Characterising legacy spent nuclear fuel pond materials using microfocus X-ray absorption spectroscopy

Area of Science:

• Environmental Science
• Materials Science
• Nuclear Chemistry

Background:

• Radioactive contamination in nuclear facilities poses challenges for decommissioning.
• Understanding radionuclide behavior in concrete infrastructure is crucial for safe waste management.

Purpose of the Study:

• To analyze radionuclide distribution and binding in a radioactive concrete core from a nuclear cooling pond.
• To investigate the interaction of stable strontium (Sr) and cesium (Cs) with concrete phases.

Main Methods:

• Microfocus X-ray fluorescence (μXRF) and X-ray absorption spectroscopy for surface analysis.
• Scanning electron microscopy and chemical analysis for radionuclide characterization.
• Stable Sr and Cs sorption experiments on concrete coupons.

Main Results:

• Radioactivity, primarily cesium-137 (Cs) and strontium-90 (Sr), was heterogeneously distributed on painted concrete surfaces.
• Sr in paint layers was associated with titanium dioxide (TiO2) particles.
• Stable Sr was immobilized by cement phases, while Cs associated with clay minerals at higher concentrations.

Conclusions:

• The study provides insights into radionuclide behavior within complex infrastructural contamination scenarios.
• Findings are directly applicable to nuclear decommissioning strategies in the UK.
• Understanding radionuclide-material interactions is key for managing radioactive waste.