the design briefs for the station was that it was to be capable
of supplying power quicker than gas-turbine plant, and it was designed
accordingly. This will not generally be true of conventional hydro
schemes.

They can still go from zero to online full output in pretty short
order, ie. a couple of minutes.

No sure how fast you can bring up a gas turbine set. All the gas
turbines I've come across have to warmed up for several minutes
before you can wind up the output and that's little ones like you
find in helicopters.

thats why they sit on hot standby, wasting fuel spinning so that the
lights don't go out in Denmark when the wind drops.

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On Thu, 1 Oct 2009 16:19:49 +0100, "Bill Wright"
wrote:


"Java Jive" wrote in message
.. .
I wonder how long it would take to repay the energy invested in
building it, how long it would take to silt up, and what, if any, the
solution to such a problem might be. These points would need to be
very carefully assessed.

Oh they'll do that all right. They're very clever men. We don't have
cock-ups in this country.

Bill


All coils will be wound with ****z wire.

Derek

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On Thu, 17 Sep 2009 16:01:59 +0100, The Natural Philosopher
wrote:


natural radon is the greatest source of radioactive related deaths in
the country, by IIRC a factor of several thousand over the nuclear industry.

Bizarrely enough, or so I believe, coal fired power stations actually
emit more "radiation" than nuclear due to the radioactive content of
the coal

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On Thu, 17 Sep 2009 16:01:59 +0100, The Natural Philosopher
wrote:

Happy birthday, I have now put my glasses on and realised this thread
was from a year ago

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Albert Ross wrote:
On Thu, 17 Sep 2009 16:01:59 +0100, The Natural Philosopher
wrote:


natural radon is the greatest source of radioactive related deaths in
the country, by IIRC a factor of several thousand over the nuclear industry.

Bizarrely enough, or so I believe, coal fired power stations actually
emit more "radiation" than nuclear due to the radioactive content of
the coal

This is apparently so.

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Albert Ross wrote:
On Thu, 17 Sep 2009 16:01:59 +0100, The Natural Philosopher
wrote:

Happy birthday, I have now put my glasses on and realised this thread
was from a year ago

Still thoroughly relevant today, with the data emerging about how
ghastly and useless wind and solar power really are, and the government
in a flat spin over carbon floor pricing.

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On Tue, 21 Sep 2010 19:29:54 +0100, Ericp
wrote:

On Tue, 21 Sep 2010 11:39:22 +0100, Albert Ross
wrote:

On Thu, 17 Sep 2009 16:01:59 +0100, The Natural Philosopher
wrote:

Happy birthday, I have now put my glasses on and realised this thread
was from a year ago

TFFT!

I have been trolling up and down the past months looking for it and
was about to complain to the provider about missing threads. :))

I should do some archiving, I just found a new thread attached to one
from years back which prompted me to look through the rest of the
group seeing what else I missed, this was a false positive.

Still available on Giganews, they have about seven years of usenet
archived now and about two years of binaries

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"Albert Ross" wrote in message
...
On Thu, 17 Sep 2009 16:01:59 +0100, The Natural Philosopher
wrote:


natural radon is the greatest source of radioactive related deaths in
the country, by IIRC a factor of several thousand over the nuclear
industry.

Bizarrely enough, or so I believe, coal fired power stations actually
emit more "radiation" than nuclear due to the radioactive content of
the coal

I think that the big difference is what they capable of emitting, not what
the actually emit.

You can pile coal waste up in a heap and build a local park on it. You
can't do that with nuclear waste.


tim

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On 23 Sep, 12:57, "tim...." wrote:
"Albert Ross" wrote in message

...

On Thu, 17 Sep 2009 16:01:59 +0100, The Natural Philosopher
wrote:

natural radon is the greatest source of radioactive related deaths in
the country, by IIRC a factor of several thousand over the nuclear
industry.

Bizarrely enough, or so I believe, coal fired power stations actually
emit more "radiation" than nuclear due to the radioactive content of
the coal

I think that the big difference is what they capable of emitting, not what
the actually emit.

You can pile coal waste up in a heap and build a local park on it. *You
can't do that with nuclear waste.

tim

One more post for 1000!

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In article , tim.... wrote:

You can pile coal waste up in a heap and build a local park on it.

Though you do have to be a bit careful about that:
http://en.wikipedia.org/wiki/Fly_ash..._contamination

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Albert Ross wrote:

Bizarrely enough, or so I believe, coal fired power stations actually
emit more "radiation" than nuclear due to the radioactive content of
the coal

Indeed, but it is large volumes of extremely low level radiation,
rather than tiny volumes of high level radiation. That's the problem;
the latter needs special handling and storage.

SteveT

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tim.... wrote:
"Albert Ross" wrote in message
...
On Thu, 17 Sep 2009 16:01:59 +0100, The Natural Philosopher
wrote:


natural radon is the greatest source of radioactive related deaths in
the country, by IIRC a factor of several thousand over the nuclear
industry.
Bizarrely enough, or so I believe, coal fired power stations actually
emit more "radiation" than nuclear due to the radioactive content of
the coal

I think that the big difference is what they capable of emitting, not what
the actually emit.

You can pile coal waste up in a heap and build a local park on it. You
can't do that with nuclear waste.


You could, easily.

And it would be no worse than the ash.

But legally ash isn't classed as radioactive waste (though it is) and
anything out of a nuclear power station is (though most of it is barely
radioactive at all)


Only high level waste needs special treatment, and thats reporocessed to
make more fuel.



tim

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Steve Thackery wrote:
Albert Ross wrote:

Bizarrely enough, or so I believe, coal fired power stations actually
emit more "radiation" than nuclear due to the radioactive content of
the coal

Indeed, but it is large volumes of extremely low level radiation, rather
than tiny volumes of high level radiation. That's the problem; the
latter needs special handling and storage.


Mix it with enough random rubbish, and its high volume low level :-)

Apart from fuel rids and the like, there is not much else out of a
reactor that is radioactive.

Until to take it to bits. Which is why they are preferably just filled
up with concrete and left for a couple of hundred years.



SteveT

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Albert Ross wrote:
Bizarrely enough, or so I believe, coal fired power stations actually
emit more "radiation" than nuclear due to the radioactive content of
the coal

"Steve Thackery" wrote: Indeed, but it is large
volumes of extremely low level radiation, rather than tiny volumes of high
level radiation. That's the problem; the latter needs special handling and
storage.


From my backyard I can see four of the eight reactor buildings that at one
time made up the worlds largest nuclear power plant. I have yet to hear of
any spikes in the number of incidences of cancers in the local population
and, I have lived here pretty much since the plant went into operation some
30 years ago. Admittedly there are only four of the reactors still in
operation these days.
There is a monitoring agency that keeps an eye on the local health
situation.
Truebrit.

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On 23/09/2010 18:39, Steve Thackery wrote:
Albert Ross wrote:

Bizarrely enough, or so I believe, coal fired power stations actually
emit more "radiation" than nuclear due to the radioactive content of
the coal

Indeed, but it is large volumes of extremely low level radiation, rather
than tiny volumes of high level radiation. That's the problem; the
latter needs special handling and storage.

SteveT



That's easily dealt with. Let's take the fission waste, grind it up
small, and scatter it over the Sahara Desert. We can then collect up
the sand, which will be no more radioactive than the fly ash.

Or we could stick it in a little hole out of the way somewhere.

Andy

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On Thu, 23 Sep 2010 19:18:45 +0100, The Natural Philosopher wrote:
Steve Thackery wrote:
Albert Ross wrote:

Bizarrely enough, or so I believe, coal fired power stations actually
emit more "radiation" than nuclear due to the radioactive content of
the coal

Indeed, but it is large volumes of extremely low level radiation, rather
than tiny volumes of high level radiation. That's the problem; the
latter needs special handling and storage.


Mix it with enough random rubbish, and its high volume low level :-)

Apart from fuel rids and the like, there is not much else out of a
reactor that is radioactive.

Until to take it to bits. Which is why they are preferably just filled
up with concrete and left for a couple of hundred years.

Depends whether you count the by-products of reprocessing, which
adds up to quite a bit. Plus the low-level radioactive waste such
as prtective clothing & irradiated equipment that gets zapped
during maintenance.

--
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