Even when the operators shut down some automatic systems, the containment was sufficient to prevent any elevated radiation doses to anyone. In the past, some reactors were built without employment of the full defence in depth principle. Had there been multiple layers of safety systems at the Chernobyl power station, the major accident that occurred in April 1986 would have been contained and not had the disastrous consequences that eventuated. This is the principal difference between a nuclear power station and all other electricity generation facilities. Workers are kept at a distance from radiation sources, whenever possible, with robotics and remote handling techniques frequently being employed.
Shielding is used to reduce radiation levels.
The time spent by workers in high radiation areas is limited, with work being pre-planned, and sometimes rehearsed, to avoid unnecessary exposure time. Workers in a nuclear power station wear radiation measuring devices, and ambient radiation levels in the workplace are monitored. In general, the radiation exposures received by power station employees are only a small fraction of the maximum permissible under the applicable regulations. There are a number of different types of radioactive waste resulting from the operation of nuclear power plants. Spent fuel is produced by a power reactor throughout its working life.