Development of Novel Neutron Shielding Concrete

Neutron shielding is very important for neutron facility construction. Concrete is usually used for neutron shielding. Although concrete is inexpensive, massive thickness is required. In the present work, a novel neutron shielding concrete using colemanite rock and peridotite rock was developed. Its shielding performance was evaluated through the transmission experiments by using ²⁵²Cf spontaneous fission source and the calculations with the MCNP5 code. The results show that a neutron 1/100 attenuation length of the neutron concrete shield with a typical colemanite content of 10 wt% is shorter by a factor of 1.7 than that of normal concrete. The results show that the shielding performance becomes better when the thickness is still thicker and the incident neutron spectrum is softer.

The colemanite-peridotite concrete (neutron shielding concrete) was applied to biological shields of the Versatile High Intensity Total Diffractometer on the Japan Proton Accelerator Research Complex. Using this concrete permitted a reduction in the thickness of the shielding wall by a maximum of 25 cm compared to the normal concrete and a reduction of the iron in the beam dump.