OT: Drax to be turned off whenever it's "too" windy or sunny

<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

Timatmarford

2025-02-10 10:51:53 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

Silly question but, why do the media always show pictures of the cooling
towers rather than the flues which might actually emit some CO2?

Jeff Gaines

2025-02-10 11:05:53 UTC

Post by Timatmarford

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

Silly question but, why do the media always show pictures of the cooling
towers rather than the flues which might actually emit some CO2?

Foe the same reason they always show a picture of the Royal Exchange when
discussing the Bank of England, ignorance.

--
Jeff Gaines Dorset UK
I take full responsibility for what happened - that is why the person that
was responsible went immediately.
(Gordon Brown, April 2009)

Andrew

2025-02-10 16:27:54 UTC

Post by Jeff Gaines

Post by Timatmarford

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

Silly question but, why do the media always show pictures of the
cooling towers rather than the flues which might actually emit some CO2?

Foe the same reason they always show a picture of the Royal Exchange
when discussing the Bank of England, ignorance.

And gnarly, wrinkled hands when discussing pensions

brian

2025-02-10 13:39:31 UTC

Post by Timatmarford

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

Silly question but, why do the media always show pictures of the
cooling towers rather than the flues which might actually emit some CO2?

Here you are, With one of the blokes that built it.

Https://www.yorkpress.co.uk/resources/images/9910821.

It doesn't look impressive, given it's not belching smoke or water
vapour like the cooling towers

However it is the tallest chimney in the UK . An up-draught to die for.

Brian

--
Brian Howie

Adrian

2025-02-10 14:29:25 UTC

Post by brian
Here you are, With one of the blokes that built it.
Https://www.yorkpress.co.uk/resources/images/9910821.
It doesn't look impressive, given it's not belching smoke or water
vapour like the cooling towers
However it is the tallest chimney in the UK . An up-draught to die for.

When I were a lad, our village photographer had the opportunity to get
some pictures from the top of the chimney (around the time it was
built), which he duly displayed in his shop window. Rather impressive,
but I don't think I would have been comfortable joining him.

Adrian
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Pancho

2025-02-10 12:51:48 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

There doesn't seem anything intrinsically wrong with that.

Obviously, we want Drax when there isn't enough wind or solar, so the
profit it makes during those periods has to cover the fact it isn't
making money when wind and solar are available.

We all know that is the basic economics of having dispatchable
generation stations to cover peak periods.

The worrying thing I heard the other day, which I don't have a cite for,
is that Labour recently cancelled a planned review/inquiry/analysis of
the holistic costs of different electrical generation scenarios.

Andy Burns

2025-02-10 13:32:39 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

There doesn't seem anything intrinsically wrong with that.

I didn't say it was wrong, they currently cream-in the dubious biomass
subsidies at times when solar and wind are operating above their long
term averages.

Post by Pancho
The worrying thing I heard the other day, which I don't have a cite for,
is that Labour recently cancelled a planned review/inquiry/analysis of
the holistic costs of different electrical generation scenarios.

Welsh planners apparently put preserving Yaki Dah above replacing Wylfa

Andrew

2025-02-10 16:29:03 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

There doesn't seem anything intrinsically wrong with that.

I didn't say it was wrong, they currently cream-in the dubious biomass
subsidies at times when solar and wind are operating above their long
term averages.

But the DRX share price was up over 5% earlier, now about 3% up

The Natural Philosopher

2025-02-10 21:37:32 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

There doesn't seem anything intrinsically wrong with that.
Obviously, we want Drax when there isn't enough wind or solar, so the
profit it makes during those periods has to cover the fact it isn't
making money when wind and solar are available.
We all know that is the basic economics of having dispatchable
generation stations to cover peak periods.
The worrying thing I heard the other day, which I don't have a cite for,
is that Labour recently cancelled a planned review/inquiry/analysis of
the holistic costs of different electrical generation scenarios.

Of course they did. It's not fact driven, its profit and ideology driven
politics

--
"When one man dies it's a tragedy. When thousands die it's statistics."

Josef Stalin

SteveW

2025-02-10 23:01:28 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

There doesn't seem anything intrinsically wrong with that.
Obviously, we want Drax when there isn't enough wind or solar, so the
profit it makes during those periods has to cover the fact it isn't
making money when wind and solar are available.
We all know that is the basic economics of having dispatchable
generation stations to cover peak periods.
The worrying thing I heard the other day, which I don't have a cite for,
is that Labour recently cancelled a planned review/inquiry/analysis of
the holistic costs of different electrical generation scenarios.

The question is, what's the effect, practically and economically, of
taking a thermal power plant on and off line, instead of running it
throughout and varying the output a little?

Pancho

2025-02-11 00:44:58 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

There doesn't seem anything intrinsically wrong with that.
Obviously, we want Drax when there isn't enough wind or solar, so the
profit it makes during those periods has to cover the fact it isn't
making money when wind and solar are available.
We all know that is the basic economics of having dispatchable
generation stations to cover peak periods.
The worrying thing I heard the other day, which I don't have a cite
for, is that Labour recently cancelled a planned review/inquiry/
analysis of the holistic costs of different electrical generation
scenarios.

The question is, what's the effect, practically and economically, of
taking a thermal power plant on and off line, instead of running it
throughout and varying the output a little?

Indeed, that's why I mentioned the review.

I heard it in a YouTube interview of Kathryn Porter by Freddie Sayers of
UnHerd, "Will blackouts come to Britain?".

She makes a comment that towards the end of their term the Conservatives
had been asking probing questions about the costs of renewables, but
that the work being done to establish these costs had now been suspended.

She makes the comment at 36:40 in the video.

In general, the interview is just basic stuff, rather than anything
profound. FWIW, she agrees with my assertion that we should build
traditional big Nuclear Stations rather than SMR, so obviously I like
her :-).

The Natural Philosopher

2025-02-12 14:53:11 UTC

Post by Pancho
In general, the interview is just basic stuff, rather than anything
profound. FWIW, she agrees with my assertion that we should build
traditional big Nuclear Stations rather than SMR, so obviously I like
her 🙂.

All other things being equal, yes we should BUT all other things are not
equal

The politics and planning of getting big power stations built adds
massive amounts to the cost and they cannot be built close to where
demand is. This adds infrastructure cost and massive pylons across the
landscape.

We have signed up to retain harmonisation with Euratom which was a huge
mistake so there is no easy way to avoid the cost of meeting EU
regulatory standards
The point about SMRs is they may not be as ultimately efficient but they
can be installed in 3 years, not 20. And close to where the power is
needed.

Neither the tTories nor Labour have the guts to break away from the Eu
regulations, so SMRS are the only way to lessen their impact at this
point in time. and certainly having factory built modules means from
planning to grid connections will be mighty fast - not much different to
a gas power station

--
It’s easier to fool people than to convince them that they have been fooled.
Mark Twain

charles

2025-02-12 17:00:01 UTC

We used to build them where they were needed: Battersea, Bankside & Lot's
Road in Central London for a start.

--
from KT24 in Surrey, England - sent from my RISC OS 4té²
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

The Natural Philosopher

2025-02-13 04:09:41 UTC

We used to build them where they were needed: Battersea, Bankside & Lot's
Road in Central London for a start.

Imagine sticking a 5GW nuclear power station in central london now.

Cant even get a third runway on heathrow after 30 years

--
You can get much farther with a kind word and a gun than you can with a
kind word alone.

Al Capone

Andrew

2025-02-13 22:19:07 UTC

We used to build them where they were needed: Battersea, Bankside & Lot's
Road in Central London for a start.

That was before Mr Tesla 'invented' AC power distribution allowing
them to be located away from where the electrons are needed.

The Natural Philosopher

2025-02-14 03:11:29 UTC

We used to build them where they were needed: Battersea, Bankside & Lot's
Road in Central London for a start.

That was before Mr Tesla 'invented' AC power distribution allowing
them to be located away from where the electrons are needed.

Your grasp of electrics is somewhat quaint, to say the least.

Battersea power station was first built in 1929
Tesla's AC machines were built in the late 1880s.

Long distance power transmission costs money. That fact has nothing to
do with whether it's AC or DC.

--
The theory of Communism may be summed up in one sentence: Abolish all
private property.

Karl Marx

Andrew

2025-02-14 11:59:46 UTC

We used to build them where they were needed: Battersea, Bankside & Lot's
Road in Central London for a start.

That was before Mr Tesla 'invented' AC power distribution allowing
them to be located away from where the electrons are needed.

Your grasp of electrics is somewhat quaint, to say the least.
Battersea power station was first built in 1929
Tesla's AC machines were built in the late 1880s.
Long distance power transmission costs money. That fact has nothing to
do with whether it's AC or DC.

You must be heading for dementia then.
Long distance AC transmission was actually *possible* ~100
years ago, unlike long distance DC transmission which has
now only become possible in the 'modern' era

Pancho

2025-02-14 12:41:30 UTC

Post by Andrew
That was before Mr Tesla 'invented' AC power distribution allowing
them to be located away from where the electrons are needed.

Your grasp of electrics is somewhat quaint, to say the least.
Battersea power station was first built in 1929
Tesla's AC machines were built in the late 1880s.
Long distance power transmission costs money. That fact has nothing
to do with whether it's AC or DC.

a) HVDC was also possible in the 1880s, using motor-generators (just
uneconomic),
b) TNP's point was that long distance power transmission is expensive
for either DC or AC.

I'm not convinced by the economics of local generation, in general, in
terms of an overall optimal economic solution, but there is no point in
denying long distance transmission costs money.

The Natural Philosopher

2025-02-14 13:27:25 UTC

We used to build them where they were needed: Battersea, Bankside & Lot's
Road in Central London for a start.

That was before Mr Tesla 'invented' AC power distribution allowing
them to be located away from where the electrons are needed.

Your grasp of electrics is somewhat quaint, to say the least.
Battersea power station was first built in 1929
Tesla's AC machines were built in the late 1880s.
Long distance power transmission costs money. That fact has nothing
to do with whether it's AC or DC.

Don't be silly. Long distance DC transmissions has always been *possible*.

But that is irrelevant., You said that the switch to AC caused power
stations to be remotely located. I showed how stupid a statement that
was, since Battersea was built 40 years or more AFTER AC was common
place, right inside London.

Because it was cost effective to do it. Demand and generation not
separated by massive cables

Power station location is a cost benefit optimisation between where
demand is, where fuel or energy source is and cost of transmission, and
of course politics.
The ideal place to shove a 5GW nuclear power station is right up Sadiqs
arse, in Battersea.

River cooling, zero transmission losses and costs and a network of
district heating pipes already in place.
--
If you tell a lie big enough and keep repeating it, people will
eventually come to believe it. The lie can be maintained only for such
time as the State can shield the people from the political, economic
and/or military consequences of the lie. It thus becomes vitally
important for the State to use all of its powers to repress dissent, for
the truth is the mortal enemy of the lie, and thus by extension, the
truth is the greatest enemy of the State.

Joseph Goebbels

Andrew

2025-02-16 19:26:25 UTC

We used to build them where they were needed: Battersea, Bankside & Lot's
Road in Central London for a start.

That was before Mr Tesla 'invented' AC power distribution allowing
them to be located away from where the electrons are needed.

Your grasp of electrics is somewhat quaint, to say the least.
Battersea power station was first built in 1929
Tesla's AC machines were built in the late 1880s.
Long distance power transmission costs money. That fact has nothing
to do with whether it's AC or DC.

I was browsing in Currys yesterday for a DECT phone and I failed
to see any fridges, cookers, washing m/c's, air-fryers, microwaves,
or electric heaters that only ran on DC. I wonder why ?.

The Natural Philosopher

2025-02-16 20:52:27 UTC

We used to build them where they were needed: Battersea, Bankside & Lot's
Road in Central London for a start.

That was before Mr Tesla 'invented' AC power distribution allowing
them to be located away from where the electrons are needed.

Your grasp of electrics is somewhat quaint, to say the least.
Battersea power station was first built in 1929
Tesla's AC machines were built in the late 1880s.
Long distance power transmission costs money. That fact has nothing
to do with whether it's AC or DC.

I was browsing in Currys yesterday for a DECT phone and I failed
to see any fridges, cookers, washing m/c's, air-fryers, microwaves,
or electric heaters that only ran on DC. I wonder why ?.

Because only a stupid fucking idiot would persist in trying to win an
argument he lost 6 posts back

--
"In our post-modern world, climate science is not powerful because it is
true: it is true because it is powerful."

Lucas Bergkamp

Andrew

2025-02-17 18:13:00 UTC

We used to build them where they were needed: Battersea, Bankside & Lot's
Road in Central London for a start.

That was before Mr Tesla 'invented' AC power distribution allowing
them to be located away from where the electrons are needed.

Your grasp of electrics is somewhat quaint, to say the least.
Battersea power station was first built in 1929
Tesla's AC machines were built in the late 1880s.
Long distance power transmission costs money. That fact has
nothing to do with whether it's AC or DC.

I was browsing in Currys yesterday for a DECT phone and I failed
to see any fridges, cookers, washing m/c's, air-fryers, microwaves,
or electric heaters that only ran on DC. I wonder why ?.

Because only a stupid fucking idiot would persist in trying to win an
argument he lost 6 posts back

Talking to yourself again then

crn

2025-02-14 14:00:14 UTC

Post by charles
We used to build them where they were needed: Battersea, Bankside &
Lot's Road in Central London for a start.

That was before Mr Tesla 'invented' AC power distribution allowing
them to be located away from where the electrons are needed.

Your grasp of electrics is somewhat quaint, to say the least.
Battersea power station was first built in 1929 Tesla's AC machines
were built in the late 1880s.
Long distance power transmission costs money. That fact has nothing to
do with whether it's AC or DC.

You must be heading for dementia then.
Long distance AC transmission was actually *possible* ~100 years ago,
unlike long distance DC transmission which has now only become possible
in the 'modern' era

Cabora Basa to Pretoria has been around for a long while.
Depends on what you call "modern"
+500 and -500 Kvolts on separate pylons about a mile apart which means
that the inverter station outside of Pretoria gets to play with a million
volts.

mm0fmf

2025-02-14 18:52:35 UTC

Post by crn
Pretoria gets to play with a million
volts.

I do picture Dr. Evil when I read your million volts line. :-)

Nick Finnigan

2025-02-11 08:57:19 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

There doesn't seem anything intrinsically wrong with that.
Obviously, we want Drax when there isn't enough wind or solar, so the
profit it makes during those periods has to cover the fact it isn't
making money when wind and solar are available.
We all know that is the basic economics of having dispatchable generation
stations to cover peak periods.
The worrying thing I heard the other day, which I don't have a cite for,
is that Labour recently cancelled a planned review/inquiry/analysis of
the holistic costs of different electrical generation scenarios.

The question is, what's the effect, practically and economically, of taking
a thermal power plant on and off line, instead of running it throughout and
varying the output a little?

Note that Drax has 6 boilers and turbines, so 'a little' is probably 17%.

Theo

2025-02-11 12:07:42 UTC

Post by Nick Finnigan

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

There doesn't seem anything intrinsically wrong with that.
Obviously, we want Drax when there isn't enough wind or solar, so the
profit it makes during those periods has to cover the fact it isn't
making money when wind and solar are available.
We all know that is the basic economics of having dispatchable generation
stations to cover peak periods.
The worrying thing I heard the other day, which I don't have a cite for,
is that Labour recently cancelled a planned review/inquiry/analysis of
the holistic costs of different electrical generation scenarios.

The question is, what's the effect, practically and economically, of taking
a thermal power plant on and off line, instead of running it throughout and
varying the output a little?

Note that Drax has 6 boilers and turbines, so 'a little' is probably 17%.

This is not new - we've been using coal plants as backup reserve for several
years now.

I would guess (but I don't know) that the periods being talked about is of
the order of days/weeks, not hours. In other words, the forecast says we're
going to have a dunkelflaute next week, so crank up the boiler. It runs for
two weeks and then goes back to 'idle'.

The other question is what 'idle' means. Can you keep the boilers on
'simmer', up to temp but not producing much steam? Then you throw some more
logs on the stove ahead of when you need the steam. I don't know what the
losses of an idling thermal plant are, but surface area to volume suggests
you can retain heat in a large boiler for a long time. (such happened with
steam locomotives, on a much smaller scale)

I'd guess that all this has been thoroughly tested during the years that
coal plants were used during the winter only and, since Drax is really a
coal plant wearing a green hat, it's no different.

Theo

charles

2025-02-11 13:15:02 UTC

Post by Nick Finnigan

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

There doesn't seem anything intrinsically wrong with that.
Obviously, we want Drax when there isn't enough wind or solar, so
the profit it makes during those periods has to cover the fact it
isn't making money when wind and solar are available.
We all know that is the basic economics of having dispatchable
generation stations to cover peak periods.
The worrying thing I heard the other day, which I don't have a cite
for, is that Labour recently cancelled a planned
review/inquiry/analysis of the holistic costs of different
electrical generation scenarios.

The question is, what's the effect, practically and economically, of
taking a thermal power plant on and off line, instead of running it
throughout and varying the output a little?

Note that Drax has 6 boilers and turbines, so 'a little' is probably 17%.

This is not new - we've been using coal plants as backup reserve for
several years now.
I would guess (but I don't know) that the periods being talked about is
of the order of days/weeks, not hours. In other words, the forecast says
we're going to have a dunkelflaute next week, so crank up the boiler. It
runs for two weeks and then goes back to 'idle'.
The other question is what 'idle' means. Can you keep the boilers on
'simmer', up to temp but not producing much steam? Then you throw some
more logs on the stove ahead of when you need the steam. I don't know
what the losses of an idling thermal plant are, but surface area to
volume suggests you can retain heat in a large boiler for a long time.
(such happened with steam locomotives, on a much smaller scale)
I'd guess that all this has been thoroughly tested during the years that
coal plants were used during the winter only and, since Drax is really a
coal plant wearing a green hat, it's no different.
Theo

As a student, I 'worked' in a coal fired power station in 1959. I seem to
remeber it took 4 days to get a set up to temperature. It's only hydro
power that has an ON/OFF switch.

--
from KT24 in Surrey, England - sent from my RISC OS 4té²
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

Pancho

2025-02-11 14:25:55 UTC

Post by Nick Finnigan

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

There doesn't seem anything intrinsically wrong with that.
Obviously, we want Drax when there isn't enough wind or solar, so
the profit it makes during those periods has to cover the fact it
isn't making money when wind and solar are available.
We all know that is the basic economics of having dispatchable
generation stations to cover peak periods.
The worrying thing I heard the other day, which I don't have a cite
for, is that Labour recently cancelled a planned
review/inquiry/analysis of the holistic costs of different
electrical generation scenarios.

The question is, what's the effect, practically and economically, of
taking a thermal power plant on and off line, instead of running it
throughout and varying the output a little?

Note that Drax has 6 boilers and turbines, so 'a little' is probably 17%.

This is not new - we've been using coal plants as backup reserve for
several years now.
I would guess (but I don't know) that the periods being talked about is
of the order of days/weeks, not hours. In other words, the forecast says
we're going to have a dunkelflaute next week, so crank up the boiler. It
runs for two weeks and then goes back to 'idle'.
The other question is what 'idle' means. Can you keep the boilers on
'simmer', up to temp but not producing much steam? Then you throw some
more logs on the stove ahead of when you need the steam. I don't know
what the losses of an idling thermal plant are, but surface area to
volume suggests you can retain heat in a large boiler for a long time.
(such happened with steam locomotives, on a much smaller scale)
I'd guess that all this has been thoroughly tested during the years that
coal plants were used during the winter only and, since Drax is really a
coal plant wearing a green hat, it's no different.
Theo

As a student, I 'worked' in a coal fired power station in 1959. I seem to
remeber it took 4 days to get a set up to temperature. It's only hydro
power that has an ON/OFF switch.

Not contradicting what you say in anyway, but they turn Drax down every
night. (3GW in the day, 1GW over night). So clearly there is an ability
to idle(ish), in a 24 hour cycle. i.e. Turning output up and down is
probably distinct for changing temperature.

Adrian

2025-02-11 13:58:59 UTC

Post by Theo
The other question is what 'idle' means. Can you keep the boilers on
'simmer', up to temp but not producing much steam? Then you throw some more
logs on the stove ahead of when you need the steam. I don't know what the
losses of an idling thermal plant are, but surface area to volume suggests
you can retain heat in a large boiler for a long time. (such happened with
steam locomotives, on a much smaller scale)

The other issue is what does this do to the boiler. Keeping the boiler
at working temperature means that it is subject to certain constant
stresses, warming it up and cooling it down on a regular (FSVO) basis is
quite likely to be a bad thing for it, meaning that the maintenance load
on it increases in the long run. It could be that the payment structure
covers that adequately.

Adrian
--
To Reply :
replace "diy" with "news" and reverse the domain

If you are reading this from a web interface eg DIY Banter,
DIY Forum or Google Groups, please be aware this is NOT a forum, and
you are merely using a web portal to a USENET group. Many people block
posters coming from web portals due to perceieved SPAM or inaneness.
For a better method of access, please see:

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Theo

2025-02-11 18:01:21 UTC

I'm assuming they're not swinging the boiler temperature very much. When
it's 'idling' it's at say 98C, when it's producing steam it's at 100C. The
more wood they throw at it the more steam them make, but it stays at 100C
(unless they run out of water). OK it's high pressure steam so probably not
100C at 1atm, but at whatever working pressure/temperature they use.

You'd only drop the temperature during the summer when you know it's not
going to be needed, or during scheduled maintenance. That would reduce the
number of cycles to a handful per year. Of course that depends on the
losses when 'idling' being low enough to keep it on tickover.

Because you aren't heating it from cold, perhaps the time to raise it from
98C to 100C wouldn't take massively long (hours not days)?

Theo

Chris Hogg

2025-02-11 19:44:39 UTC

On 11 Feb 2025 18:01:21 +0000 (GMT), Theo

I'm assuming they're not swinging the boiler temperature very much. When
it's 'idling' it's at say 98C, when it's producing steam it's at 100C. The
more wood they throw at it the more steam them make, but it stays at 100C
(unless they run out of water). OK it's high pressure steam so probably not
100C at 1atm, but at whatever working pressure/temperature they use.
You'd only drop the temperature during the summer when you know it's not
going to be needed, or during scheduled maintenance. That would reduce the
number of cycles to a handful per year. Of course that depends on the
losses when 'idling' being low enough to keep it on tickover.
Because you aren't heating it from cold, perhaps the time to raise it from
98C to 100C wouldn't take massively long (hours not days)?
Theo

Maybe I'm misunderstanding you, but I would assume that steam in all
modern fossil-fuel-burning power stations was highly superheated and
supercritical, and much hotter than just above the BP of water,
somewhere around 500 to 600°C.

A problem with rapid fluctuations in temperature, as would be the case
if Drax were running in true rapid on-off mode would be the refractory
brickwork in the vicinity of the burners in the boiler. Slow run up
and run down allows gentler and more uniform expansion and contraction
of the brickwork, putting much less stress on it, less spalling and
longer lasting.

The company I used to work for has a Proteus gas turbine for
emergencies. It only took a few minutes (about five IIRC) to go from
start to full generation, and everyone within half a mile knew about
it!

--
Chris

SteveW

2025-02-11 21:52:57 UTC

Post by Chris Hogg
On 11 Feb 2025 18:01:21 +0000 (GMT), Theo

I'm assuming they're not swinging the boiler temperature very much. When
it's 'idling' it's at say 98C, when it's producing steam it's at 100C. The
more wood they throw at it the more steam them make, but it stays at 100C
(unless they run out of water). OK it's high pressure steam so probably not
100C at 1atm, but at whatever working pressure/temperature they use.
You'd only drop the temperature during the summer when you know it's not
going to be needed, or during scheduled maintenance. That would reduce the
number of cycles to a handful per year. Of course that depends on the
losses when 'idling' being low enough to keep it on tickover.
Because you aren't heating it from cold, perhaps the time to raise it from
98C to 100C wouldn't take massively long (hours not days)?
Theo

Maybe I'm misunderstanding you, but I would assume that steam in all
modern fossil-fuel-burning power stations was highly superheated and
supercritical, and much hotter than just above the BP of water,
somewhere around 500 to 600°C.
A problem with rapid fluctuations in temperature, as would be the case
if Drax were running in true rapid on-off mode would be the refractory
brickwork in the vicinity of the burners in the boiler. Slow run up
and run down allows gentler and more uniform expansion and contraction
of the brickwork, putting much less stress on it, less spalling and
longer lasting.
The company I used to work for has a Proteus gas turbine for
emergencies. It only took a few minutes (about five IIRC) to go from
start to full generation, and everyone within half a mile knew about
it!

Brings back memories of testing a newly built 24MW, RB211 powered
generator set, at full load, with all the acoustic enclosure doors wide
open. We spent months getting ready, sorting problems, etc. and when we
finally had a successful start at about 16:30, it was decided to keep
going for the 8-hour run-test. By midnight, the local housing estate was
not at all happy, but legally we were allowed 10 noisy nights per year.

Nick Finnigan

2025-02-11 22:21:06 UTC

Post by Chris Hogg
On 11 Feb 2025 18:01:21 +0000 (GMT), Theo

I'm assuming they're not swinging the boiler temperature very much. When
it's 'idling' it's at say 98C, when it's producing steam it's at 100C. The
more wood they throw at it the more steam them make, but it stays at 100C
(unless they run out of water). OK it's high pressure steam so probably not
100C at 1atm, but at whatever working pressure/temperature they use.
You'd only drop the temperature during the summer when you know it's not
going to be needed, or during scheduled maintenance. That would reduce the
number of cycles to a handful per year. Of course that depends on the
losses when 'idling' being low enough to keep it on tickover.
Because you aren't heating it from cold, perhaps the time to raise it from
98C to 100C wouldn't take massively long (hours not days)?
Theo

Maybe I'm misunderstanding you, but I would assume that steam in all
modern fossil-fuel-burning power stations was highly superheated and
supercritical, and much hotter than just above the BP of water,
somewhere around 500 to 600°C.
A problem with rapid fluctuations in temperature, as would be the case
if Drax were running in true rapid on-off mode would be the refractory
brickwork in the vicinity of the burners in the boiler. Slow run up
and run down allows gentler and more uniform expansion and contraction
of the brickwork, putting much less stress on it, less spalling and
longer lasting.

It seems they keep them on simmer, with the turbines still turning
https://www.drax.com/uk/power-generation/the-night-shift/

Chris J Dixon

2025-02-12 08:52:31 UTC

1 - (T-cold)/(T-hot)
All measured in K. The T-cold is going to be as close to 100C (373K) as they
can manage, the temperature of the steam as it exits the low-pressure turbine.
T-hot is the steam temp as it enters the high-pressure turbine. So you can get
close to 60%.
Then you shove the steam into a cooling tower.

Well, you extract the heat from the steam in the condenser, a
vast structure beneath the low-pressure turbine, which warms
water in a secondary circuit, which in turn is cooled in the
towers.

During my thin sandwich degree course, I spent time at Eggborough
power station. All that generation of power stations with 500 MW
alternators had suffered from delays and faults requiring
significant repair work - things were about 5 years late at the
time. The previous designs had been 120 MW, and a number of
aspects hadn't scaled well, resulting in premature and
catastrophic failures.

One of my tasks involved taking the shipping rubber bands off
a cabinet of relays, which were already well outside their
stamped 5-year warranty date. I was intrigued by one relay whose
function was, as condenser vacuum fell, to open the turbine hall
roof vents, so that the anticipated blast (1) didn't take all the
windows out.

(1) The low pressure turbine casings included a special explosion
vent comprising a thin metal sheet normally sucked onto a mesh
frame, with a sharp spike poised above it. If pressure becomes
positive, the metal bulges and is pierced by the spike to vent to
atmosphere

Chris

--
Chris J Dixon Nottingham UK
***@cdixon.me.uk @ChrisJDixon1

Plant amazing Acers.

Spike

2025-02-12 09:33:42 UTC

Post by Chris Hogg
Maybe I'm misunderstanding you, but I would assume that steam in all
modern fossil-fuel-burning power stations was highly superheated and
supercritical, and much hotter than just above the BP of water,
somewhere around 500 to 600°C.

Another critical thing is to avoid water droplets in the steam, as they
damage the turbine blades, so that’s another reason for T-hot being so
high.

--
Spike

Chris Green

2025-02-12 10:09:50 UTC

Another critical thing is to avoid water droplets in the steam, as they
damage the turbine blades, so that’s another reason for T-hot being so
high.

Yes, I remember back in the 1960s on a school 'industrial tour' we
visited one of the main turbine generator manufacturers and they
showed us blades that had been perforated by water droplets.

--
Chris Green
·

me9

2025-02-14 01:38:29 UTC

Yes, I remember back in the 1960s on a school 'industrial tour' we visited
one of the main turbine generator manufacturers and they showed us blades
that had been perforated by water droplets.

That's why tehy use superheaters and reheaters, dry steam is essential.

--
braind

Pancho

2025-02-12 11:20:51 UTC

Another critical thing is to avoid water droplets in the steam, as they
damage the turbine blades, so that’s another reason for T-hot being so
high.

Not really. T-hot is high for Carnot efficiency, as Tim says. That isn't
the worry for water droplets. The worry is that you want T-cold as low
as possible. So they condense the steam with cooling. In my own layman
understanding, condensation of steam creates low pressure (1 psia) which
helps the flow through the turbines. The problem occurs in the final
turbine nearest to the cold exhaust.

me9

2025-02-14 01:37:07 UTC

1 - (T-cold)/(T-hot)
All measured in K. The T-cold is going to be as close to 100C (373K) as
they can manage, the temperature of the steam as it exits the low-pressure
turbine. T-hot is the steam temp as it enters the high-pressure turbine.
So you can get close to 60%.
Then you shove the steam into a cooling tower.

Nearly right. T-hot is the temperature at which the boiler metalwork won't
yield, T-min is teh temperature in the condenser. which is as close (or
lower) than ambient as can be obtained. the condenser is cooled by sea water
or river water, which is additionally cooled by evaporative cooling in the
towers. I remeber when ferrybridge B (After C was in use) had its cooling
towers removed (to reduce maintenance costs, the loss of cooling by just
using river water was only a couple of percent, only in summer months with
low river flow. As by then it was only used for peak winter demand it was
insignificant.

--
braind

me9

2025-02-14 01:27:30 UTC

Post by Theo
I'm assuming they're not swinging the boiler temperature very much. When
it's 'idling' it's at say 98C, when it's producing steam it's at 100C.
The more wood they throw at it the more steam them make, but it stays at
100C (unless they run out of water). OK it's high pressure steam so
probably not 100C at 1atm, but at whatever working pressure/temperature
they use.
You'd only drop the temperature during the summer when you know it's not
going to be needed, or during scheduled maintenance. That would reduce
the number of cycles to a handful per year. Of course that depends on the
losses when 'idling' being low enough to keep it on tickover.
Because you aren't heating it from cold, perhaps the time to raise it from
98C to 100C wouldn't take massively long (hours not days)?

The boilers run at nearly teh critical point for water, several hundred degC
for best efficiency.

The generation of turbines of the vintage of Drax (660Mw) were built for a
very small number of cold starts. they were generally used as base load (as
nuclear are when they are working). For quick load changes they were
sometimes run as rolling reserves (synced to mains but exitation reduced to
give next to zero output). If turned off other than for major maintenance
they were kept warm with steam.

--
braind

The Natural Philosopher

2025-02-12 15:07:50 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

There doesn't seem anything intrinsically wrong with that.
Obviously, we want Drax when there isn't enough wind or solar, so the
profit it makes during those periods has to cover the fact it isn't
making money when wind and solar are available.
We all know that is the basic economics of having dispatchable
generation stations to cover peak periods.
The worrying thing I heard the other day, which I don't have a cite
for, is that Labour recently cancelled a planned
review/inquiry/analysis of the holistic costs of different electrical
generation scenarios.

The question is, what's the effect, practically and economically, of
taking a thermal power plant on and off line, instead of running it
throughout and varying the output a little?

Note that Drax has 6 boilers and turbines, so 'a little' is probably 17%.

You can modulate coal/wood boilers down but it isn't particularly
efficient. Drax like nuclear is run as baseload
Gas is the one that bears the brunt of the whores drawers effect of
renewables. But efficiency suffer massively. Until a CCGT is fully hot
with the steam plant going its efficiency is less than 40%. And it needs
about ten minutes to get to that.

--
Any fool can believe in principles - and most of them do!

Nick Finnigan

2025-02-12 22:52:34 UTC

Post by The Natural Philosopher
You can modulate coal/wood boilers down but it isn't particularly
efficient. Drax like nuclear is run as baseload

What does Gridwatch show for Biomass overnight?

The Natural Philosopher

2025-02-13 04:14:53 UTC

Post by The Natural Philosopher
You can modulate coal/wood boilers down but it isn't particularly
efficient. Drax like nuclear is run as baseload

What does Gridwatch show for Biomass overnight?

It runs flat out mostly, looks like power is reduced at around midnight
- 3 a m on some boilers

--
"Anyone who believes that the laws of physics are mere social
conventions is invited to try transgressing those conventions from the
windows of my apartment. (I live on the twenty-first floor.) "

Alan Sokal

Andrew

2025-02-11 12:33:25 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

There doesn't seem anything intrinsically wrong with that.
Obviously, we want Drax when there isn't enough wind or solar, so the
profit it makes during those periods has to cover the fact it isn't
making money when wind and solar are available.
We all know that is the basic economics of having dispatchable
generation stations to cover peak periods.
The worrying thing I heard the other day, which I don't have a cite
for, is that Labour recently cancelled a planned
review/inquiry/analysis of the holistic costs of different electrical
generation scenarios.

The question is, what's the effect, practically and economically, of
taking a thermal power plant on and off line, instead of running it
throughout and varying the output a little?

Well it will probably constrain the nice juicy dividends that
Drax have been paying me for a few years.

The Natural Philosopher

2025-02-12 14:42:33 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

There doesn't seem anything intrinsically wrong with that.
Obviously, we want Drax when there isn't enough wind or solar, so the
profit it makes during those periods has to cover the fact it isn't
making money when wind and solar are available.
We all know that is the basic economics of having dispatchable
generation stations to cover peak periods.
The worrying thing I heard the other day, which I don't have a cite
for, is that Labour recently cancelled a planned
review/inquiry/analysis of the holistic costs of different electrical
generation scenarios.

The question is, what's the effect, practically and economically, of
taking a thermal power plant on and off line, instead of running it
throughout and varying the output a little?

Massive. Someone who did a consultancy for Eirgrid was told it took
20,000 euros of gas to get a CCGT up to speed before it was running at
any kind of efficiency

--
It’s easier to fool people than to convince them that they have been fooled.
Mark Twain

Spike

2025-02-10 13:30:46 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

”Dr Doug Parr, Greenpeace's policy director, said. "We have cheap, clean
power sources available…”

And where in the scheme of things are these ”cheap, clean power sources”?

I can’t see the effect of them on my energy bills.

--
Spike

Chris Hogg

2025-02-10 15:58:13 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

Dr Doug Parr, Greenpeace's policy director, said. "We have cheap, clean
power sources available
And where in the scheme of things are these cheap, clean power sources?
I cant see the effect of them on my energy bills.

I note he omitted the word 'reliable'...

--
Chris

brian

2025-02-11 07:58:55 UTC

Post by Chris Hogg

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

”Dr Doug Parr, Greenpeace's policy director, said. "We have cheap, clean
power sources available…”
And where in the scheme of things are these ”cheap, clean power sources”?
I can’t see the effect of them on my energy bills.

I note he omitted the word 'reliable'...

Cheap, clean, reliable - pick two.

I had a colleague at work, who believed in something he called "an
existence theory". If something was possible, it would have been done
already. We are where we are , How's the cold fusion doing ?

Brian

--
Brian Howie

Joe

2025-02-11 16:31:22 UTC

On Tue, 11 Feb 2025 07:58:55 +0000

Post by brian

Post by Chris Hogg

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

”Dr Doug Parr, Greenpeace's policy director, said. "We have cheap,
clean power sources available…”
And where in the scheme of things are these ”cheap, clean power sources”?
I can’t see the effect of them on my energy bills.

I note he omitted the word 'reliable'...

Cheap, clean, reliable - pick two.

Where government is involved, *one* would be a considerable achievement.

And 'cheap' won't be the one.

Post by brian
I had a colleague at work, who believed in something he called "an
existence theory". If something was possible, it would have been done
already.

There's certainly some truth in that, but I'd add further conditions of
'reliable and economic' for it to be done outside a laboratory. We saw
laboratory models of wave and tidal power many decades ago, and while
there are a few real-world implementations, they obviously have not yet
been made genuinely reliable and economic. Scientists often do not
realise what a hostile environment the great outdoors actually is,
particularly on coastlines.

But when a new idea is touted as 'cheap' or 'will reduce household
bills', you know absolutely certainly that if that were true, it would
already be in use, nobody would be waiting for the government to
subsidise it and there would not possibly be any reason to require it
by law.

--
Joe

Jim the Geordie

2025-02-10 16:41:27 UTC

Post by Andy Burns
<https://www.bbc.co.uk/news/articles/cwyplj7dkw2o>

I don't think that's possible/practical as it takes a long time to
restart a thermal (coal, gas, biomass) power station. Pumped storage and
nuclear don't have that problem as I recall.

--
Jim the Geordie

mm0fmf

2025-02-11 09:16:37 UTC

Post by Jim the Geordie
nuclear don't have that problem as I recall.

You can't just start and stop U235 reactors. A major fission decay
product is Xe135 which is a massive neutron absorber. As you increase
the neutron flux you get more fission and more Xe135 which absorbs a
neutron to become Xe136. It poisons the reactor and you have to wait
till the fission decay and neutron absorption rates are balanced. Going
from 0 to 100% power can take 50-70 hours. The amount of poisoning is a
function of the power level the reactor ran at and the change in power.
Big changes in power having greater poisoning.

You can see the effect by watching the EDF nuclear status page. When
reactors get restarted you can see the power level being ramped up over
a day or so.

It's one of the reasons they run reactors at full tilt all the time.

Nick Finnigan

2025-02-11 09:51:00 UTC

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

Some of them didn't and don't.

https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf

mm0fmf

2025-02-11 10:57:09 UTC

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

Some of them didn't and don't.
https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf

Cheers for that. It does refer to modern designs and I am doubting that
applies to the UK's AGR fleet which will be mid-60s early 70s designs.

Looking at the gridwatch data the UK nuclear fleet appears to run at
what looks to be continuous output.

SteveW

2025-02-11 22:03:22 UTC

Post by mm0fmf

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

Some of them didn't and don't.
https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-
following-e.pdf

Cheers for that. It does refer to modern designs and I am doubting that
applies to the UK's AGR fleet which will be mid-60s early 70s designs.
Looking at the gridwatch data the UK nuclear fleet appears to run at
what looks to be continuous output.

Which is ideal - lots of nukes, constant power, make it cheap when
demand is low, so people heat stored water, charge EVs, heat their homes
then and even out the peaks. Any excess at these times can be used to
produce Hydrogen for later use for transport, etc.

Andy Burns

2025-02-12 21:21:50 UTC

Post by mm0fmf
Looking at the gridwatch data the UK nuclear fleet appears to run at
what looks to be continuous output.

Which is ideal - lots of nukes, constant power, make it cheap when
demand is low

I was watching an interview with a chap (probably a nobody) who is
proposing that Germany could recommission some of their nukes for under
€1bn each

He also says the early German PWRs could ramp-up/down at about 12% of
capacity per minute, and be run as "peaker" plants

<https://en.wikipedia.org/wiki/Neckarwestheim_Nuclear_Power_Plant>

The Natural Philosopher

2025-02-13 04:11:34 UTC

Post by mm0fmf
Looking at the gridwatch data the UK nuclear fleet appears to run at
what looks to be continuous output.

Which is ideal - lots of nukes, constant power, make it cheap when
demand is low

I was watching an interview with a chap (probably a nobody) who is
proposing that Germany could recommission some of their nukes for under
€1bn each
http://youtu.be/UWMPBfQZFsk

Probably worth doing

Post by Andy Burns
He also says the early German PWRs could ramp-up/down at about 12% of
capacity per minute, and be run as "peaker" plants
<https://en.wikipedia.org/wiki/Neckarwestheim_Nuclear_Power_Plant>

All reactors can be run below max, but the nuclear reactions are
difficult to manage if not designed for it

--
You can get much farther with a kind word and a gun than you can with a
kind word alone.

Al Capone

The Natural Philosopher

2025-02-12 15:11:52 UTC

Post by mm0fmf

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

Some of them didn't and don't.
https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf

Cheers for that. It does refer to modern designs and I am doubting that
applies to the UK's AGR fleet which will be mid-60s early 70s designs.
Looking at the gridwatch data the UK nuclear fleet appears to run at
what looks to be continuous output.

That is because it makes no sense to tirn them down,. The cost saved is
minimal and the income lost is a fact of life anyway. Nuclear is always
the cheapest bidder on the market.

--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.

The Natural Philosopher

2025-02-12 15:10:28 UTC

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

Some of them didn't and don't.
https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf

France runs freshly fuelled reactors in load following until Xenon
poisoning makes it tricky

The Natrium reactor is a far better idea. The working fluid is molten
salt and they hold a huge store of it, so the heatbank can be tapped at
various power levels to allow modulation above and below the reactor
output.

--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.

Nick Finnigan

2025-02-12 22:55:56 UTC

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

Some of them didn't and don't.
https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf

France runs freshly fuelled reactors in load following until Xenon
poisoning makes it tricky

When does that happen ?

The Natural Philosopher

2025-02-13 04:07:45 UTC

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

Some of them didn't and don't.
https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf

France runs freshly fuelled reactors in load following until Xenon
poisoning makes it tricky

When does that happen ?

When does what happen?

--
You can get much farther with a kind word and a gun than you can with a
kind word alone.

Al Capone

Nick Finnigan

2025-02-13 09:27:14 UTC

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

Some of them didn't and don't.
https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf

France runs freshly fuelled reactors in load following until Xenon
poisoning makes it tricky

When does that happen ?

When does what happen?

'Xenon poisoning makes it tricky' to run 'reactors in load following'.

The Natural Philosopher

2025-02-13 10:34:41 UTC

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

Some of them didn't and don't.
https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf

France runs freshly fuelled reactors in load following until Xenon
poisoning makes it tricky

When does that happen ?

When does what happen?

'Xenon poisoning makes it tricky' to run 'reactors in load following'.

http://www.templar.co.uk/downloads/0203_Pouret_Nuttall.pdf

That's where I got the info from

And elsewhere, but I cant remember the source.

--
You can get much farther with a kind word and a gun than you can with a
kind word alone.

Al Capone

Nick Finnigan

2025-02-13 10:52:04 UTC

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

Some of them didn't and don't.
https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf

France runs freshly fuelled reactors in load following until Xenon
poisoning makes it tricky

When does that happen ?

When does what happen?

'Xenon poisoning makes it tricky' to run 'reactors in load following'.

http://www.templar.co.uk/downloads/0203_Pouret_Nuttall.pdf
That's where I got the info from
And elsewhere, but I cant remember the source.

Yes, that mentions Xenon poisoning, extra control rods, transients when
moving the control rods, but nothing about 'freshly fuelled' or 'until'.

The Natural Philosopher

2025-02-13 11:36:23 UTC

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

Some of them didn't and don't.
https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf

France runs freshly fuelled reactors in load following until Xenon
poisoning makes it tricky

When does that happen ?

When does what happen?

'Xenon poisoning makes it tricky' to run 'reactors in load following'.

http://www.templar.co.uk/downloads/0203_Pouret_Nuttall.pdf
That's where I got the info from
And elsewhere, but I cant remember the source.

Yes, that mentions Xenon poisoning, extra control rods, transients
when moving the control rods, but nothing about 'freshly fuelled' or
'until'.

Yup. It might have been something by Kathryn Porter TBH

--
In a Time of Universal Deceit, Telling the Truth Is a Revolutionary Act.

- George Orwell

The Natural Philosopher

2025-02-13 11:54:06 UTC

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

Some of them didn't and don't.
https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf

France runs freshly fuelled reactors in load following until
Xenon poisoning makes it tricky

When does that happen ?

When does what happen?

'Xenon poisoning makes it tricky' to run 'reactors in load following'.

http://www.templar.co.uk/downloads/0203_Pouret_Nuttall.pdf
That's where I got the info from
And elsewhere, but I cant remember the source.

Yes, that mentions Xenon poisoning, extra control rods, transients
when moving the control rods, but nothing about 'freshly fuelled' or
'until'.

Yup. It might have been something by Kathryn Porter TBH

This is more detailed-
"Refuelling of fuel in the nuclear reactor is periodically performed for
each fuel cycle. After each refuelling, the nuclear fuel needs to be
conditioned. The conditioning of nuclear fuel limits the periods when
load following is suitable. Therefore, the first period after a
refuelling, only baseload operation should be performed. In addition,
calibration of equipment is done during the conditioning. The
conditioning typically takes around 7-14 days. Also, close to the end of
the fuel cycle, flexible operation should be avoided due to a reduction
in reactivity margins in the core and the conditioning of the existing
fuel. This period can be up to a month or even longer. [4] It is also
important to avoid load following when a fuel failure have been
detected. This is due to previous experiences where even small
temperature changes may lead to secondary damages of the fuel rods."

https://lup.lub.lu.se/luur/download?func=downloadFile&recordOId=9020022&fileOId=9020046

I cant hold all the detail in my head, so I absorb the salient facts
only and rely on detailed research to fill in the gaps.

1 Fundamentally the nuclear reactions change throughout the fuel cycles
and load following is only advisable at certain periods of the fuel cycle.

2 Load following is completely *possible*.

3 Load following is very uneconomic. The marginal cost of the fuel used
to run the reactor is so low that nothing is saved by turning it down or
off and it may well suffer increased wear.

So it can be done, but mostly if possible you dont.

--
You can get much farther with a kind word and a gun than you can with a
kind word alone.

Al Capone

Andy Burns

2025-02-13 16:54:58 UTC

2 Load following is completely possible.
3 Load following is very uneconomic. The marginal cost of the fuel used
to run the reactor is so low that nothing is saved by turning it down or
off and it may well suffer increased wear.

The reason it was done in Germany was that the plants had been given a
limit of TWh, which they hoped could be extended if they waited for a
change of government, so they wanted to keep them running, but then
Merkel and Fukushima happened.

charles

2025-02-13 17:45:01 UTC

#
and Tsunami occur in inland Germany

--
from KT24 in Surrey, England - sent from my RISC OS 4té²
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

The Natural Philosopher

2025-02-13 17:52:39 UTC

#
and Tsunami occur in inland Germany

Greens. The wankers choice since 1970

--
“A leader is best When people barely know he exists. Of a good leader,
who talks little,When his work is done, his aim fulfilled,They will say,
“We did this ourselves.”

― Lao Tzu, Tao Te Ching

Andrew

2025-02-14 12:03:34 UTC

#
and Tsunami occur in inland Germany

Well they did have some pretty catastrophic flooding after
freak, biblical rain not too long ago.

Like Hinckley suffered about 400 years ago.

Chris Hogg

2025-02-14 12:23:41 UTC

#
and Tsunami occur in inland Germany

Well they did have some pretty catastrophic flooding after
freak, biblical rain not too long ago.
Like Hinckley suffered about 400 years ago.

AIUI, the cause of which has never been established with certainty.
https://en.wikipedia.org/wiki/1607_Bristol_Channel_floods

--
Chris

The Natural Philosopher

2025-02-13 17:52:06 UTC

2 Load following is completely possible.
3 Load following is very uneconomic. The marginal cost of the fuel
used to run the reactor is so low that nothing is saved by turning it
down or off and it may well suffer increased wear.

And they sued the government and won.

me9

2025-02-14 01:45:04 UTC

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

If you look at the frenc hversion of gridwatch, the french often modulate
their nuclear ouput down overnight, but only about the amount that we
produce, about a tenth of their's. A problem of being mostly nuclear.

--
braind

mm0fmf

2025-02-14 10:02:52 UTC

Post by me9

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

I failed to add I was talking about the UK reactors which do seem to run
at almost constant load.

The Natural Philosopher

2025-02-14 11:16:27 UTC

Post by mm0fmf

Post by me9

Post by mm0fmf
It's one of the reasons they run reactors at full tilt all the time.

I failed to add I was talking about the UK reactors which do seem to run
at almost constant load.

That's overwhelmingly for economic, not technical, reasons.

--
“I know that most men, including those at ease with problems of the
greatest complexity, can seldom accept even the simplest and most
obvious truth if it be such as would oblige them to admit the falsity of
conclusions which they have delighted in explaining to colleagues, which
they have proudly taught to others, and which they have woven, thread by
thread, into the fabric of their lives.”

― Leo Tolstoy

The Natural Philosopher

2025-02-10 21:36:20 UTC