Assessment of doses and environmental contamination from decommissioning of the nuclear facilities at Risø

When a nuclear installation is to be dismantled in a Member State of the European Union the government should submit a document to satisfy the requirements in Article 37 of the Euratom Treaty on assessed contamination levels close to the site and in the nearest neighbouring country, and individual doses to the critical group and to individuals in the nearest neighbouring country.

The contamination levels and individual doses should be assessed from both routine and accidental releases. Almost all of the expected discharges of radioactive materials to the atmosphere from future decommissioning activities will come from operations inside the reactor vessel of DR 3 and during the cleaning operations in the concrete cells at the Hot Cell facility.

The physico-chemical form of the discharges from DR 3 would be as tritiated water and as very small particles (of the construction parts) containing activation products. The expected discharges from the Hot Cell facility would be as very small particles of irradiated fuel and contaminated dust. Only minor discharges of activity are expected to occur during the decommissioning operations at the reactors DR 1 and DR 2 and, if so, such discharges would be as very small particles of the reactor components.

The calculated doses to the critical group from both routine and accidental releases during decommissioning - and from both atmospheric and aquatic exposure – as presented in this paper appear to be only a very small fraction of the individual doses from the naturally occurring background radiation.