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 Post subject: Re: UK AGRs
PostPosted: Nov 08, 2014 5:27 pm 
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Regarding EPRs, it cannot be doing AREVA any good to be analyzing the design of these multi billion dollar facilities and having costs quadruple because of it. Seems like the reactor design should have been fully analyzed prior to construction. From the literature I've seen, they just don't seem to be doing anything that hasn't been done before. What are the projected completion dates of their two European projects?


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 Post subject: Re: UK AGRs
PostPosted: Nov 08, 2014 7:24 pm 
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Quote:
Regarding EPRs, it cannot be doing AREVA any good to be analyzing the design of these multi billion dollar facilities and having costs quadruple because of it. Seems like the reactor design should have been fully analyzed prior to construction. From the literature I've seen, they just don't seem to be doing anything that hasn't been done before. What are the projected completion dates of their two European projects?


The construction of the Olkiluoto EPR and the Flamanville EPR should be finished in 2016. The construction of the 2 other EPRs at Taishan was started after Olkiluoto and Flamanville but they will finish before the european projects. Taishan 1 should be completed in 2014 or 2015. The 2 chinese EPRs seem in time and on budget.

There was a lot of issues with civil engineering and regulatory authorities.The Fukushima accident also brings additional regulatory requirements.

The last french nuclear power plant was completed in 1999. The entire french fleet of PWRs was built at a cost of 96 000 000 000 € (or 120 000 000 000 US$) for 63 GWe. That brings us a mean construction cost of 1905 US$ per kWe. The Flamanville EPR will be around 6450 US$ per kWe.

I think this is because the experience in plant's construction was lost and also that the EPR is a FOAK. There are also increasing requirements from the regulatory bodies. There are maybe other reasons but my understanding of construction economy is poor.


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 Post subject: Re: UK AGRs
PostPosted: Nov 08, 2014 8:03 pm 
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Chinese Russian and Korean reactors cost less than European or US with Japanese backing. It must be manpower costs. The 'advanced' countries have priced themselves out of competition. All the construction has also moved to Asia. The French are considering reducing the nuclear share to avoid more 'Flammenvilles'.


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 Post subject: Re: UK AGRs
PostPosted: Nov 08, 2014 8:49 pm 
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The French are considering reducing the nuclear share to avoid more 'Flammenvilles'.


The reducing of nuclear power, if it happens, will be only for political reasons (except if a new catastrophic accident happens). The construction of the Flamanville EPR was decided in case of some plants have to be shut down at 40 years lifetime and also for not loosing too much experience in construction. The entire fleet is already constructed and will probably last 60 years (and maybe 80 years if there is a lot of financial difficulties at that time, which is probable with the peak oil and gas). I don't see the french consumption of electricity rising a lot these next years, mainly for economic reasons, so I guess that the share of nuclear power will be roughly constant (or will decrease a little).

So there is no need for now to construct new plants after the Flamanville project, except if we want to overcome gas and oil peak with nuclear power, but the public opinion is against it for now. I personnally favor to use nuclear now to finish rapidly with fossil fuels but with an other design than the EPR. After Fukushima we can rapidly design a PWR with an higher safety than the AP1000 with current technology, at a price of higher capital costs but with a state financed program and a 80 years design lifetime, that should not be a great problem. Having LFTR would be formidable but it still need developpement.


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 Post subject: Re: UK AGRs
PostPosted: Nov 09, 2014 7:59 am 
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The PWRs in France are still relatively young. EDF will be spending more than 50 billion Euros in the coming 10 years to upgrade the PWRs and to extend the life to 50 or 60 years, beyond the 40 years which was originally envisaged. From a cost perspective, this may be a good alternative, as the depreciation of the plants is stretched out as well, from 40 to 60 years. Noises from within EDF also point out that the EPR is not seen as a good fit for EDF, as they are considered to be too large. There appears to be a preference for the ATMEA design (1100MWe) within EDF. The question, however, is whether new PWRs will be built in France after the Flamanville EPR has been completed.

Let's hope that the current French PWRs can be succeeded by MSRs/LFTRs in twenty to thirty years time.


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 Post subject: Re: UK AGRs
PostPosted: Nov 10, 2014 7:49 pm 
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#dowtherm

There was an experimental Canadian reactor, the WR-1, that operated successfully for many years with an organic coolant. It used terphenyls. It operated at relatively low pressures and had few (no, as far as I know) issues with corrosion. Also, it operated at 425C, which was high for its time.

It actually seemed like a very worthy design. It separated the high-radiation area from the high-pressure steam. That's a good part of the basic plan for an improved reactor, right? It used a vertical CANDU arrangement, too. It might be worthwhile to think about using some similar arrangement for the intermediate coolant loops of MSRs. Oil is immisicible with both salts and steam, so heat-exchanger leaks would have more controllable consequences. Also, if the coolant gets away, it forms a slick, rather than dissolving in surface water. (Fluorides don't dissolve either, but in that case, there's a worry that the fuel salt mixes with the intermediate loop salt because of HX leaks. Fluorides are also toxic. So are beryllium compounds. I think terphenes might be less so.).

I first read about it on the CANDU FAQ, but
there's a wikipedia article at http://en.wikipedia.org/wiki/WR-1


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 Post subject: Re: UK AGRs
PostPosted: Nov 10, 2014 8:59 pm 
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rgvandewalker - Thanks for the post. Here's another link

http://media.cns-snc.ca/history/wr-1/wr-1_3.html

This is from that link:

The organic liquid, called OS-84, selected as a coolant in WR-1 is a mixture of terphenyls treated catalytically with hydrogen to produce 40 percent saturated hydrocarbons. The terphenyls are petrochemical derivatives that are readily available and are already in use as heat transfer media.

Coolant - By weight - 70% Monsanto OS84
30% Radiolytic Tars

Now - I just wonder what the flammability of the coolant was.


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 Post subject: Re: UK AGRs
PostPosted: Nov 11, 2014 10:22 am 
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Some papers which spoke about OS-84 :

http://link.springer.com/article/10.1007/BF01059375#page-1

http://fti.neep.wisc.edu/pdf/fdm863.pdf

and therphenyl : http://en.wikipedia.org/wiki/Terphenyl

At 400°C this coolant still needs to be pressurized and it is still flammable even if the flammability seems low. If you use it as primary coolant in a solid fuel reactor, fires and explosions may be issues in great accidents with very hot molten core. The containment has to be inerted, passively cooled and pressure resistant like modern BWRs.

This is very interesting but the nuclear industry has a lot of experience with water and pressure is something that modern designs can deal with, so the advantage of using less pressurized OS-84 is maybe not that great. I think that if we leave water, I personally prefer to go for a really non-volatile and non-reactive coolant, like molten salts and lead, but I understand that people are interested by OS-84. After the graphite fire at Chernobyl and the hydrogen explosions at Fukushima, using an hydrocarbon coolant seems also difficult for PR, even if OS-84 seems not very reactive.

For using it in as a secondary coolant for an MSR, it will be pressurized and will maybe make bad chemical reactions with the fuel salt in case of leaks in the heat exchangers (which becomes more probable with the differences in pressure). An advantage is its lower melting point.


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 Post subject: Re: UK AGRs
PostPosted: Nov 11, 2014 3:05 pm 
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The organic terphenyl type coolants may not be very flammable, but that is at low temperature. The flash point is actually well below 300 degrees Celsius, so you'd be operating a nuclear reactor on a flammable liquid many degrees above its flash point. Definately needs inerted containment.

They should also react with hot steam so if you have a high pressure steam on the other side and there's a leak... that means hydrogen and other explosive gasses would be generated.


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