Cesium emissions from laboratory fires

Area of Science:

• Environmental Science
• Radiological Health
• Fire Science

Background:

• Radiological incidents can contaminate large areas, including forests.
• Forest fires in contaminated zones pose risks of airborne radionuclide release.
• Cleanup priorities often leave forest floor materials to accumulate over time.

Purpose of the Study:

• To investigate the partitioning of cesium-133 during simulated wildfire events in contaminated forest biomass.
• To quantify the amount of cesium released into the air versus remaining in ash.
• To inform risk assessments for public and firefighter exposure.

Main Methods:

• Laboratory simulation of wildfire conditions using pine needles and peat doped with cesium-133.
• Analysis of airborne particulate matter and residual ash for cesium concentration.
• Characterization of airborne cesium-containing particles by aerodynamic diameter.

Main Results:

• Only 1-2.5% of cesium from doped pine needles was emitted as airborne particulate matter.
• The majority of emitted cesium from pine needles was found in particles >10 µm aerodynamic diameter.
• Virtually all cesium from doped peat remained in the residual ash; duff did not contribute to airborne cesium.

Conclusions:

• Wildfires in radionuclide-contaminated forests have a limited potential for cesium emission, primarily from pine needles.
• Cesium emissions are concentrated in larger particulate matter, potentially reducing widespread atmospheric dispersal.
• Findings support the understanding of radionuclide behavior during forest fires for risk management.