Neutron radiography for post-irradiation examination

Non-destructive inspection techniques are used in post-irradiation examination to observe the internal structure of irradiated materials; it provides useful information for the ensuing steps of examination. Application of neutron radiography has been considered since early years, to utilize the property of thermal neutrons to pass through heavy metals, while suitable methods of handling can obviate problems of radiation from the irradiated materials. In this study the irradiated samples were transferred from a hot cell to the neutron radiographic facility in JRR-3 (Japan Research Reactor No. 3). Photographs of the neutron radiography obtained and exposure chart are presented, and a discussion is given on the sensitivity of steel. (auth.)