Nuclear power plants can become heavily contaminated with fission and corrosion products during their operational lifetime. These contaminated materials give rise to high doses of radiation and heat, increasing risk to workers and the surrounding environment. Rapid identification of radionuclides and the extent of their penetration into nuclear materials could help reduce the volume of intermediate level waste (ILW) produced during decommissioning and minimise the costs of post operation clean out (POCO) procedures. Characterisation of legacy samples provides key insight into the long-term contamination effects of storing nuclear waste and is vital towards developing an appropriate strategy for future decontamination and decommissioning tasks. A concrete core was obtained during the decommissioning of the Hunterston A spent fuel storage pond. The core was taken from the middle of the pond wall, where it was exposed to the contaminated pond water. A multi-layered protective coating was applied to the concrete walls during plant operations to prevent uptake of radionuclides. The majority of the activity of the core is due to the presence of 90Sr, 137Cs, 241Pu, and 241Am which has been shown to be associated with the painted surface. Autoradiography results have also indicated that some activity may have penetrated through to the bulk concrete. Sorption experiments were completed using concrete coupons in stable Sr, Cs, or Co doped solutions to determine the effects of contamination within the bulk concrete material. Samples were analysed using Laser-Induced Breakdown Spectroscopy (LIBS) to assess its capability as a rapid, multi-elemental characterisation technique within the nuclear industry. Furthermore, plastic samples were taken from a pontoon which was floated on the pond water and used by workers during decontamination operations to reach the inside of the pond walls. Jet washing of the pond walls caused the wastewater to splash on top and down the sides of the pontoons, contaminating them in the process. Gamma spectroscopy indicated that the radioactivity within the samples is predominantly caused by 137Cs and 241Am. Autoradiography was performed on these discs to map the location of the radiation and identify areas of increased contamination for further analysis. LIBS analysis was also carried out to further evaluate its ability to identify radionuclide species on materials used throughout the nuclear industry at concentrations found in-situ.

Characterisation of materials from the Hunterston A spent nuclear fuel storage pond

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.