breeder reactor

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Breeder reactor Assembly of the core of Experimental Breeder Reactor I in Idaho, United States, 1951 A breeder reactor is a nuclear reactor capable of gener- ating more fissile material than it consumes. [1] These de- vices are able to achieve this because their neutron econ- omy is high enough to breed more fissile fuel than they use from fertile material such as uranium-238 or thorium- 232. Breeders were at first found attractive because their fuel economy was better than light water reactors, but in- terest declined after the 1960s as more uranium reserves were found, [2] and new methods of uranium enrichment reduced fuel costs. 1 Fuel efficiency and types of nu- clear waste Breeder reactors could, in principle, extract almost all of the energy contained in uranium or thorium, decreasing fuel requirements by a factor of 100 compared to widely- used once-through light water reactors, which extract less than 1% of the energy in the uranium mined from the earth. [8] The high fuel efficiency of breeder reactors could greatly reduce concerns about fuel supply or energy used in mining. Adherents claim that with seawater uranium extraction, there would be enough fuel for breeder re- actors to satisfy our energy needs for 5 billion years at 1983’s total energy consumption rate, thus making nu- clear energy effectively a renewable energy. [9][10] Nuclear waste became a greater concern by the 1990s. In broad terms, spent nuclear fuel has two main components. The first consists of fission products, the leftover frag- ments of fuel atoms after they have been split to release energy. Fission products come in dozens of elements and hundreds of isotopes, all of them lighter than uranium. The second main component of spent fuel is transuranics (atoms heavier than uranium), which are generated from uranium or heavier atoms in the fuel when they absorb neutrons but do not undergo fission. All transuranic iso- topes fall within the actinide series on the periodic table, and so they are frequently referred to as the actinides. The physical behavior of the fission products is markedly different from that of the transuranics. In particular, fission products do not themselves undergo fission, and therefore cannot be used for nuclear weapons. Further- more, only seven long-lived fission product isotopes have half-lives longer than a hundred years, which makes their geological storage or disposal less problematic than for transuranic materials. [11] With increased concerns about nuclear waste, breeding fuel cycles became interesting again because they can re- duce actinide wastes, particularly plutonium and minor actinides. [12] Breeder reactors are designed to fission the actinide wastes as fuel, and thus convert them to more fission products. After "spent nuclear fuel" is removed from a light water reactor, it undergoes a complex decay profile as each nu- clide decays at a different rate. Due to a physical oddity referenced below, there is a large gap in the decay half- lives of fission products compared to transuranic isotopes. If the transuranics are left in the spent fuel, after 1,000 to 100,000 years, the slow decay of these transuranics would generate most of the radioactivity in that spent fuel. Thus, removing the transuranics from the waste elimi- nates much of the long-term radioactivity of spent nuclear fuel. [13] Today’s commercial light water reactors do breed some new fissile material, mostly in the form of plutonium. Be- cause commercial reactors were never designed as breed- ers, they do not convert enough uranium-238 into pluto- nium to replace the uranium-235 consumed. Nonethe- less, at least one-third of the power produced by com- mercial nuclear reactors comes from fission of plutonium 1

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Breeder reactor

Assembly of the core of Experimental Breeder Reactor I in Idaho,United States, 1951

A breeder reactor is a nuclear reactor capable of gener-ating more fissile material than it consumes.[1] These de-vices are able to achieve this because their neutron econ-omy is high enough to breed more fissile fuel than theyuse from fertile material such as uranium-238 or thorium-232. Breeders were at first found attractive because theirfuel economy was better than light water reactors, but in-terest declined after the 1960s as more uranium reserveswere found,[2] and new methods of uranium enrichmentreduced fuel costs.

1 Fuel efficiency and types of nu-clear waste

Breeder reactors could, in principle, extract almost all ofthe energy contained in uranium or thorium, decreasingfuel requirements by a factor of 100 compared to widely-used once-through light water reactors, which extract lessthan 1% of the energy in the uranium mined from theearth.[8] The high fuel efficiency of breeder reactors couldgreatly reduce concerns about fuel supply or energy usedin mining. Adherents claim that with seawater uranium

extraction, there would be enough fuel for breeder re-actors to satisfy our energy needs for 5 billion years at1983’s total energy consumption rate, thus making nu-clear energy effectively a renewable energy.[9][10]

Nuclear waste became a greater concern by the 1990s. Inbroad terms, spent nuclear fuel has twomain components.The first consists of fission products, the leftover frag-ments of fuel atoms after they have been split to releaseenergy. Fission products come in dozens of elements andhundreds of isotopes, all of them lighter than uranium.The second main component of spent fuel is transuranics(atoms heavier than uranium), which are generated fromuranium or heavier atoms in the fuel when they absorbneutrons but do not undergo fission. All transuranic iso-topes fall within the actinide series on the periodic table,and so they are frequently referred to as the actinides.The physical behavior of the fission products is markedlydifferent from that of the transuranics. In particular,fission products do not themselves undergo fission, andtherefore cannot be used for nuclear weapons. Further-more, only seven long-lived fission product isotopes havehalf-lives longer than a hundred years, which makes theirgeological storage or disposal less problematic than fortransuranic materials.[11]

With increased concerns about nuclear waste, breedingfuel cycles became interesting again because they can re-duce actinide wastes, particularly plutonium and minoractinides.[12] Breeder reactors are designed to fission theactinide wastes as fuel, and thus convert them to morefission products.After "spent nuclear fuel" is removed from a light waterreactor, it undergoes a complex decay profile as each nu-clide decays at a different rate. Due to a physical oddityreferenced below, there is a large gap in the decay half-lives of fission products compared to transuranic isotopes.If the transuranics are left in the spent fuel, after 1,000to 100,000 years, the slow decay of these transuranicswould generatemost of the radioactivity in that spent fuel.Thus, removing the transuranics from the waste elimi-nates much of the long-term radioactivity of spent nuclearfuel.[13]

Today’s commercial light water reactors do breed somenew fissile material, mostly in the form of plutonium. Be-cause commercial reactors were never designed as breed-ers, they do not convert enough uranium-238 into pluto-nium to replace the uranium-235 consumed. Nonethe-less, at least one-third of the power produced by com-mercial nuclear reactors comes from fission of plutonium

1

2 3 TYPES OF BREEDER REACTOR

generated within the fuel.[14] Even with this level of plu-tonium consumption, light water reactors consume onlypart of the plutonium and minor actinides they produce,and nonfissile isotopes of plutonium build up, along withsignificant quantities of other minor actinides.[15] Evenwith reprocessing, reactor-grade plutonium is normallyrecycled only once in LWRs as mixed oxide fuel, withlimited reductions in long-term waste radioactivity.

2 Conversion ratio, breakeven,breeding ratio, doubling time,and burnup

One measure of a reactor’s performance is the “conver-sion ratio” (the average number of new fissile atoms cre-ated per fission event). All proposed nuclear reactors ex-cept specially designed and operated actinide burners[16]experience some degree of conversion. As long as thereis any amount of a fertile material within the neutron fluxof the reactor, some new fissile material is always created.The ratio of new fissile material in spent fuel to fissilematerial consumed from the fresh fuel is known as the“conversion ratio” or “breeding ratio” of a reactor.For example, commonly used light water reactors have aconversion ratio of approximately 0.6. Pressurized heavywater reactors (PHWR) running on natural uranium havea conversion ratio of 0.8.[17] In a breeder reactor, the con-version ratio is higher than 1. “Breakeven” is achievedwhen the conversion ratio becomes 1: the reactor pro-duces as much fissile material as it uses.“Doubling time” is the amount of time it would take fora breeder reactor to produce enough new fissile materialto create a starting fuel load for another nuclear reac-tor. This was considered an importantmeasure of breederperformance in early years, when uranium was thought tobe scarce. However, since uranium ismore abundant thanthought, and given the amount of plutonium available inspent reactor fuel, doubling time has become a less im-portant metric in modern breeder reactor design.[18][19]

"Burnup" is a measure of how much energy has been ex-tracted from a given mass of heavy metal in fuel, oftenexpressed (for power reactors) in terms of gigawatt-daysper ton of heavy metal. Burnup is an important factorin determining the types and abundances of isotopes pro-duced by a fission reactor. Breeder reactors, by design,have extremely high burnup compared to a conventionalreactor, as breeder reactors produce much more of theirwaste in the form of fission products, while most or all ofthe actinides are meant to be fissioned and destroyed.[20]

In the past breeder reactor development focused onreactors with low breeding ratios, from 1.01 for theShippingport Reactor[21][22] running on thorium fuel andcooled by conventional light water to over 1.2 for the Rus-sian BN-350 liquid-metal-cooled reactor.[23] Theoreti-

cal models of breeders with liquid sodium coolant flow-ing through tubes inside fuel elements (“tube-in-shell”construction) suggest breeding ratios of at least 1.8 arepossible.[24]

3 Types of breeder reactor

fissile fission%

fertile capture%

less fertile

shortlived α% β%

α

96%

α

2%

α

15%

238U

238Pu

240Pu

244Cm

239Pu

241Pu

242mAm

243Cm

245Cm

242Pu

241Am

243Am

243Pu

242Am

244Am

242Cm

9%

4%

64%

72%

84%

85% 85%

10% 1%

1%

91%

36%

25%

79% 1%

10%16% 99%

3% 13% 81%

β3%

β

β81%

EC17%

β

Production of heavy transuranic actinides in current thermal-neutron fission reactors through neutron capture and decays.Starting at Uranium-238, isotopes of Plutonium, Americium, andCurium are all produced. In a Fast Neutron Breeder Reactor, allthese isotopes may be burned as fuel.

Many types of breeder reactor are possible:A 'breeder' is simply a reactor designed for very high neu-tron economy with an associated conversion rate higherthan 1.0. In principle, almost any reactor design couldpossibly be tweaked to become a breeder. An exampleof this process is the evolution of the Light Water Re-actor, a very heavily moderated thermal design, into theSuper Fast Reactor [25] concept, using light water in anextremely low-density supercritical form to increase theneutron economy high enough to allow breeding.Aside from water cooled, there are many other types ofbreeder reactor currently envisioned as possible. Theseinclude molten-salt cooled, gas cooled, and liquid metalcooled designs in many variations. Almost any of thesebasic design types may be fueled by uranium, plutonium,many minor actinides, or thorium, and they may be de-signed for many different goals, such as creating more fis-sile fuel, long-term steady-state operation, or active burn-ing of nuclear wastes.For convenience, it is perhaps simplest to divide the extantreactor designs into two broad categories based upon theirneutron spectrum, which has the natural effect of dividingthe reactor designs into those which are designed to utilizeprimarily uranium and transuranics, and those designed to

3

use thorium and avoid transuranics.

• Fast breeder reactor or FBR uses fast (unmoder-ated) neutrons to breed fissile plutonium and pos-sibly higher transuranics from fertile uranium-238.The fast spectrum is flexible enough that it can alsobreed fissile uranium-233 from thorium, if desired.

• Thermal breeder reactor use thermal spectrum(moderated) neutrons to breed fissile uranium-233from thorium (thorium fuel cycle). Due to thebehavior of the various nuclear fuels, a thermalbreeder is thought commercially feasible only withthorium fuel, which avoids the buildup of the heav-ier transuranics.

4 Reprocessing

Fission of the nuclear fuel in any reactor producesneutron-absorbing fission products. Because of this un-avoidable physical process, it is necessary to reprocess thefertile material from a breeder reactor to remove thoseneutron poisons. This step is required if one is to fullyutilize the ability to breed as much or more fuel than isconsumed. All reprocessing can present a proliferationconcern, since it extracts weapons usable material fromspent fuel.[26] The most common reprocessing technique,PUREX, presents a particular concern, since it was ex-pressly designed to separate pure plutonium. Early pro-posals for the breeder reactor fuel cycle posed an evengreater proliferation concern because they would usePUREX to separate plutonium in a highly attractive iso-topic form for use in nuclear weapons.[27][28]

Several countries are developing reprocessing meth-ods that do not separate the plutonium from theother actinides. For instance, the non-water basedpyrometallurgical electrowinning process, when used toreprocess fuel from an integral fast reactor, leaves largeamounts of radioactive actinides in the reactor fuel.[8]More conventional advanced reprocessing systems whichare based on water, like PUREX, include SANEX,UNEX, DIAMEX, COEX, and TRUEX, as well as pro-posals to combine PUREX with co-processes. All ofthese systems have better proliferation resistance thanPUREX, although their adoption rate is low.[29][30]

In the thorium cycle, thorium-232 breeds by convertingfirst to protactinium-233, which then decays to uranium-233. If the protactinium remains in the reactor, smallamounts of U-232 are also produced, which has thestrong gamma emitter Tl-208 in its decay chain. Similarto uranium-fueled designs, the longer the fuel and fertilematerial remain in the reactor, the more of these undesir-able elements build up. Inside the envisioned commercialthorium reactors high levels of U232 would be allowed toaccumulate, leading to extremely high gamma radiationdoses from any uranium derived from thorium. These

gamma rays complicate the safe handling of a weaponand the design of its electronics; this explains why U-233 has never been pursued for weapons beyond proof-of-concept demonstrations.[31]

5 Waste reduction

Nuclear waste became a greater concern by the 1990s.Breeding fuel cycles attracted renewed interest becauseof their potential to reduce actinide wastes, particularlyplutonium and minor actinides.[12] Since breeder reactorson a closed fuel cycle would use nearly all of the actinidesfed into them as fuel, their fuel requirements would bereduced by a factor of about 100. The volume of wastethey generate would be reduced by a factor of about 100as well. While there is a huge reduction in the volume ofwaste from a breeder reactor, the activity of the waste isabout the same as that produced by a light water reactor.In addition, the waste from a breeder reactor has a dif-ferent decay behavior, because it is made up of differentmaterials. Breeder reactor waste is mostly fission prod-ucts, while light water reactor waste has a large quantityof transuranics. After spent nuclear fuel has been re-moved from a light water reactor for longer than 100,000years, these transuranics would be the main source of ra-dioactivity. Eliminating them would eliminate much ofthe long-term radioactivity from the spent fuel.[13]

In principle, breeder fuel cycles can recycle and con-sume all actinides,[9] leaving only fission products. Asthe graphic in this section indicates, fission products havea peculiar 'gap' in their aggregate half-lives, such thatno fission products have a half-life longer than 91 yearsand shorter than two hundred thousand years. As a re-sult of this physical oddity, after several hundred yearsin storage, the activity of the radioactive waste froma Fast Breeder Reactor would quickly drop to the lowlevel of the long-lived fission products. However, to ob-tain this benefit requires the highly efficient separationof transuranics from spent fuel. If the fuel reprocessingmethods used leave a large fraction of the transuranics inthe final waste stream, this advantage would be greatlyreduced.[8]

Both types of breeding cycles can reduce actinide wastes:

• The fast breeder reactor's fast neutrons can fissionactinide nuclei with even numbers of both protonsand neutrons. Such nucleii usually lack the low-speed "thermal neutron" resonances of fissile fuelsused in LWRs.[37]

• The thorium fuel cycle inherently produces lowerlevels of heavy actinides. The fertile material inthe thorium fuel cycle has an atomic weight of 232,while the fertile material in the uranium fuel cyclehas an atomic weight of 238. That mass differencemeans that thorium-232 requires six more neutron

4 6 BREEDER REACTOR CONCEPTS

capture events per nucleus before the transuranic el-ements can be produced. In addition to this simplemass difference, the reactor gets two chances to fis-sion the nuclei as the mass increases: First as the ef-fective fuel nuclei U233, and as it absorbs two moreneutrons, again as the fuel nuclei U235.[38][39]

A reactor whose main purpose is to destroy actinides,rather than increasing fissile fuel stocks, is sometimesknown as a burner reactor. Both breeding and burn-ing depend on good neutron economy, and many designscan do either. Breeding designs surround the core by abreeding blanket of fertile material. Waste burners sur-round the core with non-fertile wastes to be destroyed.Some designs add neutron reflectors or absorbers.[16]

6 Breeder reactor concepts

There are several concepts for breeder reactors; the twomain ones are:

• Reactors with a fast neutron spectrum are calledfast breeder reactors (FBR) – these typically utilizeuranium-238 as fuel.

• Reactors with a thermal neutron spectrum are calledthermal breeder reactors – these typically utilizethorium-232 as fuel.

6.1 Fast breeder reactor

Controlrods

FissileCore

BreederBlanket

BiologicalShielding

Liquidmetalcoolant

Heatexchanger

Steamgenerator

Heatexchanger

Steamgenerator

FissileCore

BreederBlanket

BiologicalShielding

Liquidmetalcoolant

ReactorPool Pump

CoolantLevel

FlowBaffle

ControlRods Steam

Water

Power-generation

loop

Intermediateloop

Intermediateloop

Reactorpool

(primary coolant)

Reactorloop

(primary coolant)

Liquid Metal cooled Fast Breeder Reactors (LMFBR)

"Pool" Design "Loop" Design

(to power turbine)

(from power turbine)

Schematic diagram showing the difference between the Loop andPool types of LMFBR.

In 2006 all large-scale fast breeder reactor (FBR)power stations were liquid metal fast breeder reactors(LMFBR) cooled by liquid sodium. These have been ofone of two designs:[1]

• Loop type, in which the primary coolant is circu-lated through primary heat exchangers outside thereactor tank (but inside the biological shield due toradioactive sodium-24 in the primary coolant)

• Pool type, in which the primary heat exchangers andpumps are immersed in the reactor tank

Experimental Breeder Reactor II, which served as the prototypefor the Integral Fast Reactor

All current fast neutron reactor designs use liquid metalas the primary coolant, to transfer heat from the coreto steam used to power the electricity generating tur-bines. FBRs have been built cooled by liquid metals otherthan sodium—some early FBRs used mercury, other ex-perimental reactors have used a sodium-potassium alloycalled NaK. Both have the advantage that they are liquidsat room temperature, which is convenient for experimen-tal rigs but less important for pilot or full scale power sta-tions. Lead and lead-bismuth alloy have also been used.The relative merits of lead vs sodium are discussed here.Looking further ahead, four of the proposed generationIV reactor types are FBRs:[40]

• Gas-Cooled Fast Reactor (GFR) cooled byhelium.

• Sodium-Cooled Fast Reactor (SFR) based on theexisting Liquid Metal FBR (LMFBR) and IntegralFast Reactor designs.

• Lead-Cooled Fast Reactor (LFR) based on Sovietnaval propulsion units.

• Supercritical Water Reactor (SCWR) based onexisting LWR and supercritical boiler technology.

FBRs usually use a mixed oxide fuel core of up to 20%plutonium dioxide (PuO2) and at least 80% uraniumdioxide (UO2). Another fuel option is metal alloys, typi-cally a blend of uranium, plutonium, and zirconium (usedbecause it is “transparent” to neutrons). Enriched ura-nium can also be used on its own.In many designs, the core is surrounded in a blanket oftubes containing non-fissile uranium-238 which, by cap-turing fast neutrons from the reaction in the core, is con-verted to fissile plutonium-239 (as is some of the uraniumin the core), which is then reprocessed and used as nuclearfuel. Other FBR designs rely on the geometry of the fuelitself (which also contains uranium-238), arranged to at-tain sufficient fast neutron capture. The plutonium-239

6.1 Fast breeder reactor 5

(or the fissile uranium-235) fission cross-section is muchsmaller in a fast spectrum than in a thermal spectrum, asis the ratio between the 239Pu/235U fission cross-sectionand the 238U absorption cross-section. This increases theconcentration of 239Pu/235U needed to sustain a chainreaction, as well as the ratio of breeding to fission.[16]

On the other hand, a fast reactor needs no moderator toslow down the neutrons at all, taking advantage of the fastneutrons producing a greater number of neutrons per fis-sion than slow neutrons. For this reason ordinary liquidwater, being a moderator as well as a neutron absorber, isan undesirable primary coolant for fast reactors. Becauselarge amounts of water in the core are required to coolthe reactor, the yield of neutrons and therefore breed-ing of 239Pu are strongly affected. Theoretical work hasbeen done on reduced moderation water reactors, whichmay have a sufficiently fast spectrum to provide a breed-ing ratio slightly over 1. This would likely result in anunacceptable power derating and high costs in an liquid-water-cooled reactor, but the supercritical water coolantof the SCWR has sufficient heat capacity to allow ad-equate cooling with less water, making a fast-spectrumwater-cooled reactor a practical possibility.[25]

The only commercially operating reactor to date (2015) isthe BN-600 reactor in Russia, a 560MW sodium cooledreactor.

6.1.1 Integral fast reactor

One design of fast neutron reactor, specifically designedto address the waste disposal and plutonium issues, wasthe integral fast reactor (also known as an integral fastbreeder reactor, although the original reactor was de-signed to not breed a net surplus of fissile material).[41][42]

To solve the waste disposal problem, the IFR had an on-site electrowinning fuel reprocessing unit that recycledthe uranium and all the transuranics (not just plutonium)via electroplating, leaving just short half-life fission prod-ucts in the waste. Some of these fission products couldlater be separated for industrial or medical uses and therest sent to a waste repository (where they would not haveto be stored for anywhere near as long as wastes con-taining long half-life transuranics). The IFR pyropro-cessing system uses molten cadmium cathodes and elec-trorefiners to reprocess metallic fuel directly on-site atthe reactor.[43] Such systems not only commingle all theminor actinides with both uranium and plutonium, theyare compact and self-contained, so that no plutonium-containing material ever needs to be transported awayfrom the site of the breeder reactor. Breeder reactorsincorporating such technology would most likely be de-signed with breeding ratios very close to 1.00, so thatafter an initial loading of enriched uranium and/or plu-tonium fuel, the reactor would then be refueled only withsmall deliveries of natural uranium metal. A quantity ofnatural uranium metal equivalent to a block about the

size of a milk crate delivered once per month wouldbe all the fuel such a 1 gigawatt reactor would need.[44]Such self-contained breeders are currently envisioned asthe final self-contained and self-supporting ultimate goalof nuclear reactor designers.[8][16] The project was can-celed in 1994 by United States Secretary of Energy HazelO'Leary.[45][46]

6.1.2 Other fast reactors

The graphite core of the Molten Salt Reactor Experiment

Another proposed fast reactor is a fast molten salt reac-tor, in which the molten salt’s moderating properties areinsignificant. This is typically achieved by replacing thelight metal fluorides (e.g. LiF, BeF2) in the salt carrierwith heavier metal chlorides (e.g., KCl, RbCl, ZrCl4).Several prototype FBRs have been built, ranging in elec-trical output from a few light bulbs’ equivalent (EBR-I,1951) to over 1,000 MWe. As of 2006, the technol-ogy is not economically competitive to thermal reactortechnology—but India, Japan, China, South Korea andRussia are all committing substantial research funds tofurther development of Fast Breeder reactors, anticipat-ing that rising uranium prices will change this in the longterm. Germany, in contrast, abandoned the technologydue to safety concerns. The SNR-300 fast breeder reac-tor was finished after 19 years despite cost overruns sum-ming up to a total of 3.6 billion Euros, only to then beabandoned.[47]

As well as their thermal breeder program, India is alsodeveloping FBR technology, using both uranium and tho-rium feedstocks.

6 7 BREEDER REACTOR CONTROVERSY

6.2 Thermal breeder reactor

The Shippingport Reactor, used as a prototype Light WaterBreeder for five years beginning in August, 1977

The advanced heavy water reactor (AHWR) is one of thefew proposed large-scale uses of thorium.[48] India is de-veloping this technology, their interest motivated by sub-stantial thorium reserves; almost a third of the world’sthorium reserves are in India, which also lacks significanturanium reserves.The third and final core of the Shippingport AtomicPower Station 60 MWe reactor was a light water thoriumbreeder, which began operating in 1977.[49] It used pel-lets made of thorium dioxide and uranium-233 oxide; ini-tially, the U-233 content of the pellets was 5–6% in theseed region, 1.5–3% in the blanket region and none inthe reflector region. It operated at 236 MWt, generating60 MWe and ultimately produced over 2.1 billion kilo-watt hours of electricity. After five years, the core wasremoved and found to contain nearly 1.4% more fissilematerial than when it was installed, demonstrating thatbreeding from thorium had occurred.[50][51]

The liquid fluoride thorium reactor (LFTR) is alsoplanned as a thorium thermal breeder. Liquid-fluoridereactors may have attractive features, such as inherentsafety, no need to manufacture fuel rods and possiblysimpler reprocessing of the liquid fuel. This conceptwas first investigated at the Oak Ridge National Lab-oratory Molten-Salt Reactor Experiment in the 1960s.From 2012 it became the subject of renewed interestworldwide.[52] Japan, China, the UK, as well as privateUS, Czech and Australian companies have expressed in-tent to develop and commercialize the technology.

7 Breeder reactor controversy

Like many aspects of nuclear power, fast breeder re-actors have been subject to much controversy over theyears. In 2010 the International Panel on Fissile Ma-terials said “After six decades and the expenditure of

the equivalent of tens of billions of dollars, the promiseof breeder reactors remains largely unfulfilled and ef-forts to commercialize them have been steadily cut backin most countries”. In Germany, the United King-dom, and the United States, breeder reactor develop-ment programs have been abandoned.[53][54] The ratio-nale for pursuing breeder reactors—sometimes explicitand sometimes implicit—was based on the following keyassumptions:[54][55]

• It was expected that uranium would be scarce andhigh-grade deposits would quickly become depletedif fission power were deployed on a large scale; thereality, however, is that since the end of the cold war,uranium has been much cheaper and more abundantthan early designers expected.[56]

• It was expected that breeder reactors would quicklybecome economically competitive with the light-water reactors that dominate nuclear power today,but the reality is that capital costs are at least 25%more than water cooled reactors.

• It was thought that Breeder reactors could be as safeand reliable as light-water reactors, but safety issuesare cited as a concern with fast reactors that use asodium coolant, where a leak could lead to a sodiumfire.

• It was expected that the proliferation risks posed bybreeders and their “closed” fuel cycle, in which plu-tonium would be recycled, could be managed. Butsince plutonium breeding reactors produce pluto-nium from U238, and thorium reactors produce fis-sile U233 from thorium, all breeding cycles couldtheoretically pose proliferation risks.[57]

These problems have stymied their deployment and lentcredence to calls for their abandonment.There are some past anti-nuclear advocates that have be-come pro-nuclear power as a clean source of electricitysince breeder reactors effectively recycle most of theirwaste. This solves one of the most important negativeissues of nuclear power. In the documentary "Pandora’sPromise", a case is made for breeder reactors becausethey provide a real, high kW alternative to fossil fuel en-ergy. According to the movie, one pound of uranium pro-vides as much power as 5000 barrels of oil.[58]

FBRs have been built and operated in the United States,theUnitedKingdom, France, the formerUSSR, India andJapan.[1] An experimental FBR in Germany was built butnever operated. As of 2014 one such reactor was beingused for power generation, with another scheduled forearly 2015. Several reactors are planned, many for re-search related to the Generation IV reactor initiative.

7

8 Breeder reactor development andnotable breeder reactors

The Soviet Union (comprising Russia and other countries,dissolved in 1991) constructed a series of fast reactors,the first being mercury-cooled and fueled with plutoniummetal, and the later plants sodium-cooled and fueled withplutonium oxide.BR-1 (1955) was 100W (thermal) was followed by BR-2at 100 kW and then the 5MW BR-5.BOR-60 (first criticality 1969) was 60 MW, with con-struction started in 1965.[62]

9 Future plants

In 2012 an FBR called the Prototype Fast Breeder Re-actor was under construction in India, due to be com-pleted that year, with commissioning date known by mid-year.[63][64] The FBR program of India includes the con-cept of using fertile thorium-232 to breed fissile uranium-233. India is also pursuing the thorium thermal breederreactor. A thermal breeder is not possible with purelyuranium/plutonium based technology. Thorium fuel isthe strategic direction of the power program of India, ow-ing to the nation’s large reserves of thorium, but world-wide known reserves of thorium are also some four timesthose of uranium. India’s Department of Atomic Energy(DAE) said in 2007 that it would simultaneously constructfour more breeder reactors of 500 MWe each includingtwo at Kalpakkam.[65]

The Chinese Experimental Fast Reactor is a 65MW (thermal), 20MW (electric), sodium-cooled, pool-type reactor with a 30-yeardesign lifetime and a target burnup of 100 MWd/kg.

The China Experimental Fast Reactor (CEFR) is a 25MW(e) prototype for the planned China Prototype FastReactor (CFRP).[66] It started generating power on 21July 2011.[67]

China also initiated a research and development project inthorium molten-salt thermal breeder reactor technology(Liquid fluoride thorium reactor), formally announced at

the Chinese Academy of Sciences (CAS) annual confer-ence in January 2011. Its ultimate target is to investigateand develop a thorium-based molten salt nuclear systemover about 20 years.[68][69]

Kirk Sorensen, former NASA scientist and Chief Nu-clear Technologist at Teledyne Brown Engineering, haslong been a promoter of thorium fuel cycle and particu-larly liquid fluoride thorium reactors. In 2011, Sorensenfounded Flibe Energy, a company aimed to develop20-50 MW LFTR reactor designs to power militarybases.[70][71][72][73]

South Korea is developing a design for a standardizedmodular FBR for export, to complement the standard-ized PWR (PressurizedWater Reactor) and CANDU de-signs they have already developed and built, but has notyet committed to building a prototype.

A cutaway model of the BN-600 reactor, superseded by the BN-800 reactor family.

Russia has a plan for increasing its fleet of fast breederreactors significantly. A BN-800 reactor (800 MWe) atBeloyarsk was completed in 2012, succeeding a smallerBN-600. In June 2014 the BN-800 was started in theminimum power mode.[74] It is expected to start to workin nominal power mode later in 2015.[75]

Plans for the construction of an even larger BN-1200reactor (1,200 MWe) initially anticipated completion in2018, with two additional BN-1200 reactors built by theend of 2030.[76] However, in 2015 Rosenergoatom post-poned construction indefinitely to allow fuel design to beimproved after more experience of operating the BN-800reactor, and amongst cost concerns.[75]

An experimental lead-cooled fast reactor, BREST-300will be built at the Siberian Chemical Combine (SCC) inSeversk. The BREST design is seen as a successor to theBN series and the 300 MWe unit at the SCC could be theforerunner to a 1,200 MWe version for wide deploymentas a commercial power generation unit. The developmentprogram is as part of an Advanced Nuclear TechnologiesFederal Program 2010-2020 that seeks to exploit fast re-actors as a way to be vastly more efficient in the use ofuranium while 'burning' radioactive substances that oth-erwise would have to be disposed of as waste. BREST

8 11 REFERENCES

refers to bystry reaktor so svintsovym teplonositelem, Rus-sian for 'fast reactor with lead coolant'. Its core wouldmeasure about 2.3 metres in diameter by 1.1 metres inheight and contain 16 tonnes of fuel. The unit would berefuelled every year, with each fuel element spending fiveyears in total within the core. Lead coolant temperaturewould be around 540 °C, giving a high efficiency of 43%,primary heat production of 700 MWt yielding electricalpower of 300 MWe. The operational lifespan of the unitcould be 60 years. The design is expected to be completedby NIKIET in 2014 for construction between 2016 and2020.[77]

Construction of the BN-800 reactor

On February 16, 2006, the U.S., France and Japan signedan “arrangement” to research and develop sodium-cooledfast reactors in support of the Global Nuclear EnergyPartnership.[78] In April 2007 the Japanese governmentselected Mitsubishi Heavy Industries as the “core com-pany in FBR development in Japan”. Shortly there-after, MHI started a new company, Mitsubishi FBRSystems (MFBR) to develop and eventually sell FBRtechnology.[79]

The Marcoule Nuclear Site in France, location of the Phénix (onthe left) and possible future site of the ASTRID Gen-IV reactor.

In September 2010 the French government allocated651.6 million euros to the Commissariat à l'énergie atom-ique to finalize the design of “Astrid” (Advanced SodiumTechnological Reactor for Industrial Demonstration), a600 MW reactor design of the 4th generation to be op-erational in 2020.[80][81] As of 2013 the UK had showninterest in the PRISM reactor and was working in con-cert with France to develop ASTRID.In October 2010 GE Hitachi Nuclear Energy signed amemorandum of understanding with the operators ofthe US Department of Energy’s Savannah River site,which should allow the construction of a demonstrationplant based on the company’s S-PRISM fast breeder re-

actor prior to the design receiving full NRC licensingapproval.[82] In October 2011 The Independent reportedthat the UKNuclear Decommissioning Authority (NDA)and senior advisers within the Department for Energy andClimate Change (DECC) had asked for technical and fi-nancial details of the PRISM, partly as a means of reduc-ing the country’s plutonium stockpile.[83]

The traveling wave reactor proposed in a patent byIntellectual Ventures is a fast breeder reactor designed tonot need fuel reprocessing during the decades-long life-time of the reactor. The breed-burn wave in the TWRdesign does not move from one end of the reactor to theother but gradually from the inside out. Moreover, asthe fuel’s composition changes through nuclear transmu-tation, fuel rods are continually reshuffled within the coreto optimize the neutron flux and fuel usage at any givenpoint in time. Thus, instead of letting the wave propa-gate through the fuel, the fuel itself is moved through alargely stationary burn wave. This is contrary to manymedia reports, which have popularized the concept as acandle-like reactor with a burn region that moves downa stick of fuel. By replacing a static core configura-tion with an actively managed “standing wave” or “soli-ton” core, TerraPower's design avoids the problem ofcooling a highly variable burn region. Under this sce-nario, the reconfiguration of fuel rods is accomplishedremotely by robotic devices; the containment vessel re-mains closed during the procedure, and there is no asso-ciated downtime.[84]

10 See also• India’s three stage nuclear power programme

• Fast neutron reactor

• Sodium-cooled fast reactor

• Integral Fast Reactor

• Lead-cooled fast reactor

• Gas-cooled fast reactor

• Generation IV reactor

• Reduced moderation water reactor

• Supercritical water reactor

• Nuclear fusion-fission hybrid

• David Hahn

11 References[1] Waltar, A.E.; Reynolds, A.B (1981). Fast breeder reac-

tors. New York: Pergamon Press. p. 853. ISBN 978-0-08-025983-3.

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[2] Helmreich, J.E. Gathering Rare Ores: The Diplomacy ofUranium Acquisition, 1943–1954, Princeton UP, 1986:ch. 10 ISBN 0-7837-9349-9

[3] http://www.world-nuclear.org/info/Current-and-Future-Generation/Fast-Neutron-Reactors/

[4] http://gsdm.u-tokyo.ac.jp/file/140528gps_chang.pdf

[5] http://www.laradioactivite.com/en/site/pages/FastNeutrons.htm

[6] http://www.laradioactivite.com/en/site/pages/Neutrons_Capture.htm

[7] http://atom.kaeri.re.kr/ton/nuc11.html

[8] “Pyroprocessing Technologies: RECYCLING USEDNUCLEAR FUEL FOR A SUSTAINABLE ENERGYFUTURE” (PDF). Argonne National Laboratory. Re-trieved 25 December 2012.

[9] "www.ne.anl.gov/pdfs/12_Pyroprocessing_bro_5_12_v14%5B6%5D.pdf" (PDF). Argonne NationalLaboratory. Retrieved 25 December 2012.

[10] Weinberg, A. M., and R. P. Hammond (1970). “Limits tothe use of energy,” Am. Sci. 58, 412.

[11] “Radioactive Waste Management”. World Nuclear Asso-ciation.

[12] “Supply of Uranium”. World Nuclear Association. Re-trieved 11 March 2012.

[13] Bodansky, David (January 2006). “The Status of NuclearWaste Disposal”. Physics and Society (American PhysicalSociety) 35 (1).

[14] “Information Paper 15”. World Nuclear Association. Re-trieved 15 December 2012.

[15] U. Mertyurek; M. W. Francis; I. C. Gauld. “SCALE 5Analysis of BWR Spent Nuclear Fuel Isotopic Compo-sitions for Safety Studies” (PDF). ORNL/TM-2010/286.OAK RIDGE NATIONAL LABORATORY. Retrieved25 December 2012.

[16] E. A. Hoffman; W.S. Yang; R.N. Hill. “Preliminary CoreDesign Studies for the Advanced Burner Reactor over aWide Range of Conversion Ratios”. Argonne NationalLaboratory. ANL-AFCI-177.

[17] Kadak, Prof. Andrew C. “Lecture 4, Fuel Deple-tion & Related Effects”. Operational Reactor Safety22.091/22.903. Hemisphere, as referenced by MIT. p.Table 6–1, “Average Conversion or Breeding Ratios forReference Reactor Systems”. Retrieved 24 December2012.

[18] Rodriguez, Placid; Lee, S. M. “Who is afraid of breed-ers?". Indira Gandhi Centre for Atomic Research,Kalpakkam 603 102, India. Retrieved 24 December2012.

[19] R. Prasad (10 October 2002). “Fast breeder reactor: Isadvanced fuel necessary?". Chennai, India: The Hindu :Online edition of India’s National Newspaper.

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[21] Adams, R. (1995). Light Water Breeder Reactor, AtomicEnergy Insights 1.

[22] Kasten, P.R. (1998) Review of the Radkowsky ThoriumReactor Concept. (PDF) Science & Global Security 7,237–269.

[23] Fast Breeder Reactors, Department of Physics & Astron-omy, Georgia State University. Retrieved 16 October2007.

[24] Hiraoka, T., Sako, K., Takano, H., Ishii, T. and Sato, M.(1991). A high-breeding fast reactor with fission productgas purge/tube-in-shell metallic fuel assemblies. NuclearTechnology 93, 305–329.

[25] T. Nakatsuka et al. Current Status of Research and Devel-opment of Supercritical Water-Cooled Fast Reactor (SuperFast Reactor) in Japan. Presented at IAEA Technical Com-mittee Meeting on SCWRs in Pisa, 5–8 July 2010.

[26] R. Bari et al. (2009). “Proliferation Risk Reduction StudyofAlternative Spent Fuel Processing” (PDF). BNL-90264-2009-CP. Brookhaven National Laboratory. Retrieved 16December 2012.

[27] C.G. Bathke et al. (2008). “An Assessment of the Prolif-eration Resistance of Materials in Advanced Fuel Cycles”(PDF). Department of Energy. Retrieved 16 December2012.

[28] “An Assessment of the Proliferation Resistance of Ma-terials in Advanced Nuclear Fuel Cycles” (PDF). 2008.Retrieved 16 December 2012.

[29] Ozawa, M.; Sano, Y.; Nomura, K.; Koma, Y.; Takanashi,M. “A New Reprocessing System Composed of PUREXand TRUEX Processes For Total Separation of Long-lived Radionuclides” (PDF).

[30] Simpson, Michael F.; Law, Jack D. (February 2010).“Nuclear Fuel Reprocessing” (PDF). Idaho National Lab-oratory.

[31] Kang and Von Hippel (2001). “U-232 and theProliferation-Resistance of U-233 in Spent Fuel” (PDF).0892-9882/01. Science & Global Security, Volume 9 pp1-32. Retrieved 18 December 2012.

[32] Plus radium (element 88). While actually a sub-actinide, itimmediately precedes actinium (89) and follows a three-element gap of instability after polonium (84) where noisotopes have half-lives of at least four years (the longest-lived isotope in the gap is radon-222 with a half life of lessthan four days). Radium’s longest lived isotope, at 1600years, thus merits the element’s inclusion here.

[33] Specifically from thermal neutron fission of U-235, e.g. ina typical nuclear reactor.

[34] Milsted, J.; Friedman, A. M.; Stevens, C. M. (1965).“The alpha half-life of berkelium-247; a new long-livedisomer of berkelium-248”. Nuclear Physics 71 (2): 299.doi:10.1016/0029-5582(65)90719-4.“The isotopic analyses disclosed a species of mass 248 in

10 11 REFERENCES

constant abundance in three samples analysed over a pe-riod of about 10 months. This was ascribed to an isomerof Bk248 with a half-life greater than 9 y. No growth ofCf248 was detected, and a lower limit for the β− half-lifecan be set at about 104 y. No alpha activity attributableto the new isomer has been detected; the alpha half-life isprobably greater than 300 y.”

[35] This is the heaviest isotope with a half-life of at least fouryears before the "Sea of Instability".

[36] Excluding those "classically stable" isotopes with half-lives significantly in excess of 232Th, e.g. while 113mCdhas a half-life of only fourteen years, that of 113Cd isnearly eight quadrillion.

[37] “Neutron Cross Sections4.7.2”. National Physical Labo-ratory. Retrieved 17 December 2012.

[38] David, Sylvain; Elisabeth Huffer; Hervé Nifenecker.“Revisiting the thorium-uranium nuclear fuel cycle”(PDF). europhysicsnews.

[39] “Fissionable Isotopes”.

[40] US DOE Nuclear Energy Research Advisory Committee(2002). “A Technology Roadmap for Generation IV Nu-clear Energy Systems” (PDF). GIF-002-00.

[41] “The Integral Fast Reactor”. Reactors Designed by Ar-gonne National Laboratory. Argonne National Labora-tory. Retrieved 2013-05-20.

[42] “National Policy Analysis #378: Integral Fast Reactors:Source of Safe, Abundant, Non-Polluting Power - Decem-ber 2001”.

[43] Hannum, W.H., Marsh, G.E. and Stanford, G.S. (2004).PUREX and PYRO are not the same. Physics and Soci-ety, July 2004.

[44] University of Washington (2004). Energy Numbers: En-ergy in natural processes and human consumption, somenumbers. Retrieved 16 October 2007.

[45] Kirsch, Steve. “The Integral Fast Reactor (IFR) project:Congress Q&A”.

[46] Stanford, George S. “Comments on the Misguided Termi-nation of the IFR Project” (PDF).

[47] Werner Meyer-Larsen: Der Koloß von Kalkar. DerSpiegel 43/1981 vom 19.10.1981, S. 42-55. “Der Koloßvon Kalkar”, Der Spiegel, 16 July Error in template * un-known parameter name (Template:Der Spiegel): '1; Text'(German)

[48] “Thorium”.

[49] "files.asme.org/ASMEORG/Communities/History/Landmarks/5643.pdf" (PDF).

[50] "atomicinsights.com/1995/10/light-water-breeder-reactor-adapting-proven-system.html".

[51] Thorium information from theWorld Nuclear Association

[52] Stenger, Victor (12 January 2012). “LFTR: A Long-TermEnergy Solution?". Huffington Post.

[53] M.V. Ramana; Mycle Schneider (May–June 2010). “It’stime to give up on breeder reactors” (PDF). Bulletin of theAtomic Scientists.

[54] Frank von Hippel et al. (February 2010). Fast Breeder Re-actor Programs: History and Status (PDF). InternationalPanel on Fissile Materials. ISBN 978-0-9819275-6-5.Retrieved 28 April 2014.

[55] M.V. Ramana; Mycle Schneider (May–June 2010). “It’stime to give up on breeder reactors” (PDF). Bulletin of theAtomic Scientists.

[56] “Global Uranium Supply and Demand - Council on For-eign Relations”.

[57] “Global Uranium Supply and Demand - Council on For-eign Relations”.

[58] Len Koch, pioneering nuclear engineer (2013). [ andPandora’s Promise] (DVD, STREAMING) (Motion pic-ture). Impact Partners and CNN Films. 11 minutes in.Retrieved 24 Apr 2014. One pound of uranium, whichis the size of my fingertip, if you could release all of theenergy, has the equivalent of about 5,000 barrels of oil.

[59] S. R. Pillai, M. V. Ramana (2014). “Breeder reac-tors: A possible connection between metal corrosion andsodium leaks”. Bulletin of the Atomic Scientists 70 (3).doi:10.1177/0096340214531178. Retrieved 15 February2015.

[60] “Database on Nuclear Power Reactors”. PRIS. IAEA. Re-trieved 15 February 2015.

[61] http://cheekatales.weebly.com/experimental-breeder-reactor-1-ebr-1.html

[62] FSUE “State Scientific Center of Russian Federation Re-search Institute of Atomic Reactors”. “Experimental fastreactor BOR-60”. Retrieved 15 June 2012.

[63] Srikanth (27 November 2011). “80% of work on fastbreeder reactor at Kalpakkam over”. Kalpakkam: TheHindu. Retrieved 25 March 2012.

[64] Jaganathan, Venkatachari (11 May 2011). “India’s newfast-breeder on track, nuclear power from Septembernext”. Chennai: Hindustan Times. Retrieved 25 March2012.

[65] “Home – India Defence”.

[66] “IAEA Fast Reactor Database” (PDF).

[67] “China’s experimental fast neutron reactor begins generat-ing power”. xinhuanet. July 2011. Retrieved 2011-07-21.

[68] Qimin, Xu (26 January 2011). “The future of nuclearpower plant safety “are not picky eaters"" (in Chinese).Retrieved 30 October 2011. Yesterday, as the ChineseAcademy of Sciences of the first to start one of the strate-gic leader in science and technology projects, “the fu-ture of advanced nuclear fission energy - nuclear energy,

11

thorium-based molten salt reactor system” project was of-ficially launched. The scientific goal is 20 years or so, de-veloped a new generation of nuclear energy systems, allthe technical level reached in the test and have all the in-tellectual property rights.

[69] Clark, Duncan (16 February 2011). “China enters raceto develop nuclear energy from thorium”. EnvironmentBlog (London: The Guardian (UK)). Retrieved 30 Octo-ber 2011.

[70] “Flibe Energy”.

[71] “Kirk Sorensen has started a Thorium Power companyFlibe Energy”. The Next Bi Future. 23 May 2011. Re-trieved 30 October 2011.

[72] “Live chat: nuclear thorium technologist Kirk Sorensen”.Environment Blog (London: The Guardian (UK)). 7September 2001. Retrieved 30 October 2011.

[73] Martin, William T. (27 September 2011). “NewHuntsville company to build thorium-based nuclear reac-tors”. Huntsville Newswire. Retrieved 30 October 2011.

[74] "Белоярская АЭС: начался выход БН−800 наминимальный уровень мощности". AtomInfo.ru.Retrieved 27 July 2014.

[75] “Russia postpones BN-1200 in order to improve fuel de-sign”. World Nuclear News. 16 April 2015. Retrieved 19April 2015.

[76] "До 2030 в России намечено строительство трёхэнергоблоков с реакторами БН−1200”. AtomInfo.ru.Retrieved 27 July 2014.

[77] “Fast moves for nuclear development in Siberia”. WorldNuclear Association. Retrieved 8 October 2012.

[78] “Department of Energy - Generation IV International Fo-rum Signs Agreement to Collaborate on Sodium CooledFast Reactors”.

[79] “Nuclear Engineering International”.

[80] World Nuclear News (16 September 2010). “French gov-ernment puts up funds for Astrid”. Retrieved 15 June2012.

[81] “Quatrième génération : vers un nucléaire durable” (PDF)(in French). CEA. Retrieved 15 June 2012.

[82] “Prototype Prism proposed for Savannah River”. WorldNuclear News. 28 October 2010. Retrieved 2010-11-04.

[83] Connor, Steve (28 October 2011). “New life for old ideathat could dissolve our nuclear waste”. The Independent(London). Retrieved 2011-10-30.

[84] “TR10: Traveling Wave Reactor”. Technology Review.March 2009. Retrieved 2009-03-06.

12 External links• Breeder terminology

• US Nuclear Program

• IAEA Fast Reactors Database

• IAEA Technical Documents on Fast Reactors

• Reactors Designed by Argonne National Labora-tory: Fast Reactor Technology Argonne pioneeredthe development of fast reactors and is a leader in thedevelopment of fast reactors worldwide. See alsoArgonne’s Nuclear Science and Technology Legacy.

• Atomic Heritage Foundation - EBR-I

• The Changing Need for a Breeder Reactor byRichard Wilson at The Uranium Institute 24th An-nual Symposium, September 1999

• Experimental Breeder Reactor-II (EBR-II): An In-tegrated Experimental Fast Reactor Nuclear PowerStation

• International Thorium Energy Organisation - www.IThEO.org

12 13 TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES

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