Related goal
Releases, the risk of releases and the spread of radioactive substances that may cause damage to health or the environment will be minimised. All radioactive waste will be handled safely and in an approved manner.
Are we moving in the right direction?
The largest discharge of technetium-99 from Sellafield took place in 1995 and 1996. It takes three to four years for the discharge to reach the seawater at Hillesøy in northern Norway. The highest annual mean value of technetium-99 in sea water was therefore measured at Hillesøy near Tromsø in 1999.
There have been some reductions in levels after 1999 and concentrations have been stable for the last two to three years. The last untreated discharge of technetium-99 occurred in April 2003. A further reduction in technetium-99 in seawater is therefore expected.
The annual discharge of caesium-137 from Sellafield has remained at the same level for the last decade. The level of caesium-137 in seawater off Tromsø has also been relatively stable in later years.
The contribution of caesium-137 from the Chernobyl accident and the atmospheric nuclear weapons tests in the 1950s and 1960s diminishes with time, due to the decay of the radioactivity. Caesium-137 has a half-life of 30 years. A portion of the caesium-137 in the ocean will also fix to particles and sink to the seabed.