SHIELD THAT IS DIFFICULT TO ACTIVATE AND METHOD FOR CONSTRUCTING THIS SHIELD

PROBLEM TO BE SOLVED: To make it difficult to activate a shield even if it receives neutrons and high-energy particles by using an aluminum implanted dam plate as a reinforcing material and short and small pieces of lead as a coarse aggregate for concrete. SOLUTION: At the outset, a pedestal 20 on which a radiation generator is loaded is made on a foundation base 18. Then, an aluminum implanted dam plate 12 is assembled in a position where the outside of a shield is covered. Subsequently, short and small pieces 14 of lead as a coarse aggregate are poured into a space zoned by the dam plate 12 and the inside of the space is covered with the coarse aggregate while tamping it. Afterward, filling mortar 16 is poured and sufficiently hardened. It is preferable that a material of the implanted dam plate 12 is aluminum or aluminum alloy. As to the size of short and small pieces 14 of lead, those of 20 to 100 mm are used and the combination of large and small ones in diameter is also effective. Moreover, a material containing a low content of elements that cause nuclear reaction with neutrons and the like is preferable as a coarse aggregate to be added to the mortar 16.