Monitoring Noble Gases (Xe and Kr) and Aerosols (Cs and Rb) in a Molten Salt Reactor Surrogate Off-Gas Stream Using...

Area of Science:

• Nuclear Engineering
• Analytical Chemistry
• Spectroscopy

Background:

• Molten salt reactors (MSRs) produce fission products that evolve into the cover gas.
• Effective monitoring of off-gas streams is crucial for MSR safety and operation.
• Gaseous (Xe, Kr) and aerosol (Cs, Rb) species are key components of MSR off-gas.

Purpose of the Study:

• To evaluate laser-induced breakdown spectroscopy (LIBS) as a tool for monitoring MSR off-gas.
• To develop and validate univariate and multivariate models for quantifying specific fission products.
• To assess the real-time monitoring capabilities of LIBS for MSR off-gas analysis.

Main Methods:

• Utilized surrogate materials to simulate MSR off-gas composition.
• Applied univariate models to analyze peak intensities of Xe and Kr.
• Developed multivariate models using partial least squares regression with data preprocessing.
• Validated models using independent samples and tested real-time performance with controlled gas flow.

Main Results:

• Univariate models showed high correlation for Xe (R²=0.983) and Kr (R²=0.997).
• All calibration models were successfully validated at a 99.9% confidence interval.
• Real-time monitoring tests demonstrated successful quantification of Kr with low RMSEP values (0.051-0.121 mol%).

Conclusions:

• LIBS is a robust and promising technique for online monitoring of gaseous and aerosol species in MSR off-gas.
• Validated univariate and multivariate models provide accurate quantification of target analytes.
• The LIBS system demonstrates capability for real-time, accurate online monitoring essential for MSR operations.