AbstractThe paper proposes that a low aspect ratio tokamak can be a driver of a subcritical blanket to breed fissile material and transmute high level waste (HLW). The transmutation and energy amplifying principle are described. Multifunctional blanket analysis shows that this kind of reactor offers possibilities to breed fissile material, transmute HLW, and produce high energy amplification as well. After 30 years operation, this type of reactor can transmute all the HLW initially loaded and the BHP level is greatly decreased. By comparison with other transmutation devices, this type of reactor has many advantages and should receive more attention.