Energy From Thorium Discussion Forum

It is currently Apr 23, 2018 12:20 pm

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 37 posts ]  Go to page Previous  1, 2, 3  Next
Author Message
PostPosted: Jan 04, 2012 9:24 pm 
Offline

Joined: Nov 18, 2007 11:52 pm
Posts: 76
Lead is not hard to melt and flows well. If you've ever played around with it with a blow torch, it's pretty easy to see this. I'd imagine once it is started even the decay heat will keep the lead molten around the fuel rods pretty easily. The rest could be accomplished with resistive heaters. As long as it's well insulated I don't see a problem. Of course, on submarines you run into issues of having limited space and external power.

I'd go with lead over lead-bismuth. The fact that you can melt lead-bismuth more easily melted at lower temperatures is offset by the corrosion and neutronic properties.


I'd favor the design of a reactor where the lead is never really flowing through pipes, but rather is like a big tub of lead with heat exchangers immersed in it. That removes the issue of lead freezing and stopping proper cooling. If the fuel gets hot enough to melt the lead, it will melt from the center out, absorbing heat until the entire reactor is molten lead.


Top
 Profile  
 
PostPosted: Jan 05, 2012 3:45 am 
Offline

Joined: Jul 14, 2008 3:12 pm
Posts: 5061
Pool type is also what most concepts are looking at for power production.

Here's a picture of the European Lead Cooled System:

http://www.gen-4.org/Technology/systems ... FRFig2.jpg

The fuel handling is done above the reactor, in the gas space at low temperature. To do that, they attach metal poles to the fuel rods that extend out the liquid lead. That's really clever, because manipulating fuel elements in liquid lead must be tricky.


Top
 Profile  
 
PostPosted: Jan 05, 2012 5:54 am 
Offline

Joined: Apr 19, 2008 1:06 am
Posts: 2227
It appears that a silica enamel will avoid lead-tin corrosion. A fast spectrum is also useful for a transuranic burner. TRU's from used fuel could be used for fissile feed for thorium or U238 from recovered uranium/depleted uranium.
Molten nuclear fuel in pipes could be a Molten Salt Breeder Reactor core and transfer heat to the Lead-tin bath. Any suitable coolant in another set of pipes would extract it for electric power generation or chemical process heat.


Top
 Profile  
 
PostPosted: Jan 06, 2012 10:22 pm 
Offline

Joined: Dec 27, 2011 3:59 pm
Posts: 5
Does anybody know how if better lead pumps have been developed? Or can they replace them every few months?


Top
 Profile  
 
PostPosted: Jan 07, 2012 6:42 am 
Offline

Joined: Jul 14, 2008 3:12 pm
Posts: 5061
veromies wrote:
Does anybody know how if better lead pumps have been developed? Or can they replace them every few months?


Electromagnetic pumps have been developed. They last just about forever, at the cost of tripling the pumping power requirement (lead is conductive but not world class). Probably worth it considering the pumping power requirement can be reduced by large core P/D allowed by the low lethargy of lead.

Canned motor pumps would also work, these are much more efficient, but you have to add passivation protectors to the wetted ferromagnetic surfaces, such as aluminium or silicon, and use silicon carbide/tungsten carbide for the bearings/sliders etc.

I'd consider EM pumps first.


Top
 Profile  
 
PostPosted: Feb 10, 2012 8:02 pm 
Offline

Joined: Jul 20, 2010 12:52 pm
Posts: 187
Argonne Design published:

http://www.anl.gov/Media_Center/News/20 ... 120209.pdf


Top
 Profile  
 
PostPosted: Feb 11, 2012 12:45 am 
Offline

Joined: Apr 19, 2008 1:06 am
Posts: 2227
Russians have been using Lead or lead-Bismuth cooled reactors but are also going for sodium cooled ones. They would have a solution to corrosion which could be further improved. It may beat fire prone sodium.
Requirement of energy is constantly increasing, especially in the low energy economies. Burning U238 or thorium232 will be the only way to bridge the gap and these will ultimately be burnt in breeders or fast reactors. Lead or salts may be a path away from the scare of sodium fires, once the corrosion issue is tackled.
Lead could also work in high temperature thermal reactors if a different moderator is used.


Top
 Profile  
 
PostPosted: Dec 20, 2013 12:41 pm 
Offline

Joined: Sep 01, 2009 1:01 pm
Posts: 51
http://www.snetp.eu/www/snetp/images/3. ... 6-2012.pdf

100mWe fast lead reactor spearheaded by Italians and Rumanians. (Surprising--what do they know about lead fast reactors that the Russians don't know?) 400*C inlet; 480*C outlet: sufficient to replace coal burners?

First concrete predicted in 2019.


Top
 Profile  
 
PostPosted: Dec 21, 2013 1:52 am 
Offline

Joined: Jun 05, 2011 6:59 pm
Posts: 1328
Location: NoOPWA
paul wick wrote:
http://www.snetp.eu/www/snetp/images/3.%20a.alemberti%20alfred%20-%20brux%2025-6-2012.pdf

100mWe fast lead reactor spearheaded by Italians and Rumanians. (Surprising--what do they know about lead fast reactors that the Russians don't know?) 400*C inlet; 480*C outlet: sufficient to replace coal burners?

First concrete predicted in 2019.
Why would anyone want a 100 milliWatt reactor? ;)

_________________
DRJ : Engineer - NAVSEA : (Retired)


Top
 Profile  
 
PostPosted: Dec 21, 2013 5:56 am 
Offline

Joined: Jul 14, 2008 3:12 pm
Posts: 5061
paul wick wrote:
http://www.snetp.eu/www/snetp/images/3.%20a.alemberti%20alfred%20-%20brux%2025-6-2012.pdf

100mWe fast lead reactor spearheaded by Italians and Rumanians. (Surprising--what do they know about lead fast reactors that the Russians don't know?) 400*C inlet; 480*C outlet: sufficient to replace coal burners?

First concrete predicted in 2019.


The work from Ansaldo is very promising, they've clearly got a realistic design line going with ELSY/ALFRED. Realistic temperature, safety systems design, refuelling scheme, etc.

I hope they won't try to build it in Italy. All projects there get bogged down in endless public and anti nuclear outcries, usually getting cancelled in the end, even when they are technically completely sound.


Top
 Profile  
 
PostPosted: Dec 21, 2013 5:18 pm 
Offline

Joined: Feb 28, 2011 10:10 am
Posts: 353
WNN also has a news report on this, with some more details:
http://www.world-nuclear-news.org/NN-Co ... 012134.htm

Romania is indeed a better location for this ALFRED reactor than Italy, which has no and wants no nuclear power plants at all. Ansaldo also has a close working relationship with Romania, it was involved in the construction of the CANDU reactors in Romania. I think Romania can also benefit from the special EU/EIB financing arrangements for new EU members.

However, 2025 is a little late, the Russians will be first, with their SVBR-100 and BREST-300, which will come on-line in the early 2020s,

Last but not least, why is there no similar consortium that is going to develop and build a prototype (D)MSR by that date ?


Top
 Profile  
 
PostPosted: Dec 28, 2013 1:02 am 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3533
Location: Alabama
KitemanSA wrote:
Why would anyone want a 100 milliWatt reactor? ;)


I think Enrico Fermi wanted one pretty badly in December 1942... ;)


Top
 Profile  
 
PostPosted: Dec 28, 2013 4:01 pm 
Offline

Joined: Jun 05, 2011 6:59 pm
Posts: 1328
Location: NoOPWA
Kirk Sorensen wrote:
KitemanSA wrote:
Why would anyone want a 100 milliWatt reactor? ;)
I think Enrico Fermi wanted one pretty badly in December 1942... ;)
In the "anything greater than zero" vein, I'll grant you that, but even EBR-1 lit 4 lightbulbs. :D

_________________
DRJ : Engineer - NAVSEA : (Retired)


Top
 Profile  
 
PostPosted: Dec 29, 2013 2:25 am 
Offline

Joined: Nov 23, 2010 6:51 pm
Posts: 123
I have heard about many interesting possibilities (or maybe optimistic speculations) for lead-cooled reactors, including:

- The high density and low viscosity of liquid lead making natural circulation particularly efficient, possibly feasible for power levels into the hundreds of MW
- A large negative temperature coefficient making passive load following possible and eliminating any need for the use of control rods during normal operation
- A large temperature margin to coolant boiling and fuel element failure would prevent any damage to the reactor, even if there was a sudden, total loss of active heat sink at full power combined with a shutdown rod failure (provided there is a passive heat sink for 0.5% of full power)
- The possibility of factory assembly, where the factory would process spent fuel to recover uranium and plutonium, fabricate fuel elements, assemble the core (shutdown rods first obviously), install the core into the reactor vessel, fill the vessel with lead, test the reactor by withdrawing the shutdown rods, re-insert the rods and wait for the lead to solidify, then ship the whole thing on a truck, train or boat. At the destination, the electrical generation system could be hooked up, lead could be melted with electric heaters and the reactor started by removing the shutdown rods
- Possibility of high burnup (~10% of the initial 238U converted to Pu and fissioned) with a sufficiently small change in reactivity that refuelling would not be required. When decreasing reactivity eventually lowered the idle temperature too much the reactor could be shut down, allowed to cool for a few years until the lead solidifies, then shipped back to the factory for reprocessing.

So just how wildly optimistic is all this?


Top
 Profile  
 
PostPosted: Dec 29, 2013 9:53 am 
Offline

Joined: Jul 14, 2008 3:12 pm
Posts: 5061
Not too optimistic. The physics is there. Lead is a great coolant, we trade away nasty sodium activation and chemical reactivity and a positive void coefficient, for somewhat higher corrosion rates (practically translating in slightly more expensive alloys of construction), and much higher coolant weight (again translating in higher cost to make things seismically robust).

Some of the engineering/commercial stuff remains to be demonstrated. In case of factory fabrication, true enough for the smaller units, but most larger units are pool type designs that have quite large vessels.

Some time ago I've made some additions to the Wiki article.

http://en.wikipedia.org/wiki/Lead-cooled_fast_reactor

I see it needs more updating on the recent news of the ALFRED proposal.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 37 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:  
cron
Powered by phpBB® Forum Software © phpBB Group