Breeding ratio is about 1. It is to have active and passive shutdown systems and passive decay heat removal. However, in October an agreement was signed with Russia's Atomstroyexport to start pre-project and design works for a commercial nuclear power plant with two BN reactors in China, referred to by CIAE as 'project 2' CDFR, with construction to start in and commissioning In contrast to the intention in Russia, these would use ceramic MOX fuel pellets. The project was expected to lead to bilateral cooperation of fuel cycles for fast reactors, but is apparently suspended.
Some of these features may be in the CFR See fuller description below. Qixing I is a fast sub-critical accelerator-driven system — ADS used for transmutation research related to wastes, Qixing II is a lead-cooled zero-power fast reactor.
Closely related to its major research initiative on an advanced spent fuel conditioning process ACP , and designed to be fuelled by the product of it, KAERI has proposed development of a pool-type sodium-cooled fast reactor, which will operate in burner not breeder mode. ACP will use electrometallurgical pyroprocessing to close the fuel cycle with oxide fuels which have been reduced to the metal on a commercial basis.
The pulverised used fuel is heated to drive off volatile fission products and then it is reduced to metal. In a bath of molten lithium and potassium chloride, uranium is recovered electrolytically.
This is intrinsically proliferation-resistant because it is so hot radiologically, and the curium provides a high level of spontaneous neutrons. The primary goal of PGSFR is to demonstrate the reduction of radioactive waste from spent conventional reactor fuel by transmuting radiotoxic and long-lived elements.
They demonstrated the safe shutdown and cooling of the reactor without operator action following a simulated loss-of-cooling accident… The PGSFR is the world's first fast reactor that exploits inherent safety characteristics to prevent severe accidents. It has evolved from a MWe version. It has a transmuter core consisting of uranium and transuranics in metal form from pyro-processing, and no breeding blanket is involved.
It is working on lead-bismuth-cooled designs of 35, and MW which would operate on pyro-processed fuel. The 35 MW unit is designed to be leased for 20 years and operated without refuelling, and then returned to the supplier. It would be refuelled at the pyro-processing plant and have a design life of 60 years. In the USA, five fast neutron reactors have operated, and several more designed.
The experimental breeder reactor EBR-1 at Idaho was designed to validate the physics of breeding fuel. Incidentally, in it produced enough power to run its own building — a milestone achievement. By the reactor had fulfilled its main experimental purposes, and was tested further by restricting coolant flow, which caused a core melt. The reactor was rebuilt with a new, slightly different core and ran to the end of It was declared a National Historical Landmark in The idea was to demonstrate a complete sodium-cooled breeder reactor power plant with onsite reprocessing of metallic fuel, and this was successfully done in The emphasis then shifted to testing materials and fuels metal and ceramic oxides, carbides and nitrides of uranium and plutonium for larger fast reactors.
Finally it became the IFR prototype, using metallic alloy U-Pu-Zr fuels, and it pioneered the closed fuel cycle, which involved remote handling at all stages through fuel fabrication. All the time, it generated some 1 TWh of power as well. The reactor could be operated as a breeder or not.
All these were demonstrated, though the program was aborted in before the recycle of neptunium and americium was properly evaluated. In the first, the main primary cooling pumps were shut off with the reactor at full power.
Without allowing the normal shutdown systems to interfere, the reactor power dropped to near zero within about five minutes. No damage to the fuel or the reactor resulted. The second test was again with the reactor at full power, and the flow in the secondary cooling system was stopped. This caused the reactor temperature to increase, and as the fuel, primary sodium coolant and structure expanded, the reactor shut down on its own. A further political goal was demonstrating a proliferation-resistant closed fuel cycle, with plutonium being recycled with other actinides.
The IFR ranked first in their study which was released in April The first US commercial FBR was Fermi 1 in Michigan, but it operated for only three years before a coolant problem caused overheating and it was shut down with some damage to the fuel. After repair it was restarted in , but its licence was not renewed in Its cooling system did not enable it to operate at or near full power of 60 MWe net.
It was the only fast reactor to use a full core of Pu-U mixed oxide fuel, and was sodium-cooled. It completed its safety test program in , demonstrating the capability of the Doppler coefficient re core thermal expansion in a mixed oxide reactor to stabilise it and control accidents in oxide-fueled, sodium-cooled fast reactors.
Fuel and coolant were removed in and the University of Arkansas bought it in It was closed down at the end of , and since it has been deactivated under care and maintenance pending possible decommissioning. However, in August the Department of Energy indicated that it could possibly be recommissioned as part of the Global Nuclear Energy Partnership demonstration process.
Core height was 1. Refuelling interval 20 months, for fuel life 60 months. No US fast neutron reactor has so far been larger than 66 MWe and none has supplied electricity commercially. An intermediate sodium loop takes heat to the steam generators.
The pool-type modules below ground level contain the complete primary system with sodium coolant. All transuranic elements are removed together in the electrometallurgical reprocessing so that fresh fuel has minor actinides with the plutonium and uranium. The reactor is designed to use a heterogeneous metal alloy core with fuel assemblies in two fuel zones. Breeding ratio depends on purpose and hence configuration, so ranges from 0.
The commercial-scale plant concept, part of an 'Advanced Recycling Center', uses three power blocks six reactor modules to provide MWe. See also section on Electrometallurgical 'pyroprocessing' in the information page on Processing of Used Nuclear Fuel.
The whole stockpile could be irradiated thus in five years, with some by-product electricity but frequent interruptions for fuel changing and the plant would then proceed to re-use it for about 55 years solely for MWe of electricity generation, with one third of the fuel being changed every two years. For this UK version, the breeding ratio is 0.
The cost of the plant would be comparable to a large conventional reactor, according to GEH, which is starting to develop a supply chain in the UK to support the proposal. No reprocessing plant Advanced Recycling Centre is envisaged initially, but this could be added later. Initial deployment is envisaged in Canada, and will seek a preliminary regulatory review with the CNSC through its vendor design review process.
This is based on a PRISM reactor of MWe and uses molten salt to store heat so that the output could be increased to about MWe for up to five hours for load-following. Also in October Bechtel joined the consortium to provide design, licensing, procurement and construction services to the project. It will be factory-produced, with components readily assembled onsite, and with 'walk-away' passive safety.
Installation would be below ground level. The ARC system comprises a uranium alloy metal core as a cartridge submerged in sodium at ambient pressure in a stainless steel tank. It would have a refuelling interval of 20 years for cartridge changeover.
Initial fuel will be low-enriched uranium Reprocessing its used fuel will not separate plutonium. ARC has load-following capability. It has several passive safety features and in particular the fuel, fuel rod cladding, and reactor core and core structures are manufactured from GA's proprietary SiGA silicon-carbide composite, a high-tech ceramic matrix composite that can withstand more than twice the temperatures of the metal components used in most reactors.
Decay heat removal is entirely passive. EM 2 would also be suitable for process heat applications. The main pressure vessel can be trucked or railed to the site, and installed below ground level, and the high-speed gas turbine generator is also truck-transportable. The company expects a four-unit EM 2 plant to be built in 42 months. It will be dry-cooled regarding waste heat, with passive safety.
It will be factory-built and assembled onsite. A demonstration unit is expected to operate in the early s. The core is in a metal-filled module sitting in a large pool of secondary molten metal coolant which also accommodates the separate and unconnected steam generators. After this the module is removed, stored onsite until the primary lead or Pb-Bi coolant solidifies, and it would then be shipped as a self-contained and shielded item. A new fuelled module would be supplied complete with primary coolant.
The ENHS is designed for developing countries but is not yet close to commercialisation. It is a fast neutron modular reactor cooled by lead-bismuth eutectic, with passive safety features. Its MWt size means it can be shipped by rail and cooled by natural circulation. It uses U-transuranic nitride fuel in a 2. Decay heat removal is by external air circulation. Any commercial electricity generation then would be by fuel cells, from the hydrogen.
Its development is further off. After a year life without refuelling, the whole reactor unit is then returned for recycling the fuel.
The core is one metre diameter and 0. A prototype was envisaged by For all STAR concepts, regional fuel cycle support centres would handle fuel supply and reprocessing, and fresh fuel would be spiked with fission products to deter misuse. Complete burnup of uranium and transuranics is envisaged in STAR-H2, with only fission products being waste.
The Westinghouse-led project team includes US national laboratories, universities and the private sector. The company said that it believed an LFR plant will be the next advanced reactor technology to be deployed. Beyond electricity generation, applications would include hydrogen production and water desalination.
This has been considered in the past as generically, a candle reactor, or breed-burn reactor, since it is designed to burn slowly from one end of a core to the other, making the actual fuel as it goes. The reactor would use natural or depleted uranium packed inside hundreds of hexagonal pillars. The reaction requires a small amount of enriched uranium to get started and could run for decades without refueling. However it is a low-density core and needs to be relatively large — one report talks about a cylinder 3m wide and 4m long.
In this was boldly selected by MIT Technology Review as one of ten emerging technologies of note. Eventual sizes could range from a few hundred MWe to over MWe. However, by mid TerraPower changed the design to be a standing wave reactor , since too many neutrons would be lost behind the travelling wave of the previous design and it would not be practical to remove the heat efficiently — the cooling system could not follow the wave.
As the wave would be surrounded by new fuel in most directions, more neutrons would be utilized compared with a traveling wave scheme. It would still use sodium as coolant. Terrapower said a MWe demonstration plant — TWR-P — was planned for construction followed by operation of larger commercial plants of about MWe from the late s. However, development was paused when the US government ruled against working with China on advanced reactor concepts.
Nuclear is very, very safe today, but we believe this design will make it dramatically safer. It relies on natural laws of physics to mitigate accident scenarios like the one at Fukushima. It efficiently uses an inexpensive fuel source. It reduces the need for enrichment and chemical reprocessing and simplifies the fuel cycle.
These use a fluid in numerous sealed horizontal steel heatpipes to passively conduct heat from the hot fuel core where the fluid vapourises to the external condenser where the fluid releases latent heat of vapourisation with heat exchanger. There is a large negative temperature reactivity coefficient.
There is very little decay heat after shutdown. Experimental work on heatpipe reactors for space has been with very small units about kWe , using sodium as the fluid. The number 1. Only 1 neutron is needed for the fission chain reaction to be stable, so the remaining 1. The amount of time for a breeder to produce enough material to fuel a second reactor is called its doubling time. Fossil Fuels. Nuclear Fuels.
Acid Rain. Climate Change. Climate Feedback. Ocean Acidification. Rising Sea Level. Although the U does most of the fissioning, more than 90 percent of the atoms in the fuel are U --potential neutron capture targets and future plutonium atoms. Pu , which is created when U captures a neutron, forms U and then undergoes two beta decays, happens to be even better at fissioning than U Pu is formed in every reactor and also fissions as the reactor operates.
In fact, a nuclear reactor can derive a significant amount of energy from such plutonium fission. But because this plutonium fissions, it reduces the amount that is left in the fuel.
To maximize plutonium production, therefore, a reactor must create as much plutonium as possible while minimizing the amount that splits. This is why many breeder reactors are also fast reactors. Fast neutrons are ideal for plutonium production because they are easily absorbed by U to create Pu , and they cause less fission than thermal neutrons.
Some fast breeder reactors can generate up to 30 percent more fuel than they use. Creating extra fuel in nuclear reactors, however, is not without its concerns: One is that the plutonium produced can be removed and used in nuclear weapons. Another is that, to extract the plutonium, the fuel must be reprocessed, creating radioactive waste and potentially high radiation exposures. For these reasons, in the U. This is the main reason why thermal reactors were developed first.
Time scales in fast reactors are typically faster than those in thermal reactors mostly because there are fewer delayed neutrons in fast reactors. Thus they can go through unpredicted changes faster than thermal reactors. Bubbles in fast reactor coolant can cause the reactor to heat up rather than cool down, as in a traditional reactor.
Higher heat makes more bubbles, which make more heat, and so on. This positive feedback is scary but manageable, thanks to overpowering negative feedbacks.
To keep the neutrons moving quickly, fast reactors require exotic coolants derived from heavy atoms. The most common coolant is liquid sodium, which is well known but highly reactive with air and water. These bizarre materials require extra care and lower tolerance in many systems such as piping , possibly bringing costs up. From the beginning of nuclear power, we knew the benefits of fast reactors.
Uranium was thought to be a very scarce resource, so breeder reactors were considered essential. Enrico Fermi postulated the possibility of breeding, and this possibility was confirmed in the EBR-1 reactor in Idaho which, incidentally was also the first reactor to produce electricity. Several other fast test reactors were built around the world in France, the UK, Japan, Russia, India, China and today, the world has achieved around reactor-years of operation with fast reactors.
Note: We have an elaborate reactor development history page that covers this topic in general. Uranium was found to be plentiful, and the commercial nuclear industry favored the already-developed and operating thermal reactors. Also, recycling nuclear fuel as is often but not always called for in fast reactor fuel cycles brings up proliferation concerns that inspired the Jimmy Carter administration to cancel a large US effort to develop a fast-reactor system.
Nowadays, with talk of expanding the share of nuclear power in the electricity-producing world, debate about the remaining amount of uranium on earth has resurfaced. Why switch from coal to uranium if we might run out in a few centuries anyway? Also, one of the only ways to really destroy nuclear waste is to burn it in fast reactors. So, by providing good responses to the sustainability and the waste toxicity, fast reactors have maintained the interest of much of the forward-looking nuclear crowd.
It might be wise to go read our moderation page for a second and come back when you understand that neutrons emerge from fission reactions at high speeds and that we typically like to slow them down to thermal energies in order to increase their chances of continuing the chain reaction. This is what is done in thermal reactors.
Splitting atoms is not the only thing neutrons do. In nuclides such as Uranium, thermal neutrons are readily absorbed without causing a fission — resulting in what we call a capture.
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