The degradation of the inter-laminar shear strength (ILSS) of GFRPs was evaluated after electron irradiation at 77K and reactor irradiation at 20K. The GFRPs used in this study were prepared by varying matrix resins. Optical microscopic observation of the fracture surface was carried out to reveal the degradation behavior of the ILSS. The exposed fiber area of the fracture surface was found to depend on the absorbed dose. This suggests that a change in ILSS is induced by the interface failure between fiber and matrix as a result of the change in matrix resin.
