Irradiation of Polyimide and Neutron Poison Materials by Using a HANARO Capsule

A material capsule system has been developed for an irradiation test of non-fissile materials in HANARO (High flux Advanced Neutron Application ReactOr).This capsule system has been actively utilized for the various material irradiation tests requested by users from research institutes, universities, and the industries. The capsules were mainly designed for an irradiation of the RPV (Reactor Pressure Vessel) and reactor core materials, and Zr-based alloys of parts of nuclear fuel assembly. Recently, irradiation tests of neutron poison materials and Polyimide were requested by Westinghouse Electric Company (WEC) and Hanyang University, respectively. As a candidate material of control rod of AP1000 reactor, Ag and Ag-In-Cd alloys were requested to be irradiated in HANARO by WEC. Polyimide has been studied as a shielding material against thermal and fast neutrons. The irradiation of these new materials which might affect the safety of a reactor was carried out for the first time in HANARO. As a preliminary test, small amount of these materials were determined to be inserted in a KNF (Korea Nuclear Fuel) irradiation capsule of 07M-13N. Due to the new materials, the irradiation test of the 07M-13N capsule was examined and approved by the 'HANARO Safety Review Committee'. The 07M-13N capsule was safely irradiated for 95.19 days (4 cycles) in the CT test hole of HANARO of a 30MW thermal output at 230∼420 .deg. C. The specimens of these new materials were irradiated up to a maximum fast neutron fluence of 1.13x1021(n/cm2) (E>1.0MeV) and the dpa of the irradiated specimens were evaluated as 1.87