Thorium plans in Norway
Giuseppe
driven system,rather than a critical nuclear reactor,what do you know about?
I couldn't find any technical details...
http://www.reuters.com/article/environmentNews/idUSL3045358520070330
Alex Terrell
We had a brief discussion on this some time ago.
The thread has some links which might still be up to date.
It is an accelerator system which is sub critical, and can also be
used to transmutate nasty waste stuff.
Mishagam
2000 MW, guess it is impossible now.
Also you loose most of protection given by zirconium rods and reactor
vessel in current reactors.
Generally, I don't think this will be ever done. I think only realistic
way to use Thorium is in thorium breeder reactors, starting with
Plutonium or Uranium 235 and converting Thorium to Uranium 233.
Giuseppe
"Mishagam" <noe...@provider.com> ha scritto nel messaggio
news:4628e956$0$4870$4c36...@roadrunner.com...
According to this paper they haven't still decided which kind of reactors to
build
http://www.statkraft.no/Images/Bergfald_tcm3-6904.pdf
I think there are at last only two choices (in thermal spectrum) to use
thorium as a fuel: high temperature "pebble bed" reactors devepoped in
'70/'80 and dedicated heavy water reactors like those developed in
India.Both reactors need a (very high) "start" of fissile uranium or
plutonium and very unlikely can be breeders,i.e. conversio ratios higher
than 1,at last "near breeder" systems (CR higher than 0,8-0,9) rather than
breeder
Mishagam
usual nuclear reactor (and requires for similar power all the
construction elements of usual nuclear reactor), but you have to add
very costly and consuming a LOT of energy and not developed yet (for
needed power) cyclotron to each reactor, and you also use some of
reactor protections to allow stream of protons into reactor.
I don't think this will ever work.
brushhead
Nuclear engineer, though, i'm Electronics, but interested in Atomic tech.
Cheers,
Rob.
Giuseppe
"brushhead" <chai...@mfi.com> ha scritto nel messaggio
news:46290fe8$0$8714$ed26...@ptn-nntp-reader02.plus.net...
Russia,China,India and Japan are all highly investing in *fast* breeder
(sodium cooled) reactor,i.e. uranium/plutonium cycle based fuel plants
Thorium,instead,can be used in current nuclear technology with slow
neutrons,so can be easily developed in short time,although is not really
"breeder" technology,rather an "high converter" one - it can produce from
thorium 232 as much 90/95 % uranium 233 fissile from a begining fissile
fuel,pratically only plutonium or higly enriched uranium
http://www.world-nuclear-news.org/explorationNuclearFuel/200407-US_and_Russi
an_companies_make_thorium_fuel_alliance.shtml
http://www.world-nuclear-news.org/newNuclear/180407-Mitsubishi_to_develop_Ja
pan_s_next_fast_breeder_reactor.shtml
>
> Cheers,
>
> Rob.
dez...@usa.net
Subcritical systems are just too damned expensive to be worthwhile.
Try again in 30 years when we have plasma wake accelerators that can
give us spallation on the cheap maybe, but I wont hold my breath.
Today the best way to use thorium is to mix it in instead of the U238
in CANDU systems, then in light water reactors. The best prospect for
a breeding reactor that utilizes thorium is probably a liquid fluoride
thorium reactor.
Mishagam
rods and so have full radioactivity fluid circulating around reactor. So
you again lose two primary barriers for radioactivity - zirconium rods
and reactor vessel. How you will prevent leaks of radioactive elements,
especially if there are some problems? In usual reactor you just have to
keep water in reactor, and this works in most cases.
Because of this problem I doubt that fluoride reactor will ever work.
Mishagam
Also France had several big fast breeder reactors, Phoenix and Super
Phoenix but they all are probably closed now.
Giuseppe
"Mishagam" <noe...@provider.com> ha scritto nel messaggio
news:46292ab9$0$16675$4c36...@roadrunner.com...
> Giuseppe wrote:
> > "brushhead" <chai...@mfi.com> ha scritto nel messaggio
> > news:46290fe8$0$8714$ed26...@ptn-nntp-reader02.plus.net...
> >> Giuseppe wrote:
>
> >>>
> >> I thought that breeders were a dead duck? Or am I out of date. I'm
not
> >> Nuclear engineer, though, i'm Electronics, but interested in Atomic
tech.
> >
> > Russia,China,India and Japan are all highly investing in *fast* breeder
> > (sodium cooled) reactor,i.e. uranium/plutonium cycle based fuel plants
> > Thorium,instead,can be used in current nuclear technology with slow
> > neutrons,so can be easily developed in short time,although is not really
> > "breeder" technology,rather an "high converter" one - it can produce
from
> > thorium 232 as much 90/95 % uranium 233 fissile from a begining fissile
> > fuel,pratically only plutonium or higly enriched uranium
>
> Also France had several big fast breeder reactors, Phoenix and Super
> Phoenix but they all are probably closed now.
Only Phenix (about 250 MWe) is still working,but it was converted from
"breeder" to "burner" of plutonium and transuranics.In year 2004 produced
about 700 milions of kWh
http://world-nuclear.org/wgs/decom/database/php/qry_reactorsdb_details_test.
php?var1=France&var2=Phenix&var3=FBR&var4=FBR&var5=Operating&var6=Commissari
at a l'Energie Atomique (CEA)&var7=233&var8=MWe_Net&var9=Avignon&var10=01
November 1968&var11=Expected by 2
Giuseppe
As far I know no molten salts reactor is never built,except some research
ones in a very small scale...I'm very sceptical about this
technology,altough seems very promising on paper.The best ways to burn
thorium remains in the mid term heavy water reactors and high temperature
(htr) reactors like those "pebble beds" that South Africans are developing
and building.Two prototype of thorium htr plants were built in Us and
Germany (about 300 MWe each) in the '70,but unfortunately with no exiciting
and definitive results
dez...@usa.net
> deza...@usa.net wrote:
> > On Apr 20, 2:05 am, "Giuseppe" <g...@tiscali.it> wrote:
> >> What kind of thorium plant is it?It seems me something like an accelerator
> >> driven system,rather than a critical nuclear reactor,what do you know about?
> >> I couldn't find any technical details...http://www.reuters.com/article/environmentNews/idUSL3045358520070330
>
> > Subcritical systems are just too damned expensive to be worthwhile.
> > Try again in 30 years when we have plasma wake accelerators that can
> > give us spallation on the cheap maybe, but I wont hold my breath.
>
> > Today the best way to use thorium is to mix it in instead of the U238
> > in CANDU systems, then in light water reactors. The best prospect for
> > a breeding reactor that utilizes thorium is probably a liquid fluoride
> > thorium reactor.
>
> >http://thoriumenergy.blogspot.com/
>
> But as I understand liquid fluoride reactors, they have no zirconium
> rods and so have full radioactivity fluid circulating around reactor. So
> you again lose two primary barriers for radioactivity - zirconium rods
> and reactor vessel. How you will prevent leaks of radioactive elements,
The reactor vessel itself, the containment dome. Your loop is hot, but
this isn't a showstopper.
> especially if there are some problems? In usual reactor you just have to
Leaks are self sealing, as the salts solidify outside of the reactor
and lock the fission products up in them.
> keep water in reactor, and this works in most cases.
Why would you use water?
> Because of this problem I doubt that fluoride reactor will ever work.- Hide quoted text -
Its just a different model. It has benfits of being much more
passively safe than other reactor designs. Overheating of the reactor
leads to melting of a freeze plug and draining into dump tanks. Much
simpler fuel cycle, no fuel fabrication, enrichment, 1/100th the waste
stream, better neutron economy. lower fissile load. Much lower
pressures.
Mishagam
> On Apr 20, 1:34 pm, Mishagam <noem...@provider.com> wrote:
>> But as I understand liquid fluoride reactors, they have no zirconium
>> rods and so have full radioactivity fluid circulating around reactor. So
>> you again lose two primary barriers for radioactivity - zirconium rods
>> and reactor vessel. How you will prevent leaks of radioactive elements,
>
> The reactor vessel itself, the containment dome. Your loop is hot, but
> this isn't a showstopper.
>
>> especially if there are some problems? In usual reactor you just have to
>
> Leaks are self sealing, as the salts solidify outside of the reactor
> and lock the fission products up in them.
So reactor vessel will have radioactivity that in LWR is found only
inside zirconium rods.
>
>> keep water in reactor, and this works in most cases.
>
> Why would you use water?
In LWR zirconium rods with uranium fuel are always under water. Water
serves many functions, including keeping rods cool and intact. In
Three-Mile Island incident rods melted only after water boiled away.
>
>> Because of this problem I doubt that fluoride reactor will ever work.- Hide quoted text -
>
> Its just a different model. It has benfits of being much more
> passively safe than other reactor designs. Overheating of the reactor
> leads to melting of a freeze plug and draining into dump tanks.
With the result much like after Three Mile Island accident, with melted
products of nuclear reactions inside reactor building, without even
thick steel reactor vessel.
Much
> simpler fuel cycle, no fuel fabrication, enrichment, 1/100th the waste
> stream, better neutron economy. lower fissile load. Much lower
> pressures.
>
I may be agree, but these things cannot compensate decreased safety and
removing most important barriers for radioactive contamination.
dez...@usa.net
> deza...@usa.net wrote:
> > On Apr 20, 1:34 pm, Mishagam <noem...@provider.com> wrote:
> >> But as I understand liquid fluoride reactors, they have no zirconium
> >> rods and so have full radioactivity fluid circulating around reactor. So
> >> you again lose two primary barriers for radioactivity - zirconium rods
> >> and reactor vessel. How you will prevent leaks of radioactive elements,
>
> > The reactor vessel itself, the containment dome. Your loop is hot, but
> > this isn't a showstopper.
>
> >> especially if there are some problems? In usual reactor you just have to
>
> > Leaks are self sealing, as the salts solidify outside of the reactor
> > and lock the fission products up in them.
>
> So reactor vessel will have radioactivity that in LWR is found only
> inside zirconium rods.
>
> >> keep water in reactor, and this works in most cases.
>
> > Why would you use water?
>
> In LWR zirconium rods with uranium fuel are always under water. Water
> serves many functions, including keeping rods cool and intact. In
> Three-Mile Island incident rods melted only after water boiled away.
And also serves as a moderator, that can (and have) lead to steam
explosions. Molten salts with their low vapor pressures are good for
heat transfer.
> >> Because of this problem I doubt that fluoride reactor will ever work.- Hide quoted text -
>
> > Its just a different model. It has benfits of being much more
> > passively safe than other reactor designs. Overheating of the reactor
> > leads to melting of a freeze plug and draining into dump tanks.
>
> With the result much like after Three Mile Island accident, with melted
> products of nuclear reactions inside reactor building, without even
> thick steel reactor vessel.
No, its a medium designed to be piped back into the reactor vessel.
Such an incident wouldnt scrap the reactor for good.
> Much> simpler fuel cycle, no fuel fabrication, enrichment, 1/100th the waste
> > stream, better neutron economy. lower fissile load. Much lower
> > pressures.
>
> I may be agree, but these things cannot compensate decreased safety and
> removing most important barriers for radioactive contamination.
I disagree. Just wrapping an extra pressure vessel around the core
serves the same purpose. Fluid fuel reactors are inherantly safer than
many solid fuel reactor designs (low vapor pressure). The issue isn't
reduced safety, but increased maintenance cost from the hot loop.
nada
But isn't a lot of the savings based on online fuel reprocessing
locally at the reactor?
David
Giuseppe
<dez...@usa.net> ha scritto nel messaggio
news:1177159460.5...@e65g2000hsc.googlegroups.com...
> On Apr 20, 7:22 pm, Mishagam <noem...@provider.com> wrote:
> > > Why would you use water?
> >
> > In LWR zirconium rods with uranium fuel are always under water. Water
> > serves many functions, including keeping rods cool and intact. In
> > Three-Mile Island incident rods melted only after water boiled away.
>
> And also serves as a moderator, that can (and have) lead to steam
> explosions. Molten salts with their low vapor pressures are good for
> heat transfer.
By the way,what are the problems/drawbacks of using a lead-bismuth eutectic
alloy as coolant in fast (eventually breeder) reactors,instead of very
reactive and problematic liquid sodium?
Mishagam
http://nucleartimes.jrc.nl/Doc/ICONE13-50397.pdf
Basically, sodium is lighter and so more capable to remove heat. It also
apparently less activated by neutrons. There are other points as well.
dez...@usa.net
> Giuseppe wrote:
> > <deza...@usa.net> ha scritto nel messaggio
>
> - Show quoted text -
Lead-bismuth is also corrosive.