Talk:Integral fast reactor

fuel efficiency

The 3% burn rate is misleading. While 3% of the enriched fuel stuffed into a pressurized water reactor may be consummed - one has to look as well at the amount of fuel that goes through the enrichment process. When one takes this into consideration the amount of mined uranium which is burned is less than 1%.

Whoever wrote the section should do these numbers and make this clear. This misinformation would lead one to conclude that we can get about 30x the milage from the uranium mined. In fact we can get 300x to 1000x the milage (it depends on the residual U235 left in the "depleated" fraction).

I just corrected it to "less than 1%", which is about right, considering that at best 0.7% of natural uranium are fissile and some additional plutonium is bred and fissioned and current fuel cycles are less than optimal. A breeder should give about 60x more fuel efficiency than a light water reactor with multirecycling; more conpared to once-through. (But I never heard numbers like 300x or 1000x before.)

You corrected it worng. The numbers I gave you are correct. The first error is the 1% figure. While with natural uranium we are dealing with 0.7% fissle material (U235) some of the neutrons transmute the U238 into PU239/PU240. This is also fissle and ends up burning. Next in the high pressure reactor designs we are using an enriched fuel. If you check the process used to enrich fuel, you will find the cacades in general are not much more than 50% efficient. Hense to end up with say a 5% enriched fuel the 0.7% U235 we start with ends up reduced to about 0.3% in the depleated fraction. Thus you need to dump in 2x as much natural uranium in order to obtain the enrichment you want and literally 1/2 of the U235 fraction ends up in the depleated pile. Let me demonstrate: Suppose you want 5% U235. In order to get this if you started with 2000 lbs of natural uranium you would have 0.7%*2000 = 14 lbs U235. You can combine this with 266lbs U238 to yeild a total of 14+266 = 280 lbs of 5% enriched fuel. To confirm 14/280 = 5%. But 1/2 of the U235 ends up in the depleated pile if our cascades only salvage 1/2 of the U235 in the natural uranium. So you end up with 7 lbs U235 in a total of 140 lbs of U235+U238. 140/2000 = 7%. IE 93% of the mined uranium is discarded. Next you burn only 3% of the 140 lbs so that means you burn 140*0.03 = 4.2 lbs. 4.2/2000 = 0.21%. IE you have discarded 99.79%. 99.79/.21 = 475x. If you burn all of the mined uranium you will get 475x the milage. The bottom line is that it is fairly simple to compare the tonnage you start with compared to the amount actually burned and you will find that it is not very much. Quite literally only about 0.2% of the starting uranium ends up being burned and of course most of this is the U235 fraction. The 300x-1000x number is pretty close and I have shown you how to calculate it. terr 13:29, 16 May 2006 (UTC)[reply]

Less than 1% is still correct. It stays correct even with more thorough enrichment (which is possible, but expensive) and it is still a good estimate even considering multirecycling. So we get a 60-fold improvement over an idealized LWR and maybe 200-fold over currently practiced idiocy (which will stop as soon as uranium gets scarce). Second, a calculation with invented numbers isn't all that convincing. Iirc, LWRs run at about 3.5% enrichment and leave only about 1% U235 in the so-called spent fuel.

LWR's do run at 3.5% U235. But the fuel input can be higher. Some reactors such as for Nuclear Subs run at much higher enrichment - up to 80%. It is correct to say that the spent fuel contains about 1% U235. It also contains about 1% Pu. Thus the fissle fraction of the spent fuel is about 2% which is about 3x higher than what a CANDU reactor would start with. The spent fuel from a CANDU is about 0.5% U235. terr

Add in the possibility of breeding U-233 from Th-232 and you could multiply the amount of available fuel by another factor of 4 or so. 137.205.192.27 17:30, 10 September 2006 (UTC)[reply]

NPOV

I'm not so sure that this entry complies with the NPOV requirement. I intend to research this topic more fully and attempt to moderate its view point. —Preceding unsigned comment added by 198.232.60.10 (talk • contribs)

I hope your research has reassured you, as you don't seem to have made any edits to the article! Andrewa 01:35, 22 June 2007 (UTC)[reply]

Is it time to remove the NPOV tag? The advantages section was rewritten as a more balanced comparison section. 155.212.30.130 (talk) 21:04, 16 December 2009 (UTC)[reply]

Waste

What is the actual waste product from these kinds of reactor? What actually leaves the facility? —Ashley Y 05:13, September 13, 2005 (UTC)

The fission products. Various isotopes of various elements produced by splitting uranium atoms. The highly-radioactive stuff, which therefore decays relatively quickly.[1]

—wwoods 08:19, 13 September 2005 (UTC)[reply]

What are the isotopes? What are their half-lives? I assume the difference is that the waste doesn't include any uranium or plutonium. —Ashley Y 08:26, 13 September 2005 (UTC)[reply]

"Using U-235 in a thermal reactor as an example, when a neutron* is captured the total energy is distributed amongst the 236 nucleons (protons & neutrons) now present in the compound nucleus. This nucleus is relatively unstable, and it is likely to break into two fragments of around half the mass. These fragments are nuclei found around the middle of the Periodic Table and the probabilistic nature of the break-up leads to several hundred possible combinations. Creation of the fission fragments is followed almost instantaneously by emission of a number of neutrons (typically 2 or 3, average 2.5), which enable the chain reaction to be sustained.

[graph of bi-lobed distribution of atomic masses of fission products][2]

"The number of neutrons and the specific fission products from any fission event are governed by statistical probability, in that the precise break up of a single nucleus cannot be predicted. However, conservation laws require the total number of nucleons and the total energy to be conserved. The fission reaction in U-235 produces fission products such as Ba, Kr, Sr, Cs, I and Xe with atomic masses distributed around 95 and 135. Examples may be given of typical reaction products, such as:"

http://www.uic.com.au/uicphys.htm

"Before discussing solutions, however, let's consider the problem . The intense radioactivity of the waste produced in a nuclear reactor comes from two sources: (1) light nucleus fission products consisting mainly of elements 38 (strontium) through 67 (holmium) and (2) transmuted heavy nuclei consisting mainly of actinide elements 90 (thorium) through 96 (curium).

"The light nucleus component of nuclear waste is made when uranium or plutonium reactor fuel splits (or fissions) with considerable energy release into two lighter nuclei. These fission products typically have too many neutrons for stability, making them highly radioactive as their excess neutrons are converted to protons through beta decay (emission of an electron and an anti-neutrino).

"The heavy nucleus component of nuclear waste is made when the uranium or plutonium reactor fuel is transmuted to heavier elements by neutron-induced reactions that do not lead to fission. The resulting heavy nuclei tend to be radioactive through the process of alpha-decay (emission of a helium-4 nucleus). They decay toward stability in a linked sequence of alpha and beta decays called a "decay chain", the completion of which requires about 100 million years.

"The decay rate of a radioactive nucleus is specified by its half life, the time required for half of a sample of radioactive nuclei to decay. It is a remarkable accident of nature that nuclear waste contains no important fission product isotopes with half lives between 90 years and 70,000 years. Therefore nuclear waste can be considered to consist of a heavy nucleus actinide component A, a short-lived light nucleus component B with half-lives less than 90 years, and a long-lived light nucleus component C with half-lives greater than 70,000 years. The radioactivity of component A is dominated initially by the actinides 244Cm (half-life 18 years), 243Am (7,380 years), 238Pu (87 years), and 241Am (432 years). Component B is dominated initially by the fission fragment isotopes 137Cs (half-life 30 years), 90Sr (29 years), 106Ru (1.0 years), and 134Cs (2.1 years). Component C is dominated by the fission fragment isotopes 99Tc (half-life 214,000 years), 93Zr (1,500,000 years), 135Cs (2,300,000 years), and 129I (15,700,000 years).

"When the nuclear waste is first produced, the radioactivity from component B produces about 99% of the overall activity level, the radioactivity from component A is about 1% of the overall activity level, and the radioactivity from component C is only about one millionth of the overall activity level. After about 300 years the short-lived isotopes of component B decay away. After this the radioactivity from component A is the dominant source of radioactivity and is always greater than that of component C by a factor of 10 to 100.

http://www.npl.washington.edu/AV/altvw79.html

Of course, reprocessing strips out the Actinide component

—wwoods 20:18, 13 September 2005 (UTC)[reply]

A very quick calculation is as follows:
For the UK, the country-wide power consumption is approx 100GW. Using E=mc^2, we need to convert 35kg/year of mass into energy. Actually, U-235 fission yields about 0.1%, so we have about 35 tonnes of waste, per country, per year. This has to be kept for 300-500 years. Storage requires a moderate amount of security, building maintenance, and prevention of leaks into the environment. Thus, the IFR really doesn't pose a serious waste problem.
—Preceding unsigned comment added by RichardNeill (talk • contribs) 08:32, 29 April 2007

Doppler coefficient and delayed neutrons

I don't understand the claim that the high conductivity of the (metallic) fuel is a safety advantage. I would intuitively believe the opposite: if the heat is dispersed rapidely, then the temperature does not change so much even in case of a power increase, and this is bad. In conventinal reactors, the temperature increase of the fuel increases the probability that neutrons are captured through the U-238 resonances which are broadened by doppler effect, and thus it is important for inherent reactor safety (increase in power leads to increase in temperature which leads to power decrease...).

Another aspect which is not discussed here is the effective fraction of delayed neutrons. Most trransuranic elements have threshold fission cross sections, which make delayed neutrons less effective. Certainly, after the fuel is recycled a few times, the fuel composition will reach an equilibrium, with an important fraction of transuranic elements; but then, the reactor will be more unstable than conventional reactors because the effective fraction of delayed neutrons would be lower. This is one of the reasons why people consider subcritical reactors for the transmutation of the transuranic elements. --Philipum 14:21, 15 December 2005 (UTC)[reply]

If the fuel is conductive, then the total inventory of heat is less. In addition, the faster this heat goes to expanding the core, the faster the negative reactivity occurs. Doppler broadening does not have much effect in a fast reactor.

I believe that most the interest for subcritical reactors is for dedicated burning of actinides other than Uranium and Plutonium. With the IFR, they are mixed with plutonium and a small fraction of the total fuel. The properties of Pu-239 dominate the reactor. pstudier 15:23, 15 December 2005 (UTC)[reply]

I am dumbfounded

This seems to good to be true. However, I know the plant existed. Don't people understand those implications? It's equivalent to the Department of defense killing ARPANET! Where is the "I told you so" and outrage over this? I support terrorists everytime I buy gasoline...and yet if we had this we may not even need to import oil! Is this characterization exaggerated? RMartinez

Relax RMartinez, the IFR is being reborn as we speak as the Advanced Burner Reactor, check out the Global Nuclear Energy Partnership program for details. Good ideas never truly die!

Well, there is not much overlap between gasoline and nuclear. The US burns very little oil for electricity. Most electricity is from coal, natural gas and nuclear. Only golf carts and fork lifts run off of electricity. Until about a year ago, uranium was cheap so people lost interest in breeders. In the entire history only 50,000 tons of high level waste have been generated, and 40,000 tons of this would fit in dry storage on 120 acres on Goshute land. So waste is not a real big problem. Paul Studier

I talked about the oil because Nuclear power plants can make the hydrogen needed for next-generation cars. Also, many environmentalists have forced us to use coal because solar and wind (while useful) simply can't meet the demand, only nuclear can do that. Their biggest talking point is waste from nuclear. However, I don't know the political climate for nuclear as of now. RMartinez

Hydrogen is a scam. See The Hype about Hydrogen. Paul Studier 07:23, 9 August 2006 (UTC)[reply]

Hydrogen is far from a scam, if produced by electrolysis from nuclear powerplants hydrogen powered cars would produce no greenhouse emissions, no acid rain, no carbon monoxide, no cancer causing hydrocarbons etc... It is true that it has been hyped up a bit tho. In particular the difficulties in storing it, the enormous financial investment needed to set up a hydrogen economy, and the, at present, rather short lifespan of fuel cells have been downplayed. However, all of these are problems which appear to be solveable within a few decades. Several car companies already have hydrogen powered prototypes. All in all H2 powered cars are likely to start becoming important in about 30 years or so. They have some way to go still, but they are far from a scam. 137.205.192.27 17:25, 10 September 2006 (UTC)[reply]

"cancer causing hydrocarbons" =hilarious —Preceding unsigned comment added by 70.56.239.57 (talk) 16:48, 24 March 2011 (UTC)[reply]

Why is replacing the current infrastructure, including all the cars, a better plan than just gradually moving from an Ethanol/Gasoline mix to a Biodiesel/Plugin-Hybrid model? It seems like a giant waste of money. 129.63.28.113 18:53, 20 December 2006 (UTC)[reply]

Biodiesel is CO2 neutral, but it still emits other pollutants, such as carbon particles, sulfur and nitrous oxides that contribute to acid rains etc... With hydrogen fuel cells the only emission is water. Furthermore, biodiesel will require vast areas of land to grow the crops for the fuel, unlike hydrogen which can readily be produced from water using electrolysis. Thus hydrogen is more scalable, and less likely to contribute towards deforestation. 194.117.188.248 23:51, 27 December 2006 (UTC)[reply]

It's a 'Scam' in that it isn't practical. Hydrogen is very difficult to contain and move. For example, the piping used to move natural gas to a home to day would leak hydrogen, so all that needs to be changed out for a much more expensive to and harder to maintain piping. Electric is where vehicles will be in 15 years. You are correct, biodiesel can not work on a large scale either. IFR(ABR) and Industrial solar thermal is where the future is. —Preceding unsigned comment added by 209.162.223.250 (talk) 22:09, 4 September 2009 (UTC)[reply]

...but there is overlap between nuclear and gasoline: given hydrogen made with nuclear power, coal can be converted into oil, whereby most of the energy input comes from the hydrogen. Going a step further, oil can also be made from nothing but water, air and nuclear heat. There may be better options than that for powering vehicles, though. BTW, Paul, here in Europe, we have quite a lot of nuclear powered vehicles. We call them "electric trains".

If we could change over to using hydrogen to power all vehicles, would that really be such a good idea in terms of global warming and the environment? How much water would be introduced to the environment every year and where would it go? If emitted as warm or hot vapour, which could rise in the atmosphere, then it's worth remembering that water also is a greenhouse gas. I'm not sure how it compares to CO2, but we simply be exchanging one cource of global warming for another. And if it doesn't rise into the atmosphere but condenses onto the surface, then how much groundwater per year would we be adding? Zenkev 00:14, 17 February 2007 (UTC)[reply]

A person who drives to work might consume a gallon or two of gasoline. If he burned hydrogen, very approximately he would produce a gallon or two of water. Not too much more than he would produce from burning the gasoline. By comparison, I sometimes use hundreds of gallons of water a month to water the plants in my yard. Shouldn't be a problem. Paul Studier 00:32, 17 February 2007 (UTC)[reply]

Superphénix

Isn't this the same reactor design as Superphénix?

If so, then Superphénix should be mentioned in addition to the US prototype. It would also bring more data on the possible drawbacks of the design. And if not, it may be worth mentioning what makes it different from this other sodium based reactor design, and maybe from fast breeder reactors in general. Fgouget 17:23, 3 June 2007 (UTC)[reply]

It is a sodium cooled fast reactor. However, the emphasis on the IFR is on the whole fuel cycle and the use of on site Pyroprocessing. Paul Studier 23:03, 3 June 2007 (UTC)[reply]

Another key difference is that the IFR uses metallic fuel (elemental), whereas Superphenix (IIRC) uses oxide fuel. This is very significant for reprocessing: there is no reduction/oxidation step.

Initial Fuel

So the reactor can re-use fuel, but does anyone have data on what it needs to be charged with? I'm specifically interested in the U235/U238 ratio ... can it use natural abundance? -- 01:07, 22 June 2007 (UTC)

Not initially, like all fast reactors it needs enriched uranium and/or plutonium in the initial fuel charge. But it can use natural abundance as feedstock from then on. Andrewa 01:39, 22 June 2007 (UTC)[reply]

POV again

Current article reads:

(Currently, companies building nuclear reactors do not bear the costs associated with long-term storage of transuranic waste. If these costs were passed on to the industry, IFR would become more financially competitive.)

I think that the first statement is quite simply false. Practice varies from country to country, but in the USA, for example, there's a surcharge levied on every megawatt-hour produced to cover these costs. This is typical of practice in most of the world. There is some controversy over how much should be charged; For the antis, no amount of provision would be adequate, while many advocates of nuclear power (including myself) see the existing charges as being on the high side already, leading to a culture of overdesign and overregulation as the money is there to pay for it.

My suspicion is that this false statement comes originally from anti-nuclear propaganda of some sort. But there is possibly a valid point being made in the second sentence, and I'm not quite sure how to rephrase it, without introducing my own POV. Anyone else like to try? Andrewa 01:53, 22 June 2007 (UTC)[reply]

Why sodium?

Can anyone explain why the specific choice of coolant is sodium? I understand the need for a metal with low-ish melting point, but surely some other metal eg Gallium would also do, and be considerably safer? —Preceding unsigned comment added by 87.194.171.29 (talk) 15:12, 13 October 2008 (UTC)[reply]

There are several advantages to sodium - it has very short term radioactivity (~15h half time) which results from activation by neutrons, has low neutron absorption and scattering x-section, conducts heat very well, is cheap, and also has a low melting point.

Sodium is actually quite safe, if handled correctly, namely use double walls, run the reactor under an inert gas atmosphere, and keep the water away from the reactor. There is really no problem mastering that, as shown by many decades of successfully running such reactors (BN-350, BN-600, Rhapsodie, Fenix, etc) 24.45.165.89 (talk) 04:03, 3 December 2008 (UTC)[reply]

References

This appears to me to be a good article written by knowledgeable people, but it lacks citations to WP:RS reliable sources. I can't find sources myself, but if someone else can find sources, I am willing to help insert citations into the article. --Dr.enh (talk) 23:32, 13 July 2009 (UTC)[reply]

POV flag

I just added the POV flag in response to the extensive recent edits that make this article read like propaganda for IFR rather than a dispassionate description of the system. In particular, the theoretical/potential benefits need to be balanced against the practical challenges of realizing them. In addition to lacking balance, most of the recent additions lack citations. NPguy (talk) 02:35, 21 July 2009 (UTC)[reply]

Agreed, much of this sounds like a commercial to me. I would suggest that much of the comparison section and all of the un-cited Efficiency and Carbon Dioxide sub-section could be removed. I am in no way knowledgeable about this particular subject to feel comfortable editing these myself. Ngaskill (talk) 17:01, 23 September 2009 (UTC)[reply]

I would oppose deletion. This stuff needs to be sourced, but I believe that most of it is true. Paul Studier (talk) 22:59, 23 September 2009 (UTC) I've added a lot of balancing material and additional detail. The pro-IFR material can be tightened up further. --JWB (talk) 18:06, 24 September 2009 (UTC)[reply]

I definitely agree that this article (still) reads like an argument and PR piece on "why IFRs are good", "why we NEED nuclear power" etc. etc. etc. as opposed to simple factual statements on this reactor type. Centerone (talk) 07:09, 20 April 2010 (UTC)[reply]

"Key Advantages" "Key Disadvantages" replaced with "Comparisons to light-water reactors"

The Advantages section had a lot of repetition. I consolidated most of them and got rid of those that didn't add anything. We might need someone to go in and get rid of the duplicates left over from the Disadvantages.

I tried to combine the advantages/disadvantages into several categories. I did a lot of moving around, so we probably need someone to go in and fix the voice. Might need some more 'citation needed's, too. I Think I'm So Smart (talk) 18:10, 31 August 2009 (UTC)[reply]

The final paragraph under the "Nuclear waste" section here is a quote from a US Congress survey on the subject -- from what I can gather from that report the "others" referenced are a pair of scientists in commentary on the subject. Is there some way of noting that here that the "others" are exactly two people. It's not possible to just make equivalent references since the references from the report look like they were done through a request for comments for the report. 155.212.30.130 (talk) 15:45, 21 April 2010 (UTC)[reply]

Hypothetical

Much of the article refers to IFR reactors as if they actually exist. All of these should be changed to something like "The IFR design would ..." 22:29, 15 November 2010 (UTC)

I agree. I also think many of the supposed benefits have been demonstrated in an R&D context, but not at a practical level. NPguy (talk) 03:29, 16 November 2010 (UTC)[reply]

What did IFR achieve ?

Not clear from intro or rest of article what the project achieved, and what it was intended to achieve. It says it was canceled 3 years before completion. What stage design or construction was achieved, and what should have been achieved at completion ? Rod57 (talk) 13:26, 26 March 2011 (UTC)[reply]

Benefits and drawbacks from Na cooling

In this section, among benefits it's stated that sodium: "... Maintains an oxygen (and water) free environment protecting other components from corrosion. ..." and among drawbacks that there's a risk of "Spontaneous combustion with air (oxygen) and water..." This doesn't seem clear at all. How does it maintain an oxygen and water free environment other than by incentivizing: "If you DON'T keep it oxygen- and water free, you get big explosions!" If that's the case, it's hardly a real benefit.

Sarah (talk) 12:13, 29 March 2011 (UTC)[reply]

It will react with any traces of oxygen and water to make sodium oxide or sodium hydroxide and hydrogen. Trace amounts will not cause explosion. Paul Studier (talk) 17:47, 29 March 2011 (UTC)[reply]

I've tried clarifying that section as per your explanation. Please have a look at it as it is now. I'm still dissatisfied with "Reactions with water produce hydrogen" in the drawbacks section. --Sarah (talk) 10:03, 30 March 2011 (UTC)[reply]

I don't know if liquid sodium will spontaneously ignite in air. Probably depends on the temperature. Paul Studier (talk) 04:23, 31 March 2011 (UTC)[reply]

POV

I can imagine that if you oppose nuclear energy altogether, and haven't done any research on fast reactor designs, seeing the facts about the IFR might make you uncomfortable. Because the advantages of this concept are readily apparent.

Anyway, here are some materials about the IFR:

Whether you oppose or support nuclear energy, it should be possible to write factually about the IFR without trying to inject your personal opinion. However, if you feel very strongly one way or the other, it might be best to leave the editing to others.

76.1.37.196 (talk) 19:40, 16 April 2011 (UTC)[reply]