Concept evaluation of a nuclear design for electronuclear fuel production: evaluation of ORNL's proposed TMF--ENFP

The use of an external neutron source, generated via an accelerator, represents a potential means for producing the fissile isotopes 233U and 239Pu. One promising accelerator-breeder concept employs a sodium-cooled ternary metal fertile blanket (239Pu, 238U, and 232Th) surrounding a central column of sodium. A preliminary assessment of the neutronic characteristics and the relevant economic parameters for this system, designated the TMF--ENFP (Ternary Metal Fueled ElectroNuclear Fuel Producer) is described here. The rationale for selecting the particular configuration utilized was addressed from the standpoints of fissile production, heat generation, and target interaction. The basic assumption assumed a 300-mA beam of 1-GeV protons from the accelerator. A calculational model of the target blanket assembly was developed which met certain prespecified design limitations. A preliminary assessment of the nuclear performance, thermal-hydraulic, and economic parameters was made. For the latter, the use of the TMF--ENFP in conjunction with the denatured (233U/238U) fuel cycle in both PWRs and CANDUs was considered. The basic accelerator-driven blanket concept requires a tradeoff between fissile production and the heat-removal capability. Moreover, the centrally located proton beam results in a significant gradient in the power density (Peak/Average approx. 2). Fissile production of the TMF--ENFP configuration considered was 5.8 kg/day of 233U. Such a production rate would support a maximum of 5.58 GW(e) of denatured PWR capacity [or alternatively 11.58 GW(e) of denatured CANDU capacity]. The cost of the TMF--ENFP/thermal reactor system is judged to be competitive with current--generation LEU--PWRs operating from a > $80/lb U3O8 resource base