Shielding analysis of nuclear data measurement facility using EGS4 and MCNP4 codes

The electron accelerator facility generating high-energy particle for nuclear data measurements has a probability of radiation emission at all times, and thus, the shielding analysis for the facility should be performed. In this work, two Monte Carlo codes, EGS4 and MCNP4B, were employed for the accurate calculations of radiation source term and ambient dose at the working areas. EGS4 code was used in the calculation of neutron and photon sources from the accelerator beam line and the beam target. The ambient dose at the working areas was calculated by MCNP4B code using neutron and photon source terms calculated from the EGS4 runs. The results showed that the ambient dose at the working areas was much higher than the design limit of Pohang Accelerator Laboratory, 5 μSv/hr, and thus, it is recommended that the additional effective shields, lead shield of 14 cm thick at the LINAC room and 11 cm thick at the target room, should to be installed for ensuring radiation safety of the nuclear data measurement facility. (author)