The design, fabrication and safety evaluation of a novel spent fuel storage basket material

• Neutron absorption performance of the novel neutron absorbing material was improved by adding three different kinds of neutron absorbers (LiF, Sm2O3, and Gd2O3).
• The percentage of the three kinds of neutron absorbers was optimised by Monte Carlo method.
• Carbon fibre and polyimide were used to enhance its mechanical behaviour and thermal behaviour.
• The radiation effect of the neutron absorbing material had been studied under Co-60 irradiation, and its irradiation-resistance performance was evaluated.

A novel LiF, Sm2O3, Gd2O3/carbon fibre/polyimide material was designed in order to improve the neutron absorbing performance of the spent fuel storage basket in this paper. The volume fraction of three kinds of neutron absorbers (LiF, Sm2O3and Gd2O3) in polyimide was optimised by Monte Carlo method. Calculation results showed that the novel neutron-absorbing material, in which the volume ratio of LiF, Sm2O3and Gd2O3 was 1:2:13, can achieve the best absorption capacity. Based on the calculated results, the basket material was fabricated by compression moulding, and its mechanical behaviour, thermal behaviour, and irradiation resistant behaviour were evaluated, respectively. The experimental results proved that the tensile strength of the novel neutron-absorbing material was between 195 and 346 MPa and the maximum service temperature was up to 300 °C. Gamma irradiation dose was limited to 160 kGy, the bending strength of the material kept increasing from 10 to 19 MPa.