A new analysis workflow for discrimination of nuclear grade graphite using laser-induced breakdown spectroscopy

Area of Science:

• Nuclear Chemistry
• Analytical Chemistry
• Materials Science

Background:

• Radioactive waste characterization is crucial for safe management and disposal.
• Nuclear-grade graphite presents significant decommissioning challenges due to long-lived isotopes like Carbon-14 and Chlorine-36.
• Remote material differentiation is essential for hazardous environments.

Purpose of the Study:

• To develop and validate a Laser Induced Breakdown Spectroscopy (LIBS) workflow for discriminating nuclear-grade graphite from other waste materials.
• To demonstrate the capability of LIBS for rapid, stand-off analysis of radioactive waste surrogates.
• To reduce the costs associated with nuclear decommissioning through enhanced material characterization.

Main Methods:

• Stand-off, in-situ Laser Induced Breakdown Spectroscopy (LIBS) was employed.
• A novel analysis workflow integrating spectral characteristics, multivariate analysis, and molecular isotopic spectroscopy was developed.
• Nuclear 'Pile Grade A' (PGA) graphite and lumpwood charcoal were used as surrogates for waste discrimination.

Main Results:

• LIBS successfully discriminated between nuclear-grade graphite surrogates and other carbon-bearing wastes.
• The proposed workflow enables rapid segregation of graphite from heterogeneous waste streams.
• The developed method shows potential for significant cost reduction in nuclear plant decommissioning.

Conclusions:

• LIBS is a viable and effective technology for the rapid, remote characterization and discrimination of nuclear waste materials.
• The integrated analysis workflow enhances the accuracy and efficiency of waste segregation.
• Improved characterization techniques can substantially lower the economic burden of legacy nuclear site decommissioning.