HKNIC - Station Decommissioning

Station Decommissioning

All power stations have a limited lifespan and will ultimately become uneconomic to operate and maintain. At the end of its life, a power station needs to be decommissioned and demolished, and the site cleaned up or decontaminated before being released for general use.

A nuclear power station is typically designed for a 40-year lifespan. Older plants have a shorter design life of typically 30 years, while more modern plants have a typical design life of 60 years. However, comprehensive regulatory reviews in the US have shown that their currently installed pressurised and boiling water reactors are capable of operating for 60 years because of the general robustness of their design. Since the Daya Bay design is similar to the pressurised water reactors in the US, it is reasonable to expect it to operate for 60 years given careful operation and maintenance.

Decommissioning a nuclear power station requires removing its radioactivity and dismantling the facilities. Removing the nuclear fuel after the station has shut down permanently removes most of the radioactivity at the site. Apart from any surface contamination on the equipment at the plant, other sources of radioactivity come from plant components that have received substantial neutron bombardment and have therefore become radioactive. Depending on government policy, these items of equipment can be removed within a few years after station closure, hence releasing the site early. Alternatively, the facility can be kept in safekeeping for several decades so that the level of radioactivity falls substantially before the site is cleared. Plant facilities that are unaffected by radioactivity can be dismantled soon after the permanent shutdown of the nuclear power station.

Station Decommissioning

Image Credit: DNMC

Decommissioning of some old nuclear power stations is underway, with decommissioning of a number of them already completed, offering useful experience for future decommissioning activities.

The cost of decommissioning a nuclear power station is usually included as part of the operating cost and is recovered as part of the cost of electricity produced. While the cost may vary between different types of nuclear reactors, it is usually a small proportion of the cost of building the nuclear power station.