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What is a Lead-cooled Fast Reactor?
A Lead-cooled Fast Reactor (LFR) is a versatile fast neutron reactor that can use depleted uranium, thorium, or burn waste actinide products from light water reactor (LWR) fuel. An LFR employs liquid metal cooling, operating at atmospheric pressure through natural convection. The envisioned unit sizes vary, from small factory-built “battery” units for small grids to larger modular 300-400 MWe units and 1400 MWe single plants. A relatively high operating temperature of 550°C is typically achievable, with advanced materials allowing for 800°C, enabling thermochemical hydrogen production.
Fast Neutrons
A lead-cooled fast reactor (LFR) uses the fast neutron spectrum – neutrons with an average energy in excess of 1 MeV. Therefore, no moderator is required.
Molten Metal Coolant
Commonly, a lead-cooled fast reactor uses liquid lead metal (or lead-based alloys) as a coolant because of its great thermal properties, low reactivity with many other chemicals and low neutron absorption cross-section.
Fertile Fuel
In a lead-cooled fast reactors, it is common to use a mixed fuel such as uranium-plutonium nitride.
This is facilitated by the use of the fast neutron spectrum enabling use of fertile fuels, based upon isotopes such as thorium-232 , uranium-234 or uranium-238 which can each adsorb a fast neutron and convert into the fissile isotopes uranium-233, uranium-235 and plutonium-239.
Development of Lead-cooled Fast Reactor Technology
History of the Lead-cooled Fast Reactor
Initial development of lead-cooled fast reactor designs focused on experimental designs and prototypes like the US STAR and Japan’s LSPR, both using lead or lead-bismuth cooling. A lead-cooled fast reactor shares many design characteristics with other designs based upon molten metal cooling, such as a sodium-cooled fast reactor.
What is happening today?
In 2014, key developments included Russia’s SVBR-100 and BREST-300, Europe’s ALFRED, and Belgium’s MYRRHA. Russia’s SVBR-100 has been cancelled, and Westinghouse proposed an LFR project to the DOE in 2015 for demonstration by 2035.
The SSTAR reactor, running at 564°C, features an integral steam generator and operates for 20 years before the entire unit is returned for fuel recycling. The ELFR project, led by Ansaldo Nuclear, was designed for 600 MWe but appears to be superseded by the ALFRED reactor, which runs on MOX fuel at 480°C.
Explore Further
Choose from the articles below to continue learning about nuclear.
Gas-Cooled Fast Reactor (GFR) – High-Efficiency, Next-Gen Nuclear Power
Supercritical Water Reactor (SCWR) – Steam, Speed and Sustainability
High Temperature Gas Reactor (HTGR) – Innovation in Prisms & Pebbles
Sodium-cooled Fast Reactor (SFR) – a Fast Future for Fission?
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