Development and Performance of Metal Fuel Elements for Fast Breeder Reactors

A US perspective on fast reactor fuel fabrication technology and experience part I: metal fuels and assembly design

“…Early fast reactors in the US were fueled with metal fuel, including the Experimental Breeder Reactors, EBR-I (1951EBR-I ( -1963 and EBR-II (1965, in Idaho [9][10][11]. Metal fuels used in EBR-I consisted of unalloyed U and U-Zr and Pu-Al alloys, a summary of which is provided in Table 1.…”

“…U-Zr binary alloys and U-Pu-Zr ternary alloys were also later used as driver fuel or proposed for driver fuel use and irradiated in EBR-II [11,[18][19][20] and FFTF [21]. Alloying the metal fuel, which was often performed using Zr, was highly desirable because this raised the alloy solidus temperature, enhanced dimensional stability under irradiation, and reduced fuel cladding chemical interaction [22,23].…”

Fuels for sodium-cooled fast reactors: US perspective

“…1 at.% of burnup corresponds to roughly 9.4 GWd/ MTHM Exposure When applied to in-core components and materials of construction this term refers to a duration and intensity of in-service use. Can be expressed in units of neutron fluence (n/cm 2 ), usually for neutrons of energy greater than 0.1 MeV (E > 0.1 MeV); units of proportional incident neutron or fission fragment collision (displacements per atom, or dpa), which incorporates neutron spectrum to reflect degree of radiation damage; or units of simple time of exposure, such as effective full-power days (EFPD) Fuel or Cladding Breach production reactors operated at Hanford, the Experimental Breeder Reactor (EBR, later renamed the Experimental Breeder Reactor I, or EBR-I) in Idaho, and the Dounreay Fast Reactor (DFR) in the UK [19,21,22]. The reasons for its selection included ease of fabrication, high-thermal conductivity and high-fissile and -fertile densities (which allowed higher breeding ratios and smaller core sizes for specific reactor power).…”

“…The cladding alloy was later changed from Type 304L stainless to Type 316 stainless steel, due to the improved swelling resistance of Type 316 stainless steel [16], and because fuel/cladding interdiffusion (which effectively reduces the load-bearing thickness of the cladding wall) was significantly reduced with Type 316 stainless steel [11,19]. The Mark-II fuel design proved to be capable of reliable operation to 10 at.% burnup [11,22].…”

“…Of the several alloying elements being considered for addition to the uranium-plutonium binary alloy to raise the solidus temperature, Zr seemed promising due to its reduction of fuel/cladding interdiffusion and favorable early irradiation testing results [20,22].…”