Development of techniques for the neutron radiography of CF188 flight control surfaces

A neutron radiography facility previously installed on the SLOWPOKE-2 research reactor at the Royal Military College of Canada has been used to gain experience with the inspection of flight control surfaces from the CF188 fighter aircraft. Through operating the facility in a temporary manner in terms of handling and shielding for this application, over 500 radiographs were made for more than three aircraft. Moisture and corrosion were discovered in the honeycomb structure and hydration was found in the composite and adhesive layers. The experience also indicated a need to characterize the neutron beam, to decrease the exposure time by finding a faster film and conversion screen combination, and to develop a gauge to evaluate the moisture trapped in the honeycomb cells of flight control surfaces.