A survey was conducted from 2006 to 2008 on the normal transport of radioactive material carried by sea to and from the UK, and assessments were made of the resulting radiation doses to workers and members of the public. It was found that some 30,000 packages are transported annually by sea to and from the UK in about 1000 consignments.
The radiological consequences of these shipments were found to be very low. The highest annual radiation dose to any dock worker or ships’ crew member was found to be 0.2 mSv, and the majority receive annual doses of only a few microsieverts or less.
Almost all of these annual consignments are made by cargo ship or ferry and only a small proportion of the total is made by passenger ferry. The annual dose to a general member of the public from the latter was found to be less than one microsievert. The annual collective dose arising from despatch, receipt and shipment of these materials to and from the UK was assessed to be around 2 × 10-3 man Sv.