Sellafield Ltd found nearly 3,000 radioactive objects on the beaches surrounding the decommissioning facility between 2006 and 2016.
It monitored a total beach area of almost 1,900 hectares, to make sure discharges of radioactive waste from nuclear sites are being properly controlled and their effects on people and the environment are minimised.
A vehicle-mounted detector system is used to find radioactive objects, which are then taken from the beach and sent for laboratory analysis.
In total, 2,139 radioactive particles and 635 radioactive larger objects have been found.
Smaller objects, the size of a grain of sand or smaller are known as particles. Larger objects include grit, pebbles, stones and other items such as slivers of plastic or metal.
According to the Environment Agency, the bulk of the material is from incidents dating back decades and says it is necessary to carry out repeat surveys because the tides carry material from beach-to-beach.