PURPOSE: To effectively use the inside of a fuel storage pool by forming such structure as to install a blade guide at the shelf part of the fuel storage pool.

CONSTITUTION: A fuel storage pool shelf 1 is provided with a supporting base 2, and this supporting base 2 is formed of a seat plate 2a and a lower supporting plate 2d provided at the seat plate 2a through frame plates 2c. The whole weight of a blade guide 4 is loaded on the supporting base 2. The lower supporting plate 2d has a seat hole 2e for supporting the lower plug 4a of the blade guide 4 in the fit-in state. An oscillation preventing part is provided to prevent the upper part of the blade guide 4, and this oscillation preventing part has a contact plate 6 and an upper supporting plate 8 projecting horizontally from the contact plate 6. The contact plate 6 is fixed to the side wall surface of the fuel storage pool. The upper supporting plate 8 supports the upper end part of the blade guide 4 and becomes a guide between the channels 4b of the blade guide 4 at the blade guide storage time by a fuel grip means.