Exposure to high levels of radiation can be dangerous. Measures to protect the public and workers from radiation and other hazards are being incorporated into all phases of our management of used nuclear fuel. This includes the safe transport of used fuel from current storage facilities, to its inspection and repackaging at surface facilities, and its long-term placement in the deep geological repository.
Used nuclear fuel contains radioactive nuclides which can emit ionizing radiation, and is most radioactive when it is first removed from the reactor. While the radioactivity diminishes over time, the used nuclear fuel remains hazardous, essentially indefinitely.
Radiation can either be ionizing or non-ionizing. The forms of ionizing radiation are alpha particles, beta particles and neutrons, as well as X-rays and gamma rays. Ionizing radiation have enough energy to change the makeup of materials at their most basic level, the atom. If the exposure is beyond the body's natural repair processes, it may lead to uncontrolled growth of cells (i.e., cancer) or more serious health effects. Non-ionizing radiation does not have enough energy to cause atomic changes. The Canadian Nuclear Safety Commission provides a helpful and informative summary of the impacts of radiation on human health.
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