Fig. 3-1 Braided aramidfiber reinforced composite Aramidfiber is woven into a braided rope, impregnated with a new epoxy resin, and cured into a rod, which is fully composed of organic compounds.

Fig. 3-2 Radiation resistivity of the aramidfiber reinforced composite The radiation resistivity of the new composite was found to be 30 to 50 times higher than that of conventional composites, when compared at irradiation levels at which the same relative tensile strengths were obtained.

In planned fusion reactors, the deterioration of the ferro-concrete structure materials is known to be accelerated by the electric current induced by the strong magnetic field. To combat this deterioration, and it is desirable to develop a insulating radiation-resistant material which can replace the iron reinforcing rod. We successfully developed a radiation- resistant concrete-reinforcing material which is composed of braided fibers of an aromatic polyamide (aramidfiber) and a new epoxy-resin containing styrene oxide. The excellent processability and the homogeneous penetration of the new epoxy resin lead to an organic fiber reinforced composite which can be molded into a long rod with a diameter of 3 to 25 mm and which has an excellent tensile strength (1.6 MPa). The tensile strength to weight ratio of the new composite was found to be up to 15 times higher than that of the iron used for reinforcing rods. The radiation resistivity of the composite was 30 to 50 times higher than those of more conventional composite materials, with its mechanical strength barely decreasing even after exposure to 100 MGy gamma-ray irradiation. The new composite is very suitable for use in the construction of common buildings as well as in fusion reactor buildings, since it provides protection from the electromagnetic damage to electronic equipments that can be caused by lightning strikes. The new composite is also expected to be used as a concrete structure material in many emerging applications, such as in the traffic system of the linear-motor car and in the superconducting electric power storage station.

Reference A. Udagawa et al., Development of High Radiation Resistant Aramidfiber Reinforced Polymer Composite for Concrete Reinforcement, Genshiryoku Kogyo, 43 (6), 34 (1997).

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