In Sweden, spent nuclear fuel is stored for a number of years at an interim storage facility (CLAB) in Oskarshamn. We have qualified staff for handling nuclear fuel and work involving e.g. servicing and maintenance in reactor tanks.
During outage periods and other times, our staff are engaged for this type of work to complement the power plant’s own organisations. Nuclear fuel comprises cylindrical pellets of uranium dioxide in ceramic form. The pellets are enclosed in fuel rods that combine to form a bundle – the fuel element. The fuel remains in the reactor for around five years before it is replaced. The nuclear reactions in the reactor give rise to new atoms with a surplus of internal energy. This means that the spent nuclear fuel is still radioactive and thus emits radiation. Before the spent fuel is moved to CLAB, it has been stored in the nuclear power plant’s own storage basins for at least nine months. During this period the majority of the radioactive substances that have formed in the fuel decay. However, the radioactivity in the nuclear fuel is still very high, which means it must be radiation-shielded and cooled. After approximately 30 years’ storage at CLAB, the radioactivity has reduced by a further 90%, but the fuel must still be radiation-shielded.