Energy From Thorium Discussion Forum

It is currently Jun 22, 2018 3:44 pm

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 42 posts ]  Go to page Previous  1, 2, 3
Author Message
 Post subject: Re: Nuclear Education
PostPosted: Nov 02, 2013 4:19 pm 
Offline

Joined: May 05, 2010 1:14 am
Posts: 129
'It is interesting that something I have almost zero belief in (harm from climate change) is the strongest argument I have for advancing the use of nuclear. '
Climate change and nuclear power are inextricably linked, but most of the 'greenies' don't trust the solution, and a lot of the 'nukes' can't see the problem. They both need eduficating.


Top
 Profile  
 
 Post subject: Re: Nuclear Education
PostPosted: Nov 02, 2013 4:57 pm 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1521
Cyril R wrote:
Reactor grade plutonium is only good to make fizzle bombs. But spent MOx plutonium can be made into fizzle bombs without about the same level of difficulty.

U-Pu MOx is ready today... sure, it's ready to ruin reasonably good quality startup fuel for future LFTRs, right now.

Even the French admit that stopping MOx helps a future thorium reactor transition.



I am not convinced of how 'good' reactor grade plutonium actually is for LFTR start up.
Is it worth the cost of reprocessing the fuel by itself? Since we have already established that passive dry storage of the spent LWR fuel is probably comparable in cost to the storage of the high level waste from the reprocessing process.

With the price of uranium capped I think HEU probably wins out in terms of a startup fuel for a future thorium reactor, if one ever materialises.
The existing plutonium stockpile costs £80m a year to keep secure. If we are going to be waiting decades it could concievably be cheaper to burn down the current stockpile, buy some natural uranium as a hedge against price rises and then enrich it as required for the thorium programme.


Top
 Profile  
 
 Post subject: Re: Nuclear Education
PostPosted: Nov 02, 2013 6:15 pm 
Offline

Joined: Jul 14, 2008 3:12 pm
Posts: 5053
E Ireland wrote:
Cyril R wrote:
Reactor grade plutonium is only good to make fizzle bombs. But spent MOx plutonium can be made into fizzle bombs without about the same level of difficulty.

U-Pu MOx is ready today... sure, it's ready to ruin reasonably good quality startup fuel for future LFTRs, right now.

Even the French admit that stopping MOx helps a future thorium reactor transition.



I am not convinced of how 'good' reactor grade plutonium actually is for LFTR start up.


RGPu is better than 20% LEU, technically.

If RGPu isn't good for starting LFTR, it is CERTAINLY utter rubbish for starting MOx cores, as it is more expensive across the board.

RGPu is pretty good fuel for a Th converter, as it avoids the processing difficulties with plutonium in a thorium cycle, yet can get very high burnup with none of the fuel heterogeneity (local power, power coefficients) and fuel fabrication/contamination issues of MOx.

Quote:
With the price of uranium capped I think HEU probably wins out in terms of a startup fuel for a future thorium reactor, if one ever materialises.


Good luck with that, let me know when any of the powe reactor enrichers are going to make HEU for you. Weapons grade material is peanuts in the battle to start up 10000 GWe of advanced reactors.

Quote:
The existing plutonium stockpile costs £80m a year to keep secure. If we are going to be waiting decades it could concievably be cheaper to burn down the current stockpile, buy some natural uranium as a hedge against price rises and then enrich it as required for the thorium programme.


Good luck with making your MOx fuel for under 80 million a year. I doubt you could do it for 800 million a year. If simply guarding it costs 80 million a year, with that cost structure and high level defence, doing anything advanced to that could easily cost billions. The cleanup cost of the Rocky Flats facility was $7 billion.

In fact, that seems to be a disease that has infected all nuclear power programs so far.


Top
 Profile  
 
 Post subject: Re: Nuclear Education
PostPosted: Nov 02, 2013 8:41 pm 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1521
I wouldn't use the power enricher's enrichment plant to make the HEU.

I would have it enriched to 5-20% at a power enrichment plant (probably the Urenco plant at Capenhurst or the George Besse II plant at Tricastin) and then throw it in the Defence Enrichment plant that the UK maintains for the manufacture of submarine fuels (or use the British time at the American plant, whichever we are doing at the time).
The plutonium is a state asset and thus I can assume the normal commercial rules don't apply tot he Plutonium substitute Uranium.

And while in a single year making MOX fuel is rather more expensive than simply storing the plutonium, you only have to make MOX fuel once.
You don't have to refabricate the same plutonium into fuel again the next year, so eventually the burning it down option becomes cheaper.


Top
 Profile  
 
 Post subject: Re: Nuclear Education
PostPosted: Nov 03, 2013 12:24 am 
Offline

Joined: Jul 28, 2008 10:44 pm
Posts: 3065
E Ireland wrote:
I wouldn't use the power enricher's enrichment plant to make the HEU.

I would have it enriched to 5-20% at a power enrichment plant (probably the Urenco plant at Capenhurst or the George Besse II plant at Tricastin) and then throw it in the Defence Enrichment plant that the UK maintains for the manufacture of submarine fuels (or use the British time at the American plant, whichever we are doing at the time).
The plutonium is a state asset and thus I can assume the normal commercial rules don't apply tot he Plutonium substitute Uranium.

And while in a single year making MOX fuel is rather more expensive than simply storing the plutonium, you only have to make MOX fuel once.
You don't have to refabricate the same plutonium into fuel again the next year, so eventually the burning it down option becomes cheaper.

We should remind folks that when you burn MOX you don't burn all the plutonium and in the process of burning MOX you create more plutonium. So as a means to rid one's self of plutonium MOX is pretty poor. Once you have burn MOX once its fuel quality goes significantly down so that folks don't try to burn it a second time.


Top
 Profile  
 
 Post subject: Re: Nuclear Education
PostPosted: Nov 03, 2013 12:58 am 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1521
Lars wrote:
We should remind folks that when you burn MOX you don't burn all the plutonium and in the process of burning MOX you create more plutonium. So as a means to rid one's self of plutonium MOX is pretty poor. Once you have burn MOX once its fuel quality goes significantly down so that folks don't try to burn it a second time.


The plutonium's existence is not the problem.
The fact that it is seperated is the problem.
Spent MOX fuel can go into the dry casks, just like UOx (albeit with a longer water cooling period beforehand).

We can then treat it just like ordinary UOx fuel, store for up to three centuries prior to reprocessing for final disposition.

I am wondering about using Lightbridge esque fuel in a reactor, albeit tuned for comparable properties to existing UOx fuel in terms of overall burnup per assembly (so lower enrichment than they propose) since after a century or so of storage you can stamp it flat (its normally star shaped) and stack it into more compact elements.

No need to mess around with solvents (be they nitric acid or molten salt/metal) since you just crush it flat in a giant press.


Top
 Profile  
 
 Post subject: Re: Nuclear Education
PostPosted: Nov 04, 2013 10:48 pm 
Offline

Joined: Jun 05, 2011 6:59 pm
Posts: 1334
Location: NoOPWA
If you want to rid ourselves of the Pu, just make PuFFF the magic fuel and burn it in a LFTR till it is gone.

_________________
DRJ : Engineer - NAVSEA : (Retired)


Top
 Profile  
 
 Post subject: Re: Nuclear Education
PostPosted: Nov 05, 2013 6:41 am 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1521
KitemanSA wrote:
If you want to rid ourselves of the Pu, just make PuFFF the magic fuel and burn it in a LFTR till it is gone.


I don't want rid of the Pu itself particularily (I don't really care about it).

I want rid of the cost of maintaining a stockpile of separated plutonium.


Top
 Profile  
 
 Post subject: Re: Nuclear Education
PostPosted: Nov 05, 2013 8:30 am 
Offline

Joined: Jul 14, 2008 3:12 pm
Posts: 5053
E Ireland wrote:
KitemanSA wrote:
If you want to rid ourselves of the Pu, just make PuFFF the magic fuel and burn it in a LFTR till it is gone.


I don't want rid of the Pu itself particularily (I don't really care about it).

I want rid of the cost of maintaining a stockpile of separated plutonium.


It's silly. 80 million a year is peanuts compared to the value of electricity generated with that Pu pile.

You're proposing a technical solution to a political problem. And a pretty piss poor technical solution if I may say so.


Top
 Profile  
 
 Post subject: Re: Nuclear Education
PostPosted: Nov 05, 2013 12:53 pm 
Offline

Joined: Jun 05, 2011 6:59 pm
Posts: 1334
Location: NoOPWA
I like the dual use of PuFFF the magic fuel, starts up LFTRs and gets rid of Pu.

_________________
DRJ : Engineer - NAVSEA : (Retired)


Top
 Profile  
 
 Post subject: Re: Nuclear Education
PostPosted: Dec 29, 2013 1:19 pm 
Offline
User avatar

Joined: Nov 14, 2013 2:34 pm
Posts: 177
Location: Here and There
I'm new to the LFTR and need a bit of "nuclear education." Is there a P&ID (flow schematic) of a typical anticipated LFTR design? One picture is sometimes worth 10,000 words and I think this could be the situation for having a few P&IDs. :P


Top
 Profile  
 
 Post subject: Re: Nuclear Education
PostPosted: Dec 30, 2013 2:51 pm 
Offline
User avatar

Joined: Oct 06, 2010 9:12 pm
Posts: 138
Location: Cleveland, OH
One example of a flow sheet can be found in the Document Repository in ORNL-4528. In this particular design, it is a 2-fluid graphite moderated reactor that heats an intermediate salt, which then runs a steam-powered turbine for electricity, I think the reference power level is 250 MW(e).


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 42 posts ]  Go to page Previous  1, 2, 3

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:  
cron
Powered by phpBB® Forum Software © phpBB Group