Radiation shield unit, method of manufacturing radiation shield unit, and radiation shield structure

A method of manufacturing a radiation shield unit configured to shield against neutron rays, X-rays, and γ-rays, the method comprising:

• mixing cement, a first aggregate, a second aggregate, and water, the first aggregate having an average particle size of less than 5 mm, an average length of less than 5 mm, or an average thickness of less than 5 mm, the first aggregate containing a first gadolinium compound, the second aggregate having an average particle size of 5 mm or more, an average length of 5 mm or more, or an average thickness of 5 mm or more, and the second aggregate containing a second gadolinium compound, wherein
• a volume ratio of the fine aggregate to the cement is 2 or more and 3 or less,
• a volume ratio of the coarse aggregate to the cement is 4 or more and 6 or less, and
• a volume ratio of the water to the cement is 0.5 or more and 0.6 or less.