FUEL ASSEMBLY AND UNCLEAR REACTOR CORE

摘要

PROBLEM TO BE SOLVED: To provide a fuel assembly having a large thermal margin and allowing improvement of a critical power of fuel. SOLUTION: This fuel assembly has plural fuel rods 2 arranged in plural lines and plural rows and having lower end parts held by a lower tie plate; and a channel box 7 formed so as to surrounds the fuel rods 2, holding the fuel rods 2. A structure material (a partition member) 33 for plurally partitioning the inside of the channel box 7 in a horizontal cross section is provided inside the channel box 7. An interval C2 between a wall face of the partition member 33 and the fuel rods 2 facing the partition member 33 is set to a smaller value than an interval C1 between the inner wall face of the channel box 7 and the fuel rods 2 facing the channel box 7.