JP2901462B

PURPOSE:To shorten the work schedule while enhancing the work efficiency in the installation of steel structure of lower dry well Within a reactor container. CONSTITUTION:A main beam 2 for upper floor, a main beam 3 for lower floor having an outer diameter smaller than the inner peripheral diameter of a ring 6 for reinforcing the foundation of reactor body, steel structural members including columns 4 and small beams 5, a heat-exchanger 11, and pipings 12, 13 for control rod and instrumentation are assembled integrally on the outside of the foundation 1 for reactor body. The assembly is then suspended in the foundation 1 having inner peripheral surface secured with the reinforcing ring 6. The main beam 2 for upper floor is temporarily set on the reinforcing ring 6 and then the main beam 2 is shifted horizontally thus setting the installing position of the main beam 3 for lower floor coupled with the main beam 2 for upper floor through columns. Thereafter, the steel structural members are set and the machines are installed along with the pipings thereof.