Since August 2015 a new classification of radioactive waste was issued by Italian Ministry of Economic Development, in order to adapt Italian historical classification to European standards. This new classification provides 6 categories, from exempt to high level waste, and it is based on the waste final destination: from free release to final disposal or interim storage (high level waste and intermediate level waste with α-content higher than 400 Bq/g) [1].
Nucleco is a State owned Company acting as Waste Management Organization for radioactive waste coming from hospitals, industries and research and development activities not related to electricity production by nuclear plants. Nucleco collects, safely manages and temporarily stores waste that will be sent to the National Repository (site definition phase is still ongoing), while for the Short Lived Radionuclides and Very Low Activity waste Nucleco performs all necessary operations to be compliant with the conditions of release prescribed by the Italian Control Authority.
Short Lived Radionuclides are those whose half-life is shorter than 100 days or reach the condition of non-radiological relevance in 5 years: they are mainly produced by bio-medical applications of radioactive materials. Very Low Activity waste are characterized by activity concentrations lower than 100 Bq/g (of which less than 10 Bq/g of α-emitting radionuclides) and reach the condition of non-radiological relevance in 10 years: these waste usually came from research institutions and industrial activities.
This work presents the authorized operating procedures, the radiological measurements criteria and the technical know-how put in place by Nucleco to fulfil the provisions of Italian regulations for unconditioned release of radioactive waste.
A case study of ISO 20’ containers is discussed in the current paper.
Main emphasis will be addressed to:
• gathering of historical information about the state of the material to be released and definition of the reference radiological spectrum;
• sampling procedures to ensure representativeness of the samples from homogeneous waste batch to be released and then subjected to radiological characterization;
• characterization phase consisting of the integration of several state-of-art techniques aiming to collect the most complete set of radiological data;
• data processing protocols needed for the calculation of the activity concentrations for each radionuclide of the reference spectrum (or other radionuclides eventually detected);
• evaluation of the main sources of uncertainty affecting the results;
• comparison of the activity concentration (including the uncertainty) of each radionuclide with the corresponding authorized concentration limits.
