  Laboratories and Universities regularly apply for approval from the United
States Nuclear Regulatory Commission (NRC) to use neutron generators for
experimental research. To comply with the regulations set by the NRC, adequate
shielding is necessary to ensure that the radiation dose rates experienced by
an operator, and outside the walls of any containment buildings, are below the
prescribed levels. Typically, the neutron source needs to be shielded such that
the radiation dose rate experienced by any user is less than 0.25 mRem/hr
(500mrem/2000-hour work-year). To address this requirement, we investigate the
effectiveness of boronated concrete, boronated water, and light water shielding
materials and their applicability to three neutron sources. We present our
findings on the radiation shielding design and calculations for three neutron
sources situated inside shielding layers. Our modeling utilized the Monte Carlo
n-Particle transport codes (MCNP6.2) to simulate neutron attenuation of the
shielding. The simulation results reveal that a light water shielding can
sufficiently reduce the dose rate for an individual located as close as two
meters from the source. Therefore, this shield design can effectively decrease
the radiation dose below the maximum recommended limit.
