Precise radiocarbon determination in radioactive waste by a laser-based spectroscopic technique

Area of Science:

• Nuclear chemistry
• Analytical chemistry
• Spectroscopy

Background:

• Accurate radionuclide inventory determination is vital for nuclear waste management and decommissioning.
• Radiocarbon ([Formula: see text]) is a difficult-to-measure isotope, typically requiring complex Accelerator Mass Spectrometry (AMS) or Liquid Scintillation Counting (LSC).
• Existing methods like AMS have limited global availability, while LSC involves non-trivial sample preparation.

Purpose of the Study:

• To demonstrate the efficacy of laser-based saturated-absorption cavity ring-down (SCAR) spectroscopy for [Formula: see text] determination in nuclear waste.
• To present SCAR as a mature and accurate alternative to current [Formula: see text] analysis techniques.
• To validate SCAR results against established methods like AMS.

Main Methods:

• Utilized saturated-absorption cavity ring-down (SCAR) spectroscopy for [Formula: see text] analysis.
• Performed proof-of-principle experiments on nuclear waste samples (graphite and concrete).
• Compared SCAR results with existing Accelerator Mass Spectrometry (AMS) data.

Main Results:

• Achieved consistent results between SCAR and AMS for [Formula: see text] determination.
• Determined mole fractions of 1.312(9) F[Formula: see text] and 30.951(7) F[Formula: see text] in graphite samples (∼1.5 and 36.2 ppt).
• Measured a mole fraction of 0.593(8) F[Formula: see text] ([Formula: see text] ppt) in a concrete sample from a decommissioned reactor.

Conclusions:

• Laser-based SCAR spectroscopy is a viable, accurate, and mature alternative for [Formula: see text] content determination in nuclear waste.
• SCAR offers distinct advantages for radionuclide inventory assessment in nuclear decommissioning.
• The technique provides reliable data comparable to established methods, aiding waste management strategies.