Optimization of laser-induced breakdown spectroscopy for liquid sodium analysis.

Area of Science:

• Nuclear Engineering
• Analytical Chemistry
• Materials Science

Background:

• Next-generation nuclear reactors utilize liquid sodium coolant for enhanced efficiency and safety.
• Fast breeder reactors offer higher fuel burn-up and reduced waste compared to current technologies.
• Monitoring sodium coolant impurities is critical to prevent cooling system blockages and hazardous reactions.

Purpose of the Study:

• To develop and evaluate laser-induced breakdown spectroscopy (LIBS) for impurity detection in liquid sodium.
• To assess the performance of a custom-built immersion probe for LIBS analysis in a sodium environment.
• To confirm the suitability of LIBS for real-time monitoring in nuclear reactor systems.

Main Methods:

• Laser-induced breakdown spectroscopy (LIBS) was applied to a liquid sodium sample.
• A custom-built immersion probe was used for laser delivery and signal collection within an argon atmosphere.
• The influence of probe parameters (height, immersion) and argon flow rates on signal stability and quality was investigated.

Main Results:

• Sodium, potassium, and oxygen signatures were successfully obtained from the liquid sodium sample.
• Probe height and immersion significantly impacted signal level and stability.
• Stable signals were observed across argon flow rates of 2-5 L/min, indicating a laminar flow regime.
• A high signal-to-noise ratio was achieved for impurity elements.

Conclusions:

• Laser-induced breakdown spectroscopy with a custom immersion probe is a suitable technique for detecting impurities in liquid sodium.
• The method offers reliable impurity detection and monitoring capabilities for advanced nuclear reactor environments.
• The findings support the use of LIBS for ensuring the safety and operational integrity of sodium-cooled reactors.