AC (funny they're always anonymous, isn't it....)
You can find the necessary details in the UK GDA documentation for both types. The EPR follows existing French practice in that it uses what are called "grey control rods" to permit the fine controls that's needs to offset Xenon poisoning effects. The AP1000 uses fine control drives on its conventional rods for similar effect.
If you'd thought for a moment, you'd realise that in the various nations where 50% or above of electricity production MUST have their nuclear plants at least in part in load-following mode, or have very much flatter daily demand profiles than we do. Take France as the most obvious example - their daily swing isn't disimilar to ours (2:1 rather that the 2 1/2:1 we see). There simply isn't the non-nuclear capacity on the system to accomodate that variation.
" Any backup needed by wind power because the wind is allegedly unpredictable is to a large extent also needed by inflexible nuclear "
Not if you do the numbers.
National Grid has recommend that the spinning reserve equal to the average output of any connected wind capacity must be kept connected - as wind variations equal to that within a three hour threshold have been observed on the system on multiple occasions. Spare capacity equal to 90-95% of total connected wind capacity is required for longer outages.
(National Grid - "Operating the Transmission System in 2020")
At the moment, we maintain spinning or other rapid response reserve equal to the largest credible unit loss - 1200MW for Sizewell (or part of the French interconnector). That'll go to 1600MW when we have EPRs on the grid.
Following Grid's advice would (at the current average wind capacity factor of 27% - from last year's RO annual report), would mean that once connected wind capacity goes above about 5GW - roughly where it is now - extra spinning reserve PURELY TO ACCOMODATE WIND VARIATION. If we were to see 20% of production from wind, against an average demand of 40GW, we'd see spinning reserve increasing roughly eight-fold.
And no, it's not primarily or even exclusively to accomodate nuclear - it's just as much defined by the probablity of losing a large coal-fired or gas-fired unit.
"How are the EPRs at Olkiluotuo and Flamanville doing? "
About that badly. But, as you'd expect with a series build, the third and fourth units (at Taishan) are pretty much on time and budget . What's remarkable is just how consistent this is with earlier French experience of introducing new designs.
Wh9ich, in large measure goes to show what made a big controbution to the screw-ups in the earlier UK programmes.
I can't think of many large novel developments that don't show the same sort of behaviour - think A380 and B787, for example.
What is more remarkably, perhaps is that the AP1000 lead sites are running bang-on time and budget (at Sanmen and Haiyang). The difference is, Westinghouse learned from Japanese experience and modularised the plant. The first pressure vessel went into Sanmen-1 on the 23rd September - within about a week of plan.
"Who will be paying for the cost overrruns at Olkiluoto and Flamanville?"
Areva. They;ve just announced provisions in their annual results.
"Citation needed - isn't "about to build" putting it a bit strong wrt any plans for UK nuclear capacity?"
Not really. The EPR has to all intents and purposes completed GDA, and awaits only the site clearances for Hinkley Point and Sizewell. In fact, you'll find anti-nuclear groups are complaining that EdF has broken ground for site preparations at Hinkley.
As to the Germans, Volker Beckers couldn't have been stronger in an interview just a week ago:
(Updates with closing RWE share price in 11th paragraph.)
Oct. 4 (Bloomberg) -- RWE AG and EON AG are pressing ahead with plans to build new reactors in the U.K. after the German government ordered the closure of nuclear plants at home.
“We are still recruiting people and spending almost a million pounds ($1.54 million) every single week,” Volker Beckers, chief executive officer of RWE's U.K. Npower division, said in an interview in Bloomberg's London bureau.
“In Germany, a big proportion is against nuclear power stations, while here you see an increase in acceptance. For an investor it's key you invest into a country where you have a supportive framework: political, commercial and social. I do see this in the U.K.”
“We need to sustain 12 gigawatts of nuclear. We need investments in renewables, we need gas plant as part of the mix and we need a certain slice of coal plant so we can manage volatility in commodity prices.”
I found that 12GW number interesting. Assuming he's talking for RWE as a whole, if Germany does go through with it's nuclear retirement plans, that's suggesting RWE building another 9 GW (over and above it's 50% of Horizon's 6GW).
(If you want to search it, the interview was with "Business Week", dated 4/10/11).
Horizon's due to make its technology choice in December. My money's on the AP1000.
What's most intriguing at the moment was this, from Mike Weightman earlier in the week
http://www.reuters.com/article/2011/10/12/us-britain-nuclear-idUSTRE79B1QT20111012
He's committing to provide a team to complete the ESBWR GDA - but only in a timescale that's consistent with the NuGeneration consortium's timescales. That suggests to me that GE-Hitachi has good reason to think that its got a very good chance of winning the NuGeneration deal. It's also telling that the declared size for their Sellafield project is consistent with building a pair of ESBWRs.