FUEL ASSEMBLY STRUCTURE FOR FAST REACTOR AND FURNACE CORE LOADED WITH THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a fuel assembly structure for a fast reactor capable of preventing a block of a coolant flow due to a void generated at the time of a transitional phenomenon such as a loss of a coolant flow amount or the like, and capable of preventing the reduction of the thermal margin of a fuel pin at the time of normal operation.SOLUTION: A plurality of fuel pins 17 which encapsulates a fissile material as a fuel is bundled up and stored inside a wrapper tube 12. The fuel pin 17 encapsulates a plurality of fuel pellets inside a cladding tube made of a stainless steel and forms a space in an upper end part of a fuel region 18 to be defined as a gas plenum region 16. An opening 13 including the lower end of the gas plenum region 16 and extending to the upper part thereof is provided on a side wall of the wrapper tube 12, thereby forming a fuel assembly 1. With the opening 13 formed so as not to overlap the fuel region 18, the upper part portion of the fuel region 18 where the cladding tube temperature of the fuel pin 17 is the highest can be cooled by the coolant.