| The Neutron Radiography Reactor (NRAD) at the Idaho National Laboratory (INL) has two beamlines extending out of the east and north faces of the reactor core. The control rod withdrawal procedure has been altered recently, potentially changing the physics of the neutron beams, requiring re-characterization. The characterization of the East Radiography Station (ERS) involved experiments used to measure the following characteristics: Neutron flux, neutron flux profile, cadmium ratio, image quality and the neutron energy spectrum. The thermal neutron flux was measured using gold foil activation and determined to be 9.61 x 106 ± 2.47 x 105 n/cm2-s with a relatively uniform profile across the image plane. The cadmium ratio measurement was performed using bare and cadmium covered gold foils and measured to be 2.05 ± 2.9%. The ERS is a category I facility signifying it has the highest possible rank a radiography station can achieve.
The neutron energy spectrum was measured using foil activation coupled with unfolding algorithms provided by the software package unfolding with MAXED and GRAVEL (UMG). The Monte-Carlo N-Particle (MCNP6) transport code was used to assist with the unfolding process. UMG, MCNP6, and measured foil activities were used to determine a neutron energy spectrum which was implemented into the MCNP6 model of the ERS to contribute to future studies.
Key Words: Neutron Beam Characterization, Neutron Radiography, NRAD, Neutron Energy Spectrum, Neutron Flux. |