[Klaustrophobia]

i'm gonna stop geeking out now.

I'd geek out too.  That sounds amazing.

Too right!  That sounds like pure awesome wrapped in a pretty box with a bow on top!

On a related note, just finished reading an article on Liquid Fluoride Thorium Reactors.  I've been a pretty strong advocate of liquid metal cooled fast neutron reactors, but this is the first time I'd read about liquid salt reactors in any detail.  I feel I was criminally remiss.

The LFTR was designed and tested successfully in the 1950s.  It utilizes the Thorium fuel cycle instead of the Uranium/Plutonium fuel cycle.  The byproducts are generally less radioactive for a shorter period of time.  The fuel also stays in a liquid solution so you don't have to worry about fuel rod degradation and can keep on "burning" the fuel much further than you could otherwise.  Finally, it doesn't make Plutonium, so it is inherently proliferation proof.

Why are we not using this if it was designed over 50 years ago and proved to be better in all respects than LWRs?  Because it was proliferation-proof.  Our genius ****ing government wanted more Plutonium for their nuclear arsenal, so they ****-canned the best long-term fission reactor design I've ever seen right at the infancy of the industry and cursed us with a bull**** inefficient and dangerous fuel cycle we can't get out of.  God Bless America.

While plutonium production was undoubtedly a contributing factor, it is NOT the deciding one.  That design, while certainly a good one, is not "better in all respects" than a LWR.  First and foremost is economics.  LWRs are basic and (comparatively) cheap.  U-235 is the ONLY naturally occuring fissile isotope, making uranium fuel much easier and cheaper to procure.  One of the senior design projects my year actually was analyzing thorium fuel, and it is not yet economically viable.  Many of the things you mention sound like advantages when they are plugged by proponents of the design, but in actuality are essentially non-issues.  The length of fuel burnup in a LWR is in no way affected by fuel rod degradation.  Fuel depletion is what determines the duty cycle.  They burn it until it can't sustain a critical reaction any longer.

I've not specifically looked at liquid solution fuel ideas, but I can speak generally about some pros and cons for them.  On the pro side, it could run at higher core temperatures that would corrupt the cladding in traditional solid fuel, which can increase the thermodynamic efficiency of the power plant.  On the cons side, and this is really the huge one, is that a liquid solution is an absolute containment NIGHTMARE.  The PRIMARY barrier to radioactivity release in a nuclear plant is the fuel rod itself, and a liquid solution eliminates that.  I don't even want to imagine trying to handle the waste liquid.

The proliferation aspect is highly debatable.  If you feel strongly about non-proliferation, it might be best to skip this section and agree to disagree.  In my opinion, it should be a non-issue altogether.  We already have nuclear weapons.  The actual number we have really doesn't matter at all, it's just the fact we have them.  The capability to produce more changes exactly nothing.  We have dedicated breeders for that anyway.  As for the terrorism aspect, i am 110% confident that there is no way a terrorist organization would be able to steal fuel or waste and make a bomb out of it.  Directly addressing the point of thorium being naturally proliferation resistant, that is not exactly true.  Thorium is only a fertile isotope, meaning it has to be bred into something fissile to be useful as fuel, and either plutonium or uranium still must be present in high concentrations at the beginning of cycle.  If memory serves, the thorium fuel bundle design from the aforementioned design team was in the neighborhood of 40% Pu-239 to be able to maintain criticality at beginning of cycle.  Thorium is better in non-proliferation yes, but to state it is completely proliferation-proof is false.  But again, in my opinion, it shouldn't matter.

Last point in wall-of-text post: our current fuel cycle is fundamentally NOT inefficient or dangerous.  We certainly have the capability to close the fuel cycle, it is the politics that are making it the way it is now.  With simple breeder reactors, the uranium fuel supply can be made virtually limitless (by breeding Pu-239, back to proliferation here).  We also already know how to reprocess waste.  Even as it stands now, there really isn't a problem with the fuel cycle until we run low on U-235, which will simply force us into fast U-238 or thorium reactor designs, and essentially end up the same place, just a little slower (and more cheaply).  The panic over not having anywhere to store waste is just that: panic.  The reason we are "running out of room" is because of arbitrary capacity limits set by the government/NRC, which were extremely heavily influenced by the NIMBY from hell, not what would actually be dangerous.  Hell, we don't even really NEED a repository other than just to make us feel better by having it underground.  ALL the waste from the current reactors that have been running for 30-40 years is easily stored on-site.  Some haven't even had to move it into dry cask storage yet, their spent fuel pool still has room.

I don't mean for this to be an attack on you or the reactor designs you are talking about.  Your head is in the right place and they ARE good designs, but I really like to squish misinformation on nuclear topics as soon as I see it.  My overall point for this post is:  we simply don't need those kinds of reactors (yet) at a higher cost and a revamp of the nuclear infrastructure.

[Turambar]

some stuff might happen

i'll let you guys know how it goes

[perihelion]

I'm an enthusiastic amateur, and I appreciate your insights.

I am a bit confused by your comments on fuel rod degradation, though.  My impression was that the build-up of fission products can cause the rod itself to crack and release by fuel and byproducts directly into the coolant.  Does the reaction get poisoned by fission products before integrity becomes an issue, then?

While I do see the difficulties of dealing with liquid fuel, it seems to me that the advantages ought to outweigh them.  Even assuming fuel rod degradation is a non-issue, you are still going to have to remove a huge quantity of unburned fuel because of fission product build-up which eventually poisons the reaction.  Again, I'm no expert, so I only have a couple examples to throw out there, but Xe-135 is the one I'd been warned about.  In a liquid fuel system, separation of these byproducts from the still burnable fuel would be child's play by comparison.  Some of it will gas off (collect at the top of the reactor), some will become insoluble and fall out of solution (a bit more tricksie, but not insurmountable), some would still be liquid, but could be separated chemically or through differences in density.

I had not given much thought to the fact that you'd have to kick start the reaction with something else.  That is very good point.  Nominally, you'd be using U-233 in the kernel and Th-232 in the blanket, but in order to get to get the U-233 you'd have to make it in a fast breeder reactor.  Once you get the fuel cycle started in earnest, this problem would go away, but it does present a significant hurdle.  One would think, however, that the breeder reactors we already have for production of weapons-grade isotopes could be put to this task?

As far as proliferation goes... my issue with it is mostly that it has been made an issue.  I would probably sleep a little better knowing we weren't making more weapons-grade materiel, but at the end of the day, it is the fact that "proliferation" is being used as an excuse not to reprocess our fuel or burn it in a more efficient manner that really sticks in my craw.  If it were possible to side-step the proliferation issue by saying, "Look, we've got a fuel cycle that doesn't produce anything that could be used to build a nuclear bomb," my hope is that some of the resistance to nuclear in general, and more long-term sustainable fuel cycles specifically, could be overcome.

[Scotty]

Wrote a birthday poem for a good friend.  Lost a cat.  Going to anime night in a few hours.

Woohoo life.

[StarSlayer]

My coworkers sent me this and this.  I can't quite describe it other then being "so intense"

[Retsof]

Came home and the answering machine had a message with just three seconds of static.    I think the Trancendant is coming for me.

[qazwsx]

Bored ****less at 1AM
can't sleep due to chest pains
having a great night so far ¬_¬

[General Battuta]

My coworkers sent me this and this.  I can't quite describe it other then being "so intense"

Why is he responding so...sexually?

[iamzack]

taking mum to the airport at 4am LE SIGH

[Stormkeeper]

I realised that I haven't been updating my fan-fiction thread here, despite having gone way down the road with it.

Plus, I need to interview someone new.

[StarSlayer]

My coworkers sent me this and this.  I can't quite describe it other then being "so intense"

Why is he responding so...sexually?

Haven't a clue, but when I walked into the graphics department yesterday and they're crowded around the computer and all I could hear was the guy hyperventilating and moaning I was pretty disturbed.

[Bob-san]

I realised that I haven't been updating my fan-fiction thread here, despite having gone way down the road with it.

Plus, I need to interview someone new.

Oooh! Oooh! Don't pick me! I'm boring!!

[Scotty]

I just found out that 1337% of pi is 42.

[Jeff Vader]

I just found out that 1337% of pi is 42.

[Snail]

...Oh God...Oh Dear God...

[Colonol Dekker]

I'm taking my Rachel out to Greenwich. Assuming for a second my name was Ross.

[perihelion]

I just found out that 1337% of pi is 42.

[cough]
Rounding much?

[Jeff Vader]

I just found out that 1337% of pi is 42.

[cough]
Rounding much?

Quiet, you. It's close enough.

[Nuke]

i got back from the woods. we went fishing, blew things up with fireworks, and pissed off the captain of the fvf fairweather (cross the path of a ragnarok class at full speed, in an ursa, on insane, it was like that). all in all a fun week.

[Scotty]

I just found out that 1337% of pi is 42.

[cough]
Rounding much?

It gets closer the more digits you use.