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Release of certified reference material for nuclear decommissioning: Stainless steel disks containing 60Co.

 Stainless steel disks containing 60Co
Jul 17 2019

The decommissioning of a nuclear installation is the final step in its lifecycle. It involves all activities from shutdown and removal of nuclear material to the environmental restoration of the site.

By 2025, it is estimated that over one third of the EU's currently operational reactors will have reached the end of their lifecycle and will be shut down.

The European Commission (EC) helps to address the funding of nuclear decommissioning through a group of experts known as the decommissioning funding group. These experts provide up-to-date knowledge on decommissioning costs and the management of funding and explore ways to further co-operation and harmonisation of nuclear decommissioning at European level.

The Joint Research Centre (JRC) of the EC is also supporting these activities by e.g. giving training courses for people working in the field of decommissioning and by developing calibration standards that can be used in the field of nuclear decommissioning.

Taking into consideration the large amount of material and the high cost of radioactive waste disposal, the EC issued Council Directive 2011/70/Euratom stating that: "Generation of radioactive waste shall be kept to a minimum which is reasonably practicable in volume and activity by means of appropriate design measures and of operating and decommissioning practices including the recycling and reuse of materials."

The JRC included in its work programme the development of a reference material that can be used in the area of the free release of metals. A stainless steel disk having similar dimensions as a typical test sample used in recycling facilities was spiked with 60Co. This radionuclide is the most encountered radionuclide in metallic waste streams. Moreover 60Co is often used as a scaling factor to correlate the massic activity of difficult to measure radionuclides with the one of 60Co.

Two different batches of disks were produced having a different massic activity, close to the free release limit of 60Co as laid down in council directive 2013/59/Euratom. The material was characterised using analytical results of gamma-ray spectrometry analysis performed by 5 different expert laboratories. As (stable) cobalt is a component of stainless steel, also the 60Co is very homogeneously distributed and stable in the matrix. This results in small uncertainty contributions of the homogeneity and stability to the total uncertainty of its massic activity.

The certified reference material is an asset to all laboratories and remelting facilities dealing with metal samples. They can use it as a calibration standard and to assess the performance of their analytical equipment.

More information you find on the Reference Materials catalogue

Read more in: http://publications.jrc.ec.europa.eu/repository/bitstream/JRC116895/certification_report_eurm_800_and_801.pdf