| Abstract [eng] |
Graphite is widely used as a moderator, reflector, and fuel matrix in various types of nuclear reactors. Over 250,000 tons of irradiated graphite is temporarily stored in interim storage facilities at nuclear power plants worldwide and each country decides individually how to handle this waste. The total mass of graphite at Ignalina Nuclear Power Plant (INPP) in Lithuania is ~3 820 tons. Graphite as a major structural component material of the RBMK-1500 nuclear reactor core is subjected to high levels of radiation, which affects both physical and chemical properties of material. In order to optimize the disposal strategy of the irradiated graphite waste, the radiological and structural characterization of graphite is needed. In this work, the concentrations of the several impurities in different types of the RBMK-1500 reactor graphite (stack (GR-280), bushing and sleeve (GRP-2-125)) are determined for the first time. Moreover, the rapid analysis method for the experimental determination of specific 14C activity in irradiated graphite is proposed and applied. The radiological and structural characterization of RBMK-1500 reactor graphite is carried out both experimentally and theoretically. Based on the reactor operational conditions the ion implantation method is applied and the new data about structural properties of the RBMK-1500 reactor graphite are presented. The complex analysis of the 14C activity distribution in the irradiated RBMK-1500 reactor graphite is provided. |
