Dual fluid reactor

The dual fluid reactor (DFR) is a reactor concept of a private German research institute, the Institute for Solid-State Nuclear Physics. Combining the advantages of the molten salt reactor with those of the liquid metal cooled reactor, it is supposed to reach the criteria for reactors of the Generation IV International Forum. The fuel is a molten solution of actinide chloride salts, while the cooling is provided by molten lead in a separate loop. As a fast breeder reactor, the DFR can use both natural uranium and thorium to breed fissile material, as well as recycle High-level waste and plutonium. Due to the high thermal conductivity of the molten metal, the DFR is an inherently safe reactor (the decay heat can be removed passively).

If the reactor works as intended, the U-238 of a spent nuclear fuel element of a LWR (about 1 ton) could be completely dissolved in Cl-salt, including the problematic long-living transuranic parts. Complete breeding and fission could power a 1 GW thermal DFR for about 2.5 years. After that time the element would be completely converted into fission products and the need for storage in a final deposition for nuclear waste would be reduced from 1 million to about 300 years.

The reactor design won the public vote for the Galileo Knowledge Prize in the German GreenTec Awards of 2013, but the award committee presiding over the awards changed the rules to exclude all nuclear designs before announcing the winner. The DFR participants successfully sued in response to this.[1][2][3][4]

A conceptual predecessor of the DFR was the UK 1970s lead-cooled fast spectrum MSR (MSFR), which was undergoing a design path inclusive of the fissile fuel likewise dissolved in a molten chloride salt, with experimental work undertaken over 1968-73. Funding ceased in 1974.[5]