Talk:Fast breeder reactor

EGAD!! why no mention of the thorium cycle? there's no mention of it anywhere else on wikipedia ... nor could i find info on other nuclear cycles for that matter... Discussion of it would provide good insight as to how the reactor actually produces more nuclear fuel than it uses. Thanks in advance to whoever might write something on it!


 * I'm unsure of the date of this, but currently or now there is mention of teh Thorium cycle and breeding as a major object of the Indian nuclear programme. --Midgley 23:11, 21 January 2006 (UTC)

Shouldn't this be redirected to Fast Breeder Reactor? Rmhermen 01:33, Aug 21, 2003 (UTC)

It is a bit confusing saying that fast reactors use enriched fuel and then saying they've become obselete because enriched uranium is so widely available. I assume the enriched fuel is plutonium but it is not clearly spelt out.


 * Hmmm. I hope this issue has now been addressed in the new introduction. Andrewa 07:50, 28 Oct 2004 (UTC)

This article compares fast breeder reactors (FBR) reactors to another type of reactor, PWR. But it doesn't say when PWR stands for, nor does it link to an explanatory article.


 * Fixed. Andrewa 07:50, 28 Oct 2004 (UTC)

Removed text:&#256;

''One problem with FBRs for producing weapons is that they produce significant quantities certain heavy plutonium isotopes (especially 240Pu) which are useless in weapons, and which in fact may cause a premature, low-yield detonation, or even a failed detonation. These isotopes fission either easily, or spontaneously, and would "pre-ignite" a bomb before it was fully assembled, causing at most a puddle of molten, no-longer-critical metal, rather than a nuclear explosion.''

That's got some true statements but it's generally barking up the wrong tree completely. Pu-240 contamination is certainly the main problem with using reprocessed reactor fuel for bombs, as described. But exactly the same problem occurs with PWR fuel. The main proliferation risk with FBR technology is that while the plute in the fuel is pretty useless for bombs, the stuff in the breeder blanket is pretty good, and if you have facilities to change the breeder blanket while on power it can be made as high-grade as you like without interupting the power generation activities. Andrewa 07:50, 28 Oct 2004 (UTC)

Why was the Economics section removed? I thought it was balanced and informative, and asks an important question: why aren't these breeders a bigger part of the nuclear economy any more, especially since they would appear to solve many of the worst problems of high level waste disposal? --Mike Van Emmerik 21:56, 10 September 2005 (UTC)


 * It was just a vandal. Feel free to revert when you see interesting material deleted.  --noösfractal 22:15, 10 September 2005 (UTC)

This page and others that include the Fermi I plant cite the power as 94 MW(e). Perhaps that was the original design power, but its actual gross output was 61 MW(e). (Reference: American Nuclear Society "World List of Nuclear Power Plants") Anuke (talk) 16:06, 6 August 2009 (UTC)

Move article
The article should be at Fast breeder reactor. Or it should be a section within Fast neutron reactor. Laurel Bush 14:57, 19 September 2005 (UTC).

The title should be 'Fast reactor'; it's a type of reactor that uses fast neutrons with highly-enriched fissile fuel. A 'Fast breeder reactor' is a modification, where the reactor is surrounded by fertile U-238 to create more plutonium fuel, the very fuel being burned in the fast reactor core. The article does not make this distinction clear. 82.40.252.131 14:43, 8 November 2006 (UTC)

Transmutation and politics
Removed from the end of "Associated reactor types": "The energy department later condemned the waste producing effects of these fuel reprocessing units, and accordingly shut down all Uranium plants that were deemed harmful to the environment." which was part of a vandalism by 24.97.156.194. At least, I assume it was part of the vandalism; it just reads silly to me. Surely breeder reactors consume long lived waste from ordinary reactors, and produce short lived waste, so even a politician couldn't use this reason to shut down breeders and not ordinary reactors. --Mike Van Emmerik 22:21, 18 October 2005 (UTC)


 * If they can assert (as some do) that nukes produce greenhouse gas, then they can assert anything. If they can shut down Barsebäck nuclear power plant on promises of not increasing greenhouse gas, then they can do anything. A diplomat's words must have no relationship to action, otherwise what sort of diplomacy is it? - Joseph Stalin. Politics, I'm afraid, has similar problems with the truth. Andrewa 17:20, 29 December 2005 (UTC)

Sodium, radiation and water
I took out this:-
 * ", therefore 2 sodium loops are required to prevent the contamination of the turbine water with the sodium 24"

Na*24 AFAIK doesn't spit neutrons, agrees (beta decay) so it will not poison a secondary water cooling loop - I think there are also other convincing reasons to not mix Na and water!


 * My reference was here I amn't too hot on nuclear physics so am willing to accept what you say, however there is still a Na / Water heat exchanger so this doesnt account for having a second loop. I was interested in finding out why there was the double loop, and if it isnt to do with Na 24, It would be nice to include why it is as otherwise it looks like complexity for the sake of it.


 * Sodium + water = bad. Radioactive sodium + water = worse.
 * "Sodium reacts chemically with air, and especially with water, which is a safety drawback. To improve safety, a secondary sodium system acts as a buffer between the radioactive sodium in the primary system and the steam or water that is contained in the conventional Rankine-cycle power plant. If a sodium-water reaction occurs, it does not involve a radioactive release."
 * THE SODIUM-COOLED FAST REACTOR (SFR)
 * —wwoods 17:39, 17 December 2005 (UTC)
 * that makes excellent sense. Is the primary loop entirely within the reactor containment, whereas the secondary loop can take heat far enough away to be convenient?  That would make another reason.  Midgley 21:30, 17 December 2005 (UTC)

Apologies for my physics gaffes, maybe someone could condense the above coherently into the page? Any comments about the DFR schematic let me know Emoscopes 05:13, 18 December 2005 (UTC) Another question that perhaps deserves an explenation in the article, why is it that the coolant flows into the top of a FBR and out at the bottom?


 * Please sign your posts on talk pages.

Some very perceptive comments above! At least part of the motivation (perhaps most of it) for the secondary sodium loop is the need to contain the entire primary coolant within a biological shield. Thus, Dounreay Fast Reactor had a separate neutron shield, inside its biological shield. A sodium leak or fire (probably one implies the other) is going to be embarrassing and difficult whether the sodium contains the short-lived sodium radioisotope or not.

One of the things the Brits did at Dounreay was to do live testing of the results of a pressure tube failure in a sodium-water heat exchanger; The French licensed (and paid for) the technology the Brits developed, and used it at Phénix and Superphénix. Andrewa 20:36, 3 February 2006 (UTC)

Other articles
See Talk:Fast neutron reactor. Andrewa 18:30, 29 December 2005 (UTC)

Removed text
After some soul-searching, I've removed the following section:

Carbon

A Plutonium cycle might reduce the Carbon emissions associated with preparation of fuel - Uranium refinement and enrichment from the lower grade ores which would be used in coming years requires considerable energy and diminishes the advantage fission power has over burning hydrocarbons in limiting greenhouse gas emission and consequent global warming.

Some of this is speculation, but it's entirely based on the false premise that nuclear power contributes to carbon emissions. It doesn't. Even before the development of the gas centrifuge, when significant power was required to drive gaseous diffusion enrichment plants, France managed to fuel all her power reactors, her nuclear submarines, run a weapons program, and export enriched uranium as well, all with a gaseous diffusion plant supplied by a four-unit PWR station. (And in fact the power requirements for the enrichment plant never reached two units, the rest was fed to the grid.)

Claiming that nuclear power requires burning of fossil fuel is an ingenious and sometimes successful political tactic, but it has no basis in fact. In some other parts of the world (notably the USA) enrichment plants are still powered by fossil fuel, but if these plants were to close the nuclear power industry would do very well without them. Andrewa 02:20, 30 December 2005 (UTC)

More removed text, from the section on Superphenix:

''the liquid sodium cooling system proved largely unwieldy. Superphénix was also the focus point of various groups hostile to nuclear energy.''

Come now! If the liquid sodium cooling system had really proved largely unwieldy, would the generation IV reactors, the BN-800 under construction, Monju, etc really be persisting with it? Certainly, it was 'bleeding edge' technology, and showed it. But it was remarkably successful.

As for being the focus point..., we should perhaps add like any other nuclear reactor. That's not really saying anything encyclopedic about Superphenix. Andrewa 01:51, 5 February 2006 (UTC)

BWR risk and article name
"It is generally agreed that—if designed incorrectly—the FBR poses a greater risk of proliferation of nuclear weapons than the PWR." What about boiling water reactors? Perhaps it should be changed to light water moderated reactors ("light" because the article says heavy water reactors may be able to be breeders).

Also, breeder reactor redirects here, but fast breeders are only one type of breeder reactor. Should a new article be started at breeder reactor, or should this article be modified and the article named changed (back) to "breeder reactor"? -- Kjkolb 07:04, 19 January 2006 (UTC)

Eeek! I've removed the if designed incorrectly. My guess is that it was added by someone who is pro nuclear power, as am I, but I can't imagine any justification for such a POV qualification. The FBR does have extra proliferation risk, owing to the fact that the probability of using a PWR (or BWR, you're quite right, it's just that PWRs are a bit more common) to provide bomb plute is near-zero (and the much-quoted non weapons grade test used plute from a magnox, not a PWR).

There's still some serious work required. POVs from both sides evident, and the result comes across to me as just plain confused. Andrewa 15:56, 3 February 2006 (UTC)

Move done.

I think the idea of a separate article at breeder reactor is an excellent one, as many people are probably unaware of the Indian direction and assume that all breeder reactors are FBRs, as this redir suggests. Andrewa 20:08, 3 February 2006 (UTC)


 * Perhaps Thermal breeder reactor? splitting from breeder reactor tot eh two with more or less discussion in common left at the junction page?Midgley 21:04, 3 February 2006 (UTC)


 * I think the first step is a high-level article at breeder reactor, to replace the current redir. Otherwise, we have a problem as to where this redir will point! Andrewa 21:15, 3 February 2006 (UTC)


 * Done. Andrewa 20:41, 4 February 2006 (UTC)

Diagram
I've ammended the DFR diagram as suggested, so that the coolant is NaK. One question that has puzzled me though, is why the reactor design appears to be "upside down", as in why is it that the coolant flows in through the top and the hot coolant leaves at the bottom? Other reactor designs iv'e looked at have the hot coolant leave the top of the reactor core. Is it that unusual? If it is, what is the reasoning, and should this be in the article? Emoscopes 11:39, 4 February 2006 (UTC)

PFR
I would also like to make a schematic diagram for the Dounreay PFR design. There are some good, if overly technical, schematics here http://www-frdb.iaea.org/react/pfr.html but they have posed me a couple of questions; Emoscopes 20:21, 5 February 2006 (UTC)
 * 1) Do other users think I should go into the complexities of the multi-stage heat removal plant? Or should I concentrate on the reactor itself.
 * 2) http://www-frdb.iaea.org/photos/pfr/cut_away.jpg this diagram shows what appears to be some rotating part of the core. From what I can make out from http://www-frdb.iaea.org/photos/pfr/discharg.jpg  ;
 * 3) when breeding has occured, the "charge machine" lifts the breeder subassembly out and into the rotor
 * 4) The rotor is cooled and then rotates in the core so that the breeder sub-assembly can be moved into a transfer flask
 * 5) This flask is then lifted out of the core and onto re-processing. Have I got this correct?
 * 6) I am presuming that the coolant in this case is Na, not NaK

Some replies:

1. I'd concentrate on the core itself, and the online refuelling machinery. That's the interesting bit.

2. There are two rotating bits:
 * The centre part of the top plate rotates, to locate the charge machine over any one of the assemblies in the core or surrounding breeder blanket. How the machine is moved radially is not obvious to me! There's some clever way of doing it that avoids the control rod mechanisms.
 * There's a temporary storage for both spent and new fuel assemblies, labelled the "rotor". The innermost position of this rotor is accessible to the charge machine. Assemblies can be loaded into, and removed from, the rotor via the transfer tube. When unloaded, they were placed into a transfer flask, as you say. Both fuel and breeder assemblies are loaded and unloaded in this fashion. The transfer flask may or may not have been used for loading unirradiated assemblies; On a DIDO class reactor for example, a similar flask is used for loading unirradiated fuel, just because the most convenient way to manage the contamination is to always have a flask on top of the reactor when anything goes in or out, and for every element that goes in one comes out so the flask needs to be there anyway.

3. The coolant is sodium. NaK (pronounced "nack") is the normal name for sodium-potassium alloys, particularly those liquid at room temperature. But, I suggest calling sodium "sodium" rather than giving it its chemical symbol Na.

I'm not convinced that http://www-frdb.iaea.org/photos/pfr/cut_away.jpg is entirely accurate. At the time DFR and PFR were built, there was obsessive secrecy about these programs (one of several reasons that DMTR was built at all rather than doing the work at Harwell). So some of these diagrams probably weren't done at the time (perhaps some were); There were no schematics drawn or released for publicity at that time, only highly-classified construction drawings, most of which would have been shredded when the British FBR program was running down (that's how the public service used to work).

These may rather be drawings done by the decomissioning team, who are publicly and sorely lamenting the fact that the designers and builders (now all long retired) didn't leave them better documentation, and who have very limited physical access to the machinery described owing to residual radioactivity.

http://www-frdb.iaea.org/photos/pfr/core.jpg and http://www-frdb.iaea.org/photos/pfr/reactor.jpg both have an authentic government-draftsman-of-the-time look. The others look more recent to me, and IMO may contain some guesswork, particularly in the still-to-be-decomissioned active areas. And even when these areas are cleaned up, documenting what they cut up will not be the highest priority. Hope this helps. Andrewa 23:15, 4 February 2006 (UTC)

SuperPhenix Shutdown
I was unabl;e to find a good source for the change made on March 23, 2006 -- was as close as I got to one. Does anyone have a source as r to why the SuperPhenix was shut down? Simesa 03:23, 24 March 2006 (UTC)
 * Try the article on SuperPhoenix. It should be in the list at the bottom of this article. J.Ring 10 September 2006 (UTC)

How much fuel does a breeder produce?
It is always mentioned that the breeders are a potential source of fuel for other reactors. What is never said is how much other reactors a breeder can supply with fuel. 1? 10? 0.5? This information should in some way be included at least for one or two of breeders that have been in operation.
 * It depends what you mean. Breeder reactors would obviously not need fuel from other reactors, so the only reason to build breeder reactors with breeding ratios above 1.0 would be if you wanted to fuel a lot of conventional reactors using a single or a few breeder reactors with high breeding ratio. In this case a breeder reactor could probably produce fuel for roughly 1-2 other reactors of similar power rating. However, this figure would depend greatly on the design of the other reactor as the conventional reactors would also breed some fuel ( They are not called breeders as they can't breed as much fuel as they consume, but they still produce some). As an example, if the breeding ratios of the conventional reactors were as high as 0.5 (and this is not too far fetched a figure ) they would only need about half of their fuel consumption replaced, meaning 2-4 reactors could be fuelled by the fuel from a single breeder reactor.


 * Note however that improved breeding ratios do not increase the total amount of energy that can be extracted once a breeding ratio of 1.0 has been achieved. This is because reactors with breeding ratios above 1.0 can burn all the fertile material, so the amount of available fuel does not increase by increasing the breeding ratio above 1.0, it would just allow you to consume uranium quicker, producing the same total amount of energy over a shorter period of time. Once a breeding ratio of 1.0 has been achieved, the total amount of energy that could be extrated from a closed fuel cycle could extract roughly 100 times as much energy as a once-through fuel cycle (since there is roughly 100 times as much U-238 as U-235 ). If in addition U-233 was made from Th-232 in thermal breeder reactors, this would put the figure up to about 400 times as much. All in all this could easily satisfy current trends in electricity consumption for centuries or more. J.Ring 00:58, 10 September 2006 (UTC)

OBS: I learned, when I was studying engeneering that breeding ratios was always larger than 1, when it was less it was called something else.Seniorsag (talk) 10:57, 5 July 2012 (UTC)

It is also called a "conversion ratio." If the ratio is less than one, the reactor is called a "burner." NPguy (talk) 02:06, 6 July 2012 (UTC)

Proliferation risks
The article currently seems to suggest that the reason FBRs are generally considered a greater proliferation concern is due to on-load refuelling, but surely the main increase in proliferation risk is due to the need for a reprocessing plant, and not because some designs might be able to refuel on-load? After all, many thermal designs (Rhapsodie, RBMK, CANDU, magnox ), do refuel on load, and could very well be used to produce weapons grade plutonium if operated by a country with reprocessing technology. Furthermore, several FBR designs ( such as the LFR ) have very long refuelling times ( decades ) and would be very expensive to operate at short cycles as the liquid metal coolant would require continuous heating. Thus it appears to me that the main reason FBRs are more of a proliferation concern is not due to on-load refuelling, but rather because reprocessing would be necessary in order to utilise their ability to breed fissile material. I will try to clarify this in an NPOV way, but I think the entire section could do with a rewrite. J.Ring 23:03, 9 September 2006 (UTC)


 * It depends on how you're doing reprocessing. PUREX is a risk because it can produce pure uranium and plutonium. Pyroprocessing wouldn't be, because it sweeps all the actinides together, which'd be much harder for a bomb-maker to work with.
 * —wwoods 02:55, 10 September 2006 (UTC)
 * Surely it would still be useable to extract plutonium from low-burnup reactors tho? After all, the low burnup keeps the amount of Pu-240 low ( bellow 4-6% ), so I'd imagine the minor actinides would be pressent in even lower amounts if the reprocessing technology was copied and used to extract plutonium from a low-burnup thermal reactor. I.e pyroprocessing when applied to fast breeder fuel may not be a problem, but the pyroprocessing technology might potentially be used to reprocess fuel from other reactors with much lower concentrations of actinides in the spent fuel ( Tho I agree it would be a much lower risk than PUREX reprocessing). J.Ring 17:41, 10 September 2006 (UTC)
 * Surely not. Pyroprocessing gives you two batches of uranium, plutonium, minor actinides and some lanthanide fission products all mixed together.  One of these batches contains mostly uranium, the other more of everything else, but none of the two can be considered "pure" in any conventional sense of the word.  A bomb needs chemically pure Pu.  This stuff is  dirty, so isotopic composition doesn't matter at all.  88.73.236.212 17:04, 23 September 2006 (UTC)

A small notice; usefulness for nuclear bombs do not depend on burnout but neutron irradiation (lengt of), bomb reprocessing can be used for power reactors but cheaper reprocessing needs long cooling before processingand are no god if you need the bomb soon!Seniorsag (talk) 11:04, 5 July 2012 (UTC)


 * This last comment seems garbled. Length of irradiation does not matter (much) compared to burnup.  The main factors are the neutron fluence (for which burnup is a reasonable surrogate) and energy spectrum, which determine the buildup of higher (particularly even numbered) plutonium isotopes.  Cooling time affects the ease of reprocessing but not the weapon-usability of the product. NPguy (talk) 02:11, 6 July 2012 (UTC)

LMFBR schematic
It appears to me that the "Loop Design" section of this schematic contradicts the text by having the primary loop extend outside the biological shielding. AfOrr 14:25, 2 December 2006 (UTC)

Use of `fission' as verb
This article contains several usages of phrases such as `[they]would spontaneously fission'. Is this correct?--Rossheth | Talk 23:56, 31 May 2007 (UTC)
 * I've rewritten to use `undergo fission' instead, which is somewhat better.--Rossheth | Talk 11:15, 1 June 2007 (UTC)

Merger proposal
Hi, I think the Generation IV reactor should be merged into this page. Basically, Generation IV is about fast breeders, only they are being called Gen IV because the term breeder rings the Dr. Strangelove bell. -- 85.125.140.110 (talk) 13:05, 7 March 2008 (UTC)


 * I disagree, the VHTR is not a fast reactor, nor is SCWR. While both reactors can breed some fuel, I don't think they would breed enough fuel to keep themselves running indefinitely.  The only reactor that is called a "breeder" reactor is the molten salt reactor, which uses thorium for the breeding, and thorium breeders are not fast spectrum.  While the "fast" reactors could be "breeders" if the core was made in the correct geometry and with the right materials, as I understand, they are primarily meant to be "burner" reactors, that is, reactors with a spectrum fast enough to eliminate the long lived transuranic fission products from other nuclear waste. Lcolson (talk) 15:01, 7 March 2008 (UTC)
 * Also the gen IV reactors are designed to have inherent safety features that rely on physical principles such as natural circulation to cool components in case of accidents. Lcolson (talk) 22:24, 7 March 2008 (UTC)
 * As a side note, your using the link to insinuate that the "nuclear industry" is trying to pull a "fast one" just from one persons comments (pulled out of context at that) is like me saying that all environmentalists support nuclear energy because one of the former heads of greenpeace now supports it . Lcolson (talk) 22:24, 7 March 2008 (UTC)
 * One of the goals of the GIF is to create, what they call 'sustainable' nuclear energy, and in this they understand that reactors breed their own fuel. On the SCWR: "A SCWR design could be developed with a fast neutron spectrum. Using fast neutrons with higher kinetic energies would enable the system to produce at least as much fissile material as it consumes (thereby fulfilling the sustainability goal as set out in the Generation IV roadmap)". The VHTR, however, does not comply with the goals of Gen IV itself. -- 14:00, 15 March 2008 (UTC)

Generation 4 reactors are not all necessarily breeders besides breeding fuel is hardly a classification of gen 4 generally considered to be reactor of high MWe/MWt ratio,more safe,produce less weight and involve considerable plant simplification due to advances of material science etc —Preceding unsigned comment added by 59.178.162.129 (talk) 18:00, 4 May 2008 (UTC)
 * Lcolson removed the merger proposal, as he stated consensus was reached. There has been comments of Lcolson, one anonymous, and me, and I don't think the outcome (which?) qualifies as consensus. -- Eiland (talk) 11:59, 13 June 2008 (UTC)


 * Try to push your POV all you want. Anyone doing any research on the topic will see that the definitions of fast breeder reactor are not the same as Gen4 reactor.  It is simply fact, there is nothing to argue about.  Fast breeder reactors must have a fast neutron spectrum, that is inherent in their definition, google it.  I don't know why you're focused on uniting these two different topics, but I suspect its from your desire to try to lump Gen4 systems in with the "dreaded plutonium economy" as appears evident form your first comment.  This should be brought to arbitration if you don't agree, since this is about a clear definition and should be easily remedied.  Here's a link from the Gen4 forum that states the SCWR may have a thermal spectrum http://www.gen-4.org/Technology/systems/scwr.htm this alone proves definitively that the GEN4 reactors are not all fast and should not all be categorized as so.  Here's another for the VHTR http://www.gen-4.org/Technology/systems/vhtr.htm clearly stating that it is a thermal system.  Here's one for the molten salt reactor http://www.gen-4.org/Technology/systems/msr.htm that clearly states that it can be a epithermal-spectrum reactor   Note: these are from the actual generation 4 forum that the article is about.  I think if 50% of the reactor designs arn't necessarily fast, you it would be a major error to call them so.  —Preceding unsigned comment added by Lcolson (talk • contribs) 14:13, 13 June 2008 (UTC)


 * If you desire more weight to be put to the decision by more contributors, so be it. I agree fully with Lcolson: it is obvious even from the Gen4 article alone that Gen4 comprises much more than fast breeders. Only the reverse, merging fast breeders into Gen4, could be a theoretical option, but then I think the fast breeder concept is much older (late 60s) than Gen4. In conclusion, I am strongly in favour of removing the merger proposal. --Sesc (talk)  —Preceding comment was added at 09:06, 15 June 2008 (UTC)


 * It appears that Eiland is has an anti-nuclear POV and is engaged in edit wars on other nuclear pages (see his talk page). Any edits he makes here and on the Gen4 page are probably circumspect. Lcolson (talk) 02:52, 17 June 2008 (UTC)


 * Whats new about that? Everyone has a point of view, and I strive to make wikipedia a neutral source and relevant source of information, just like I assume you do. Removing my merger proposal without awaiting further discussion goes against WP philosphy, and I strongly object. -- Eiland (talk) 10:55, 17 June 2008 (UTC)


 * Eiland, that is a red herring. Looking at this "discussion" and other ones you have been involved in, it is apparent that you are not discussing anything.  We have made points ,counter points to yours, and backed them up with good neutral references.  You have not made any logical counter points that address ours.  And the idea is to keep POV out of articles, not have your POV balance ours.  The idea is not to have POV in articles to begin with.  When I write, I try to keep my writing as factual as possible.  Your point is purly based on your opinion, where as mine, Sesc, and Nailedtooth's were based on fact.  You claim to be discussing stuff, but you are not.  I have seen editing like this before, and it always ends in a ban.  I wouldn't bee surprised if you were a sockpuppet of someone who infact was banned (like Ben who got banned from editing Nuclear Power).  I am not going to try too hard to explain this anymore to you, because you might be a sockpuppet who is just wasting my time.  Edit in good faith or be prepared to have your edits removed.  Lcolson (talk) 11:37, 17 June 2008 (UTC)


 * Im sorry, I reported this at the Admins noticeboard. I cannot continue participating in this project if I'm treated like this. -- Eiland (talk) 12:03, 17 June 2008 (UTC)


 * Good. Nothing to be sorry about.  Hopefully this leads to a quick resolution.  Lcolson (talk) 12:31, 17 June 2008 (UTC)


 * Oppose merger. The focuses of the two articles are legitimate, and manifestly different. Remove merger proposal -- it's a non-starter.  Jheald (talk) 13:49, 17 June 2008 (UTC)


 * Oppose merger. It seems obvious: Gen-4 designs are not all fast breeders (nor all fast, nor all breeders). And conversely, not all fast breeder designs are Gen-4 — *no* existing fast breeders are Gen-4 designs. —WWoods (talk) 16:01, 17 June 2008 (UTC)


 * Oppose merger. Not all Gen IV are fast breeders. Even if they were Gen IV would still merit its own article to compliment Gen II and III articles. Also, it makes sense to separate an article about a reactor concept (fast breeder) from articles about specific designs that use that concept (some Gen IV et al). Nailedtooth (talk) 05:28, 18 June 2008 (UTC)


 * I still believe that Gen IV is a hollow marketing phrase, bundling random types of nuclear reactors together, most of which have fast breeder properties, which doesn't merit an individual article, but we've spent enough time on this, so I retract my merger proposal. -- Eiland (talk) 11:21, 18 June 2008 (UTC)

Uranium-233 not so handy for bombs

 * 233U is arguably not a serious proliferation concern because of the associated uranium-232 (from thorium) and its powerful gamma radiation. It's a chicken and egg problem. Only nations that already have nuclear weapons would likely have the remote handling expertise to make a 233U bomb. Of course, a fanatical government could conceivably sacrifice workers lives, but the educated engineers required would be unlikely to go along. Anyway, it should be presented as a more debated point. Anthony717 (talk) 02:42, 23 March 2008 (UTC)
 * Also, see "Definition of Weapons-Usable Uranium-233" by Oak Ridge National Laboratory.
 * In fact, the section about Thorium seems to me to be completely at odds with this lecture: http://www.youtube.com/watch?v=AHs2Ugxo7-8 - I'm not an expert on this subject, so I don't think it's my place to make changes to the article, but for someone with more expertise in the subject, this might make a good source (as I believe the guy is fairly well regarded). Andipi (talk) 17:27, 13 December 2008 (UTC)

Reactor Functioning Info?
There's very little information in this article on how a fast breeder reactor actually works, its basic design, how it produces fuel, what fuel it produces. There are some diagrams, but nothing to explain what information is in those diagrams. Some information on this would go a long way to making this article more informative. —Preceding unsigned comment added by TV4Fun (talk • contribs) 05:57, 8 April 2009 (UTC)

Thorium, U233 and U232; Short-Shrift on Thermal Breeders;  Semantics of "Fast Reactor",  "Fast Breeder" and "Breeder"
I don't agree with the content about the proliferation risks of U233. The issue is that the production of U233 from Th232 involves the immediate production of Pa233. When Pa233 is in a neutron field, it undergoes a spallation reaction that produces U232. I'm not sure if U232 poses a predetonation problem like Pu240, but it does have strong gamma emitters in it's decay chain that make it difficult to fabricate fuel and weapons from U233 that is contaminated with U232. Weapons-grade U233 can be created, just like weapons-grade Pu,  but it requires short cycles in the reactor (or a highly-effective Pa removal system in a molten-salt reactor.)  The lower breeding ratio on the Th cycle also means that thermal breeders will produce less excess material than Pu breeders could. Many authorities believe that a Th cycle is a lower proliferation risk than a Pu cycle, but that all depends on future technological developments.

Three kinds of thermal breeder have been seriously considered (Molten salt, the LWR-derivative design successfully tested at shippingport,  and the heavy water types researched by the Canadians.)  None of them are on topic for this article because they're not "Fast" reactors:  a really brief link to a "thermal breeder" article may be appropriate.

Epithermal reactors such as the RWMR and SCWR can probably be claimed to be fast.

If you're going to reorganize the content, make sure you've got a good ontology. A "Breeder" reactor is a reactor with conversion ratio >1. Breeders can be fast or thermal. Note that a fast reactor doesn't need to be a breeder: fast reactors can be designed that consume actinide materials without producing them:  for instance,  you can replace U238 or Th with an inert matrix.

"Fast Reactor", "Fast Breeder Reactor",  "Breeder Reactor" and "Thermal Breeder Reactor" all seem legitimate topics. Splitting content up between "FR" and "FBR" looks like the toughest challenge —Preceding unsigned comment added by 208.105.253.90 (talk) 17:16, 10 June 2009 (UTC)


 * I was going to disagree about the proliferation risks of U-233, but when I read the article I changed my mind. It is fashionable in some quarters to downplay the proliferation risks of U-233, but this article does the opposite in claiming that the thorium fuel cycle may pose a higher proliferation risk than a uranium fuel cycle.  Because the hard gammas from the U-232 decay chain make the resulting uranium harder to handle, the risk is probably comparable.  Of course, a closed fuel cycle has a higher proliferation risk than once through, but both the thorium and uranium fuel cycles can operate without reprocessing - the former by using mixed U-Th fuel and breeding in U-233 in situ.