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 Post subject: Re: Areva's EPR troubles
PostPosted: Apr 26, 2015 7:00 pm 
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The operators elf are considering extending the life of the AGRs. The idea may get across to those deciding the design of future power plants. Some carbide may also be found to have a longer life as moderator. Th-Pu fuel will have a longer burn up. All gradual evolution.


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jun 29, 2015 5:57 pm 
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http://af.reuters.com/article/commoditi ... 3420150624
An indication of problems to earliest starters with EPR. It may be time to look for a more economic solution.


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jun 30, 2015 8:42 pm 
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An indication of problems to earliest starters with EPR. It may be time to look for a more economic solution.


Has work totally stopped on these reactors? The article said they were TEN years overdue! I really don't understand. This is not new technology. In this day and age, the facility should have been fully computer modeled prior to the first shovelful of earth being dug.

The older plants seemed to have less problems being built. The drawings were hand drawn. They only had plastic models to check things out with. I've read that the problem was a controls system issue. This doesn't make sense. There are less moving parts on a nuke plant than on a coal plant and the distributed control systems on the coal plants work just fine.

As the interest charges for the money to be paid back mounts up, it will get to the point where the benefits of this plant will never be able to pay back the bankers.


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jul 01, 2015 6:16 pm 
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Quote:
Has work totally stopped on these reactors


The construction work is mainly done, what remain is essentially the commissioning phase with all the tests and the final documents for the safety autority and the operator. The commissioning phase will normally begin in 2016.

Quote:
The article said they were TEN years overdue!

The 9 years delay is mainly due to the completely unrealistic schedule at the contract signature : 4 years for the delivery of this first of a kind reactor while the first of a kind of the previous serie ( which was less innovative and complicated ) took 12 years.
There was also a period where they was very low progress because the safety autority didn't validate the control system of the power plant.
And there was also some errors made during the construction. Building a nuclear reactor is not easy, the construction of the first AP1000 in China is also several years late.

Quote:
This is not new technology.


No, every new design brings new technologies which must be validated by the safety autorities. For the EPR, there are the new control systems, the new general architecture, the core catcher, etc.

Quote:
In this day and age, the facility should have been fully computer modeled prior to the first shovelful of earth being dug.


The contract was signed very rapidly, the final design was not completed at that time.

Quote:
There are less moving parts on a nuke plant than on a coal plant and the distributed control systems on the coal plants work just fine.


If we compare the construction of a coal plant to the construction of a first-of-a-kind generation 3 nuclear reactor in western Europe ...

Quote:
As the interest charges for the money to be paid back mounts up, it will get to the point where the benefits of this plant will never be able to pay back the bankers.


It is mainly AREVA which must pay the cost overruns not the operator.


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jul 03, 2015 3:14 am 
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A few hundred reactor pressure vessels for LWR have been built over the last 50 years in a dozen countries. Building one takes from a few years to more than a decade. Reminds one of pyramids of Egypt which are an interesting archaeological wonder but are not built any longer as mausoleums.
Canadians had the right idea when they put in a few hundred pressure tubes in each reactor. You could build a thousand or two and hold them in stock for building new reactors or for re-tubing the old ones. I guess that the material of the tubes, unlike the pressure vessels, could be recycled. You cold also have the same or different fluids in the low pressure drum and the high pressure tubes.
An interesting variation would be low pressure molten salt in the drum and water moderator and/or coolant in the tubes. Beats Zirconium Hydride of Transatomic design.


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jul 04, 2015 11:12 am 
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[url]An interesting variation would be low pressure molten salt in the drum and water moderator and/or coolant in the tubes. Beats Zirconium Hydride of Transatomic design.[/url]

Yes - I think if one of these small pressure vessels were to ever "rock up" with hardened salt, it would be easier to heat it to thaw the salt. Water would take advantage of the many many years of dealing with the Rankine cycle.

Would you allow the water to boil or would it be a three looper with pressurized water? A three looper may allow easier maintenance on the turbine being a PWR.

[url]A few hundred reactor pressure vessels for LWR have been built over the last 50 years in a dozen countries.[/url]

Again - Despite the variations by Areva, it seems as though past experience should have allowed the EPR to be built by now. Even is there was some re-engineering, it would have been for smaller components (or software) and a capable organization would have handled it.


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jul 05, 2015 8:14 am 
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Quote:
A few hundred reactor pressure vessels for LWR have been built over the last 50 years in a dozen countries. Building one takes from a few years to more than a decade. Reminds one of pyramids of Egypt which are an interesting archaeological wonder but are not built any longer as mausoleums.
Canadians had the right idea ...


The construction time of the CANDUs is the same than for LWRs built in the same period. For the pressure vessels, hundreds of them have been forged it is not a big problem.

Concerning the vessel of the Flamanville EPR it seems that it is in accordance with the old regulation ( RCC-M regulation which is comparable with ASME ), it is not in accordance with the new french regulation ESPN. The vessel was forged in years 2005-2006 when it was still legal to use the RCC-M regulation, so I guess that the vessel will be accepted after some work with the safety autority. It is just that EDF wanted to be in accordance with the new regulation but the vessel itself is not weaker than previous vessels, it is the regulation which is more stringent.

@Eino
Quote:
it would have been for smaller components (or software) and a capable organization would have handled it.


The control system of the EPR works but, unlike the control system of a coal power plant, it must perform the safety functions and is therefore submitted to extreme requiriments. It is just that the finnish safety autority took a lot of time to validate it. Yes there were also mistakes made during the construction but is not like if the other companies don't have problems.

Well I read the thread once again and I don't understand your agressivity against Areva but whatever, do as you want, I am tired of this.


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jul 05, 2015 9:35 pm 
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Well I read the thread once again and I don't understand your agressivity against Areva but whatever, do as you want, I am tired of this.


I guess I've been accused of many things in my time, but never of "agressivity". I have no thoughts one way or another regarding that company, I've just been trying to understand what the barriers to the completion of these plants has been. My intent has not been to offend. I've worked at operating nuke plants and those under construction in the US so I'd guess European QA can be a formidable challenge to completion. fab - You are under no obligation to respond. I thank you for your previous response.


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jul 06, 2015 4:16 pm 
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Well excuse me Eino, I have gone too far, it is true that there was a lot of problems at Olkiluoto, but I don't know if I would have been better than them. Maybe I tend to be kind with the nuclear firms because I like nuclear and everybody is attacking us. I see everybody ( journalists, politicians, public on general forums, ...) insulting Areva and EDF all the time, I am tired of it. The last story with the vessel of Flamanville where the public say that Areva can no longer make PWR's vessel, whereas in reality the vessel is surely stronger than the previous ones, achieves me.

For me I am just a student, I am in internship and I also didn't understand the problems with the Olkiluoto's EPR. I tried to get some informations but it is very difficult if we are not in the construction teams.

For the people interested that's the story that I understand :
The part of Areva which is responsible of the reactors is Areva NP ( Areva NP is just a part of Areva ). The ancestor of Areva NP ( before the formation of the cluster Areva) is Framatome ANP.

The previous french nuclear power plants was co-designed by EDF and Framatome ANP ( the technology was purchased at Westinghouse and then modified ). EDF was the main constructor and Framatome was only responsible of the nuclear components ( mainly the primary circuit ) and the control system.

The last series of french nuclear power plant is the "N4 series". The first N4 took 12 years to be on grid but it was not a big problem at that time, it seems that they forecasted it, there was no big cost overrun. With nearly 80 % of electricity coming from PWRs there was no longer a need for new power plants and so there was a long period with no construction and a great loss of experience.

In case of future possible construction EDF had a concept which was derived from the N4, the REP 2000 ( REP means PWR ).
But the french responsibles at that time decided to form Areva and make an alliance with Siemens for the design of the EPR which
must satisfied both french and german standards and safety autorities. EDF was associated to the project but I heard that they didn't appreciate this processus and the design of the EPR, they felt to be "left apart", some people say that EDF didn't want the EPR.

And then there was a war between the leaders of Areva and EDF. And for the Olkiluoto plant EDF was not associated : Areva had to be the main constructor of this reactor alone ( never happened before, Framatome was just responsible of the design and nuclear component ) and build it in 4 years whereas the final design was still not achieved and that the first N4 took 12 years.
And then there was a lot of misunderstanding between Areva, the operator and the safety autority which didn't help,for example with the control system validation.

For now I heard that the Olkiluoto EPR plant is roughly at the same level than the Taishan 1 EPR, but Taishan will be on grid first, normally in 2016 because of the will of the chinese operator to be the fastest possible and the commisioning phase which is easier in China I guess.

It seems that EDF will take control of Areva NP. Now EDF and Areva are co-designing their new model of reactor, the EPR NM ( NM for New Model and this is not Atmea), which is more simple than the current EPR.

edit : Well happy birthday Eino, I just saw it. :D


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jul 07, 2015 12:48 am 
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it is really a time for next generation of reactors. Of the present gen of PWRs, VVER is the most successful but carries the Russian stigma of RBMK. Some breeder or MSR or better still, an MSR breeder is required now. Graphite breeder is marred by a short life.
Therefore even the MSR should either be moderated by water or be an unmoderated one.


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jul 13, 2015 2:29 am 
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http://www.bbc.com/news/science-environment-33469774

Any thoughts as to whether EDF will press ahead with Hinckley?

If they don't, then no one else will go ahead with a EPR - which is pretty much the end of Areva (unless they can quickly dust down the designs for Karena). Given that, I don't think the French Government will allow EDF to back out - but the decision is taking a long time. Maybe EDF are asking for a higher payment, but £90/MWh is already overly generous.


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jul 13, 2015 6:00 pm 
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For the vessel here what I understood : the first measures tend to show that the vessel complies with the previous regulations and it was made during a transition period when it was possible legally to use the old regulation. The seggregation of carbon in the bottom of the vessel is a known phenomenon and it is not a problem for the safety of the vessel : the area where there is a surplus of carbon is away from the welds, away from the neutron flux, and it is more in compression during a cold thermal shock, so there is not an increased risk of brittle fracture. There will be future tests and work with the safety autority for the qualification of the vessel.

For Areva : the most probable scenario is that EDF will take control of Areva NP (the reactor part of Areva).


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jul 13, 2015 7:10 pm 
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A major problem with the EPR I think is it is basically a Gen II PWR that gets its extra safety by throwing more systems and generators and stuff at the problem. This means regulatory ratcheting has really badly hurt it. Whereas we see with the AP1000, the ESBWR and even to a lesser extent the ABWR to introduce passive safety systems in place of the active ones.
The savings from that has partially offset the explosion in costs.


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jul 14, 2015 10:41 am 
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I think that what we mostly need is to build several reactors of the same design in order to regain the experience and have less regulatory work. The reactors built in Taishan benefited of the experience gained on the Olkiluoto and Flamanville and the construction is faster partly because of that (although there are some differences between each different EPR because of local requirements).

About the complexity : yes, if I was a designer ( I am not ) with total freedom, I would also prefer to try simplify everything at the maximum and use simplified passive systems each time it is possible if they are reliable (passive systems can also fail).

Some safety authorities won't allow you to simplify everything, they will also ask for active systems in order to have a diversity of technology and because they are more proven and that we have more experience with them. Or they will simply refuse your safety system until you can convince them that it will work. For example : why there is no in-vessel-retention of the molten core in the EPR, like the AP1000 ? The people said me that the french safety authority simply does not accept it for now, so they could not use it. And it is the same thing with a lot of systems.

The new model of EPR (the EPR NM) will be more simple than the current EPRs for what I heard.


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 Post subject: Re: Areva's EPR troubles
PostPosted: Jul 14, 2015 1:30 pm 
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Absolutely, getting multiple reactors going is vital to the economics. So we just have to find some way to swallow the higher initial costs of this approach, as first units will cost more. This appears feasible in some countries, but other countries have such entrenched business and regulatory regimes it seems difficult to change now. Many people in the industry now have their job because of the bureaucratic environment.

As to the EPR... for sure the added complexity risks this design getting into the typical nuclear build pitfalls, and it looks like the regulator and/or plant owner at Olkiluoto doesn't accept any deviations from the design due to insights gained during construction. That means that regulator and/or plant owner is totally clueless as to the realities of large construction projects. Large projects are NEVER built to exact paper design but most deviations are harmless, so there is a need for an effective management of change policy (risk-based) on this, not denial and delusion that all real world construction details and arising issues can be solved in a computer before the first shovel hits the ground...

The core catcher I'm not so sure about. This EPR is a massively large reactor, thermal rating wise I mean. Based on the AP1000 analysis I've seen, it works, but there are not huge margins to some of the critical thermal limits, especially considering the uncertainties in heat fluxes, core relocation events, etc. Its a very difficult multiphysics problem.

I know that the ESBWR design team actively rejected the invessel retention strategy (except for small core damage events) because of structural support considerations combined with workability in the lower area (the melt retention ability of the lower vessel head must be assured by supporting the equipment in a specific way, that relieves the vessel head from stress, which is very difficult if you have to work there for control rod drive replacement and such).

In the case of the EPR in the US design I think it was, the design team made a change to have the core catcher be actively activated rather than the thermal fuse valve. This was due to a regulator (I think NRC) question. It is a very odd choice, since the primary reason for needing the core catcher is that most of your active power equipment is unavailable, like a long term SBO with batteries depleted. So that valve would not longer work when its needed the most. Sounds like a typical Fukushima thing to me. LWR designs don't adequately consider common mode failures, in my opinion.


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