Radioactivity - The Changing Arctic Environment: The Arctic Messenger - page 55

Marine Discharge of Nuclear Wastes From Nuclear
Reprocessing Plants at Sellaield in the United
Kingdom and at Cap de la Hague in France
AMAP assessments found that the most widespread occurrence of radionuclides freely dis-
persed in the Arctic marine environment has not been from Cold War legacy sources in
northern Russia. The main source has been from long-term waste discharge from nuclear
reprocessing plants at Sellafield in the United Kingdom and at Cap de la Hague in France.
Theyarecalled“planned”discharges,meaningtheyhaveresultedfromthenormaloperation
ofthese facilities and not from an accident oranother malfunction. Reprocessing is the name
given to activities that recover uranium and plutonium from spent nuclear fuel so they can
be reused. Sellafield is located in north-western England. It is the only currently operating
nuclear reprocessing facility in the United Kingdom and its normal operational practice has
includedthedischargeoflow-levelradioactivewasteintotheIrishSea.Sellafielddischarges
of the long-lived fission product technetium-99 ( 99 Tc) briefly peaked during the late 1970s
to levels of more than 175 TBq per year. A terabecquerel (TBq) is 10 12 becquerels. From
then until 1993, discharges ran at about 5 TBq per year but then rapidly rose again after the
introduction in 1994 of a new process designed to eliminate a large backlog of waste. Dis-
charge of 99 Tc quickly reached levels of 190 TBq per year. Technetium-99 is highly soluble
in seawater and it is therefore unaffected by sedimentation processes (in contrast to plutoni-
um). Ocean currents have carried 99 Tc from Sellafield into the North Sea and northwards
into the Barents Sea. The transport time from Sellafield to the Norwegian monitoring station
at Hillesøy near Nordkapp is estimated to be about four years. By 2000, the annual average
activity concentrations of 99 Tc in the seaweed Fucus vesiculosus at Hillesøy was between
300 and 320 Bq per kilogram of dry weight and 99 Tc activity could be detected as far away
as the East Greenland Current.
The reprocessing facility at Cap de la Hague has also routinely discharged low-level
radioactive wastes into the sea, but the main concern here was with iodine-129 ( 129 I). In the