Novel assays of ‘difficult-to-measure’ radionuclides in the context of a sustainable waste management

In Belgium, and across Europe, many nuclear installations are planned to be decommissioned in the near future [2] or are currently being decommissioned (e.g. BR3 at SCK CEN, particle accelerators). Two paths are considered in a sustainable radioactive waste management for nuclear wastes: (1) free release in the environment or (2) with appropriate disposal procedures confined from the environment [1]. In either of the selected paths, a good radiological characterization of the materials is of paramount importance. Waste products characterisation is commonly based on non-destructive assay (NDA) however, pure beta or alpha emitters cannot be readily quantified in this way and destructive techniques are required to complete the information. Those radionuclides are considered as ‘difficult-to-measure’.

The recently published conformity criteria for cAt disposal in Belgium of radioactive waste lists limiting activity concentrations for radionuclides [2], amongst which several of them are difficult-to-measure.

This project will focus on several of these difficult-to-measure radionuclides (⁴¹Ca, ^108mAg, ¹²⁶Sn, ⁹³Zr, ¹⁰Be) because of their relevance in the Belgian Waste Mangement and for the technical and scientific challenges related to the radiochemistry and their radiometric quantification techniques.

The PhD study involves developing validated, traceable and robust analytical methods for the selected radionuclides considering the following challenges:

• currently no reference materials are available (radionuclides in specified materials);
• many radiometric interferences should be mitigated by optimizing/developing radiochemical separation procedures for the different waste products;
• the measurement accuracy and detection limits of the methods should comply with the conformity criteria defined by NIRAS [2].

[1] William L. Lennemann, Radioactive Waste Management, IAEA BULLETIN-VOL.18, NO. 5/6

[2] NIRAS 2019. Conformiteitscriteria voor bergingscolli - Hoofdstuk 15 uit het veiligheidsrapport voor de oppervlaktebergingsinrichting van categorie A-afval in Dessel

The minimum diploma level of the candidate needs to be

• Master of sciences

The candidate needs to have a background in

• Chemistry
• Radiochemistry

Estimated duration

4 years

Expert group

Low-level Radioactivity Measurements