SPS technique for ionizing radiation source fabrication based on dense cesium-containing core.

Current ionizing radiation sources often use cesium-137, a material with safety concerns and regulatory restrictions. Traditional fabrication methods fail to produce stable, non-dispersible cores that meet modern safety standards. While prior research has shown cesium-based materials can emit ionizing radiation, no prior work had resolved the challenge of safely encapsulating cesium in a durable matrix. This gap motivated the search for alternative fabrication techniques. Existing methods lack the precision to control leaching rates and mechanical integrity. The need for a scalable, safe fabrication process remains unmet. Regulatory bodies like the IAEA have prohibited certain cesium compounds, increasing the urgency for safer alternatives. The absence of a high-density, radiation-resistant matrix design has limited progress in this field.

This study aimed to develop a novel fabrication method for ionizing radiation sources using cesium-containing materials. The goal was to replace unsafe commercial products with a safer, non-dispersible core. The researchers focused on spark plasma sintering (SPS) to produce dense, radiation-resistant matrices. The specific problem addressed was the inability of existing methods to achieve sufficient mechanical strength and low leaching rates. The motivation stemmed from the need to comply with IAEA regulations and improve safety. The study sought to optimize SPS parameters for reliable, large-scale production. The objective was to create a material that could be safely sealed in radiation-resistant steel containers. The researchers aimed to validate the feasibility of using zeolite-based materials for IRS fabrication.

Spark plasma sintering (SPS) was used to fabricate dense matrices from cesium-containing zeolite. The process involved optimizing sintering temperature, pressure, and time to achieve high-quality cores. X-ray diffraction (XRD) confirmed the crystal structure of the sintered materials. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyzed surface morphology and elemental composition. BET surface area measurements assessed porosity. X-ray fluorescence spectroscopy (XFS) and solid-state MAS NMR ¹³³Cs methods evaluated structural and chemical properties. The sintering temperature was kept below 1000 °C to avoid degradation of cesium compounds. The final product was sealed in radiation-resistant steel containers for stability.

The SPS process produced dense ceramic and glass-ceramic matrices with cesium content of 13.5 wt.%. The sintered cores achieved a density of 99.8% of theoretical values. Compressive strength reached approximately 477 MPa, indicating high mechanical stability. Leaching rates were measured at 10^-4 to 10^-6 g cm^-2 day^-1, meeting safety standards. XRD and SEM confirmed uniform microstructure and minimal porosity. The sintering temperature of less than 1000 °C preserved cesium integrity. Pressure of 24.5 MPa and heating duration of 13 minutes yielded optimal results. The material showed exceptional physico-chemical properties suitable for radiation source applications.

The study demonstrated that spark plasma sintering can produce high-quality, cesium-containing cores for ionizing radiation sources. The material met mechanical and chemical stability requirements for safe use. The leaching rates and compressive strength suggest suitability for large-scale fabrication. The results align with the properties of existing Russian products like RSL and M37C. The optimized SPS parameters provide a reliable method for industrial application. The material's density and structural integrity support its use in radiation-resistant steel containers. The findings suggest that this approach can replace unsafe commercial cesium sources. The study supports the feasibility of using zeolite-based materials for IRS fabrication.