If you thought shutting down the railways for Monday morning commute was a poor show, now we find that two of the reactors at Dungemess have been taken offline due to the rainy and windy weather too. This from the Telegraph:
A nuclear power station automatically shut down its reactors after debris blown by hurricane-strength winds fell onto its power lines and led to a loss of supply.
It could be up to a week before the two units at Dungeness B plant in Kent – one of Britain’s nine nuclear power stations – are up and running again.
But a spokeswoman for EDF Energy, which runs the site, said she hoped energy would be restored much sooner and that the public should “absolutely not” be concerned by the shut-down.
“This is an issue caused by the unusual weather, which led to a loss of power like many of the homes in the surrounding area,” Ms Fletcher said.
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“We share the discomfort of people locally.”
The plant has the capacity to produce 1040 megawatts of energy, providing power for some 1.5 million homes.
More than 200,000 homes across the country have experienced a loss of power because of what has been dubbed ‘St Jude’s’ storm.
Tallbloke's Talkshop 
Presumably that’s the power lines coming OUT, and that a gas fired power station would also be switched off if the same happened (but it’s a lot quicker to switch on again)?
‘The plant has the capacity to produce 1040 megawatts of energy, providing power for some 1.5 million homes’
But still suffered a ‘loss of supply’ – of power 😉
Michael H: No, that’s the power lines going *in*. You’d think they would go to the extra cost of buried cable and dual redundant supplies for something like that.
You can see that Dungeness B tripped off this morning at ~7am this morning in this graph . It was coal – not gas which immediately balanced the demand on the Grid.
The other interesting observation is that Wind power output fell by over a half during the storm ! I suspect this is because most wind farms in southern Britain were shut down to protect the turbines.
Wind power is the Goldilocks fuel as far as UK energy security is concerned.
First, she tried a spoonful from Papa Bear’s great big bowl. “OW!” she yelled, “TOO WINDY!”
Next, she tried a spoonful from Mama Bear’s medium-sized bowl. “Brrrrr! TOO STILL!” she complained.
Finally, Goldilocks tried a spoonful from Baby Bear’s tiny little bowl. “YUMMY!” she cried. “THIS IS JUST RIGHT!” Goldilocks ate the entire bowlful of wind.
Wind cannot displace any Fossil Power capacity until some way is found to store the energy.
This happened in Texas about 30 years ago at the STNP outside of Houston. We had a rare ice storm, which built up ice on the large power lines leaving the plant. The wind blew the lines together and tripped massive breakers which took (if I recall correctly) days to reset. In a late 1980’s ice storm, the same thing happened at a gas fired plant much closer to Houston.
Nuke plants, and I guess all power plants, shut down if they are unable to transmit their power.
Nuclear plants all shut down if there is a loss of offsite power (such as grid failure) or if the grid frequency goes outside specified limits. What else can they do if the grid is not available?
NB 1040MW is power, not energy.
Once again for those who missed it, this was a problem with the supply *to* the reactors, not *from* them.
tallbloke, I find that worrying. That means nuclear can’t be depended on as LAST resort.
The delay to return to power is almost certainly caused by xenon poisoning of the reactors following a scram shutdown. This can take several days to clear. It has been a familiar phenomenon to all reactor operators since the very early days.
If the essential power services of a nuclear station are provided solely from the internal reactor/turbine combination, in the event of a trip these supplies would be lost and there would be no control system. Hence the reliance on external supplies. Of course there are multiple on-station standby systems but the first recourse is to the grid, which has a much greater reliablity than any individual station.
Ladies and Gentlemen I worked at Dungeness ‘B’ so have some knowledge of the actual situation there.
Dungeness ‘B’ like all nuclear power stations needs to have an emergency power supply in case a reactor trips. In such a situation the reaction of course stops but for a day or so there is around
30MW of heat to be removed to prevent reactor damage, The plant DOES have backup diesel generators but current rules require grid power as well.
Any differentiation between power in and power out is artificial. There is a single set of pylons carrying power. If the link is cut then both power in and out are affected.
As for the idea that the power lines should be buried this is impractical. Not only are the costs very high (better than £ 1 million per mile 20 years ago) but the local geology makes this quite impossible at any sane cost. Dungeness is built on a shingle spit and seperated from the mainland by Denge marsh which as its name suggests is waterlogged land below sea level.
I have no doubt the lines will be repaired within a few days and this is an unsual occurence. The reason it has become an issue is the margins of the UK power system have become wafer thin. Had this occurred in the middle of a harsh winter we could be looking at rolling blackouts.
Keith
Keith, welcome, and thanks for your input of direct knowledge. You’ve raised several points about the geographical situation I was unaware of which invalidate some of what I said. Your point about wafer thin margins is well made, and heard.
But watch who is who saying what…
A little example of the lies… read it all…
http://washingtonexaminer.com/fractivists-caught-in-flood-of-colorado-lies/article/2537929
I’m sure the same is going on in the UK.
Il y a du risque?, mon dieu non, nous allons faire une fortune.
The french are not stupid, are they? but cameron and his eaton mess, well, that’s something else.
I worked at Sizewell B, which is much more modern than Dungeness B, and has much more in the way of backup power supplies. It has four grid connections (ie two grid lines) to go with the 4-way redundancy of safety systems. If it completely loses all four grid connevctions (complete loss of offsite power), then it relies on onsite power, which consists of 4 essential diesel generators, any one of which can maintain all essential functions until the grid is restored (which would normally be expected within 24hours). In the event of failure of all 4 diesel generators then there are two steam-driven turbogenerators which can provide the essential functions. Failing those, then essential cooling would be performed using a system of bleed and feed, but we are talking here of so many failures of redundant and diverse systems, that it is more likely that the earth would be destroyed by a meteor strike.
From memory, xenon poisoning peaks at about 14 hours and, without knowing the details of Dungeness reactivity control, then I would have though it possible to get back online within 24 hours if the grid is repaired promptly.
As I recall the decay chain is something like this
iodine 135 (not a neutron poison) to xenon 135 (neutron poison) half life 6 hours or so
xenon 135 to xenon 131 (not a poison) 10 hours
So given normal operating margins restart may be possible within 24 hours but
the operators would probably prefer 48
Dungeness B like Sizewell has 4 backup diesel generators and originally could
draw power from Dungeness A as well but now that options is gone following
its decommissioning
The National Grid in Kent has of course been spending most of its capital allocation connecting
wind farm developments such as that at Herne Bay so useful projects like an extra link to Dungeness have been shelved.
clivebest says: October 28, 2013 at 5:13 pm
You can see that Dungeness B tripped off this morning at ~7am this morning in this graph . It was coal – not gas which immediately balanced the demand on the Grid.
—————————-
No not quite true the balance is maintained by pumped storage with hydro/coal/gas following
http://climateandstuff.blogspot.co.uk/2013/10/the-uk-storm-of-28th-october-and.html
Pumped storage from Dinorwig will provide full output 1.7GW within12 to 15 seconds of demand ramp up of coal and gas and hydro will be significantly slower.
clivebest says:
October 28, 2013 at 5:13 pm
“France” and wind both dropped off I see. Is France considered a renewable resource? Maybe we should try and get some of that France here in the US. We might prefer France over wind.
Will,
France is a great renewable source – Good wine and food. I also recommend Italy – even better food and life goes on despite the government. Plus it’s much warmer so less heating is needed.
Life in the UK would be much better if only it could get a bit warmer. As for extreme weather – Do the Canary Islands suffer more than Britain ?