Energy From Thorium Discussion Forum

It is currently Jun 23, 2018 10:33 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 39 posts ]  Go to page Previous  1, 2, 3  Next
Author Message
 Post subject: Re: UK AGRs
PostPosted: Feb 18, 2014 7:45 pm 
Offline

Joined: Oct 28, 2013 12:24 am
Posts: 258
Great reactivity accidents leading to rapid core meltdown or accidents involving damages to the RPV are maybe postulated for the EPR.


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Feb 18, 2014 7:51 pm 
Offline

Joined: Apr 19, 2008 1:06 am
Posts: 2230
The old workhorse AGR may have its points after all. While the new designs are being fine-tuned, the AGR can be tried for thorium-plutonium fuel. At the very least, it will convert plutonium worryingly in stock to U-233 in used fuel. U-233 can be extracted and used as fissile fuel after a simpler chloride volatility from used fuel, if and when required for LFTR or any other fast or thermal breeder reactor.


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Feb 22, 2014 11:25 am 
Offline

Joined: Jul 20, 2010 12:52 pm
Posts: 187
Quote:
But thats just because EPR is a disaster.


Is that because it is over-designed (double containment, etc.) or other reasons? Why is the price so absurdly high? Do you know? It's going to be interesting to see the costs of the EPR's now being completed at Taishan. My bet is that they will still beat out Olkiluoto in getting it running despited starting construction 4 years later.


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Feb 22, 2014 11:30 am 
Offline

Joined: Jul 20, 2010 12:52 pm
Posts: 187
Quote:
One reason EPR is costly is that first of a kind problems are not yet over.


The reactor at Taishan will be completed this year, and that is a long time before they will break ground in the UK. OK, it isn't actually done yet, but you would think the level of experience at this point would have allowed a lower price than is quoted in the UK. So, FOAK is not the reason. That leaves an increased regulatory burden and possibly that no one in the UK remembers how to pour concrete ... that is a shorthand for a lack of recent experience in large infrastructure projects. But, even that doesn't seem likely ... so it leaves regulatory.


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Feb 22, 2014 11:32 am 
Offline

Joined: Jul 20, 2010 12:52 pm
Posts: 187
Sorry, should have read to the end of the thread. Appreciate all the comments on EPR design.


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Feb 22, 2014 12:06 pm 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1521
SteveK9 wrote:
Quote:
But thats just because EPR is a disaster.


Is that because it is over-designed (double containment, etc.) or other reasons? Why is the price so absurdly high? Do you know? It's going to be interesting to see the costs of the EPR's now being completed at Taishan. My bet is that they will still beat out Olkiluoto in getting it running despited starting construction 4 years later.


EPR is just a Gen II PWR that achieves increased safety by throwing more safety grade electrical and mechanical equipment at the problem.
Just look at the Concrete and Steel inputs compared to the AP1000 or the ESBWR.


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Feb 22, 2014 12:46 pm 
Offline

Joined: Jul 14, 2008 3:12 pm
Posts: 5053
The concrete and steel input isn't a factor in the high cost of Olkiluoto EPR. We're talking millions worth of concrete and steel, not billions that were in the cost overruns. It's a lot more complicated and mysterious than anyone has been able to explain it to me. Reactor equipment itself appears to be on budget, largely. Quality control in the civil works and electrical equipment is a major factor, but even then its weird. Even if you have 3 blokes standing about how the fourth bloke or gal is doing a simple job, you still can't get to these crazy cost overruns. And the many construction/spec errors are also strange, if you have 3 blokes breathing down the neck of the fourth, how the hell can you make that many construction errors???

It is still a big mystery to me. I suspect somewhere along the line a lot of people are raking in return on investment at crimal return rates, and are getting away with it. They are raking in billions, literally, on this project, and no one seems to be bothered because everyone is too busy slamming nuclear power for its high cost.

Technology is only a minor factor I think. AP1000s use a lot less material and are simpler than EPRs, but they are 10x + the cost of earlier PWRs that used a lot more concrete and steel and were more complicated, even when taking into account inflation.


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Feb 23, 2014 8:00 pm 
Offline

Joined: Apr 19, 2008 1:06 am
Posts: 2230
The AGR's are being operated by the EdF who are also building the EPR and yet are seriously considering extending their life. The matter may not go as far as building more of AGR but Th-Pu could be tried out as a better MOX. The French or EdF use a lot of MOX and could try out the thorium version.


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Feb 24, 2014 3:56 am 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1521
Until privatisation a very large fraction of AGR fuel was derived from re-enriched Magnox Depleted Uranium.

But those days are long gone.


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Feb 27, 2014 4:41 am 
Offline

Joined: Apr 19, 2008 1:06 am
Posts: 2230
The owners of plutonium should lease one for trials of Th-Pu fuel.
They could try out CERMET, ceramic PuO2 with metallic thorium.
Once the long burn up and fuel economy are proved, they could offer fuel for the PWR and fast reactors working at that time.


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Nov 07, 2014 1:37 pm 
Offline

Joined: Oct 28, 2013 12:24 am
Posts: 258
To return on the subject of the EPR core catcher. I talked a little with a man which works in EDF (the main french operator). He said to me that EDF and AREVA (the designer of the EPR) have studied (and are still studying) In-Vessel-Retention in case of a core meltdown. He said that for the moment they don't have a sufficient level of knowledge to convince the ASN (the french regulator) that in vessel retention is a reliable method, so they are still working on it (for using it for actual PWRs and the EPR). They have too big issues :

  • In case of a rapid core meltdown, the thermomechanical constraints are so high that they can not garantee for now that the vessel will resist.
  • If the vessel fails they have to deal with possible steam explosions. Another issue for the regulator.

That's why they choose, several years ago, to use a dry core catcher for the EPR.


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Nov 08, 2014 1:17 am 
Offline

Joined: Apr 19, 2008 1:06 am
Posts: 2230
Huge 1650 MW PWR reactor vessel is by itself a big bomb if it fails. They should possibly use a lower pressure primary coolant/moderator like biphenyl/diphenyl oxide used as a stimulant coolant for Berkeley AHTR.


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Nov 08, 2014 8:14 am 
Offline

Joined: Oct 28, 2013 12:24 am
Posts: 258
Quote:
They should possibly use a lower pressure primary coolant/moderator like biphenyl/diphenyl oxide used as a stimulant coolant for Berkeley AHTR.


It seems that diphenyl oxide is flammable and explosive. And you still have to deal with some pressure since it boils at 258°C. I am not sure that it will be stable under neutron flux.

It melts at 27°C so I guess that you can't refuel and inspect the reactor like current PWRs with mens in the containment. There is 14C formation also.


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Nov 08, 2014 9:34 am 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3631
Location: Alabama
Dowtherm is for simulating the fluid behavior of reactor fluids, NOT for use in a reactor!


Top
 Profile  
 
 Post subject: Re: UK AGRs
PostPosted: Nov 08, 2014 11:12 am 
Offline

Joined: Apr 19, 2008 1:06 am
Posts: 2230
I guess that for a less volatile coolant, we may have to stick to salts or metals. Some fluorinated hydro carbons, with or without an oxygen atom or two may work. We tolerate carbon in a graphite moderator, so C-14 may be a minor nuisance. I had earlier studied hexafluoro propyl ether polymer, an engine lubricant.
If dowtherm works when the reactor is running and stands neutron strikes, it could be promoted from simulant to the real thing. Carbon compounds can be found from solids to liquids and gases. We could find or synthesize a suitable one.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 39 posts ]  Go to page Previous  1, 2, 3  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group