Abstract: By executing an additional link process, unresolved external reference information of object modules of new-version subroutines is resolved based on external reference information which is resolved when load modules are created, and a reference table for storing entry points of old-version subroutines and new-version subroutines and an additional load module are created. When an additional load process is executed, the additional load module and reference table dynamically loaded into a memory and a machine instruction of the entry points of the old-version subroutines is rewritten as a trap instruction. If the load module including the old-version subroutines are being executed, the execution of the load modules is continued by calling a control continuation process. When the old-version subroutines are called after the new-version subroutines are loaded in the memory, the new-version subroutines are called by executing a control transfer process.

Abstract: A fast reactor comprises a core composed of nuclear fuel, a core barrel surrounding an outer periphery of the core, an annular reflector surrounding an outer periphery of the core barrel, a partition wall structure surrounding an outer periphery of the annular reflector and supporting the core barrel by a supporting structure arranged radially of the fast reactor, the partition wall structure constituting an inner wall of a coolant passage for a primary coolant, a neutron shield surrounding an outer periphery of the partition wall structure and disposed in the coolant passage, a reactor vessel surrounding an outer periphery of the neutron shield and having an inner wall constituting an outer wall of the coolant passage, and a guard vessel surrounding an outer periphery of the reactor vessel.