Design and simulation of neutron radiography system for an aqueous homogeneous solution reactor

AHR reactors are known for the production of radiopharmaceuticals. The ARGUS reactor is one of the most famous of these reactors, which has been designed originally for radioisotopes production. The ARGUS reactor produces a suitable neutron flux that can be used for other applications such as neutron radiography (NR). Here, a NR system is designed step by step using the Monte Carlo method. The length of the collimator, divergence angle, diameter of the aperture, and thermal column dimension are designed. The designed aperture and thermal column are selected from boron carbide and heavy water, respectively. The depth of the thermal column is changed until the ratio of thermal neutrons to total neutrons (TNC) reached above 90%. The hole inside the thermal column is designed and internal lining is done. The inner lining is made of cadmium and had a thickness of 1 mm, and the space between the inner and outer lining is filled with lead. To reduce the gamma dose to acceptable values, the position of the collimator is changed instead of using a gamma filter. By changing the depth of the hole and creating the convergence angle to the hole, the flux of thermal neutrons will be 1.8E+6 n.cm −2 s −1 that satisfy the IAEA suggested values for NR. Then, the uniformity of the radiation field of the neutron flux output from the collimator is obtained. At the end, images of SI and BPI standards are recorded. The good quality and contrast of these images showed the acceptable design of the NR system for the ARGUS reactor.