The Blanket Comparison and Selection Study (BCSS) was a 2-yr, multilaboratory project initiated by the U.S. Department of Energy/Office of Fusion Energy. Its primary objectives were to (a) define a limited number of blanket concepts that should provide the focus of the blanket research and development (R&D) program, and (b) identify and prioritize critical issues for the leading blanket concepts. The BCSS focused on the mainline approach for fusion reactor development, namely, the D-T-Li fuel cycle, tokamaks and tandem mirror reactors (TMRs) for electrical energy production, and a reactor parameter space that is generally considered achievable with modest extrapolations from the current data base. The STARFIRE and Mirror Advanced Reactor Study reactor and plant designs, with a nominal first-wall neutron load of 5 MW/m2, were used as reference designs for the study. The study focused on

  1. development of reference design guidelines, evaluation criteria, and a methodology for evaluating and ranking candidate blanket concepts
  2. compilation of the required data base and development of a uniform systems analysis for comparison
  3. development of conceptual designs for the comparative evaluation
  4. evaluation of leading concepts for engineering feasibility, economic performance, and safety
  5. identification and prioritization of R&D requirements for the leading blanket concepts.
Sixteen concepts (nine TMR and seven tokamak) that were identified as leading candidates in the early phases of the study were evaluated in detail. The overall evaluation concluded that the following concepts should provide the focus for the blanket R&D program (breeder/coolant/structure):
  1. lithium/lithium/vanadium alloy
  2. Li2O/helium/ferritic steel
  3. LiPb alloy/LiPb alloy/vanadium alloy
  4. lithium/helium/ferritic steel.