Investigation of Multi-parameter Synchronous Detection Technology for Radioactive Aerosols in Spent Fuel Dissolution...

Area of Science:

• Nuclear Engineering
• Radiological Sciences
• Environmental Monitoring

Background:

• Spent-fuel dissolution generates multi-nuclide, high-activity aerosols.
• Existing gross alpha/beta continuous air monitors (CAMs) suffer from interference and slow response, hindering timely dose assessment and alarms.

Purpose of the Study:

• To develop and evaluate an integrated multiparameter synchronous detection system for simultaneous measurement of aerosol activity concentration, spectra, and particle size.
• To improve the accuracy and speed of radiological monitoring in spent-fuel processing environments.

Main Methods:

• Integrated sampling with optical particle sizing (0.1-10 μm) and silicon (α), thin-window proportional (β), and NaI(Tl) (γ) detectors.
• Digitized signal processing for pulse-shape discrimination and high-resolution spectrometry (8,192 channels).
• Performance validation following ISO 11929/Curie standards using standard sources and mixed-nuclide aerosols.

Main Results:

• Achieved detection efficiencies of 26.3% (α), 42.5% (β), and 31.2% (γ).
• Demonstrated minimum detectable activities as low as 8.5 × 10⁻⁷ Bq cm⁻³ for ²⁴¹Am.
• Reduced response time (T90 = 17.5 s) and α/β misclassification (<5%), with spectral resolving power improved ≈5-fold compared to representative CAMs.

Conclusions:

• The multiparameter system significantly enhances spectral resolution and reduces response time for aerosol monitoring.
• Improved nuclide identification and particle size information minimize dose-assessment bias and shorten alarm latency (<30 s).
• Supports ALARA principles and process control in challenging high-background, multi-nuclide environments during spent-fuel dissolution.