Fuel assembly and core of fast reactor

A fuel assembly in which a nuclear fuel material region in which a nuclear fuel material is present is formed, and a first lower core fuel region, a first inner blanket region, and a first upper core fuel region are formed in the nuclear fuel material region in this order from a lower end to an upper end of the nuclear fuel material region, the fuel assembly comprising:

• a plurality of first fuel rods in which the nuclear fuel material is present;
• and
• a plurality of second fuel rods in which the nuclear fuel material is present, wherein
• in each of the first fuel rods, a second lower core fuel region is formed at a position corresponding to the first lower core fuel region, a second inner blanket region is formed at a position corresponding to the first inner blanket region, and a second upper core fuel region is formed at a position corresponding to the first upper core fuel region,
• in each of the second fuel rods, a third lower core fuel region is formed at a position corresponding to the first lower core fuel region, a third inner blanket region is formed at a position corresponding to the first inner blanket region, and a third upper core fuel region is formed at a position corresponding to the first upper core fuel region, and
• the nuclear fuel material present in the second inner blanket region of the first fuel rod does not contain minor actinide and contains uranium, and the nuclear fuel material present in the third inner blanket region of the second fuel rod does not contain uranium and contains minor actinide.