Types of radioactive waste investigated in the CAST project
Nature and effects of processes and events used to assess the safety of geological disposal facility must be considered for timescales of hundreds of thousands of years. This newsletter intends to inform stakeholders with a general interest in the CAST project.
Carbon-14 is a natural radioactive substance (radionuclide) that is continuously generated in our atmosphere and on the Earth’s surface, from nuclear reactors. Carbon-14 is radioactive, but does not present an external radiation hazard as the radiation cannot penetrate the skin. When the radiation dose mainly comes from this radionuclide, e.g. irradiated graphite, remote handling or shielding is not necessary. Carbon-14 is used to determine the age of objects with biological origin, such as bone, cloth, wood and plant fi bers. The incorporation of carbon-14 stops when the organism dies and its content decreases by radioactive decay over time. By counting the carbon-14 concentration, age can be determined up to about 50,000 years old. The chemical forms determine how easily carbon-14 can be assimilated. This is why it is important to understand how carbon-14 is released from radioactive waste. The types of radioactive waste investigated in the CAST project are introduced in this newsletter.