A generic mixing system for achieving conditions suitable for single point representative effluent air sampling

Area of Science:

• Environmental Science
• Chemical Engineering
• Industrial Hygiene

Background:

• Radionuclide aerosol particle sampling is critical for U.S. Department of Energy (DOE) facilities.
• Existing methods often require specific flow conditions for accurate sampling.
• U.S. Environmental Protection Agency (EPA) approval is necessary for alternate methodologies.

Purpose of the Study:

• To present EPA-approved Alternate Reference Methodologies for radionuclide aerosol particle sampling.
• To introduce a generic mixing system for stacks and ducts lacking adequate flow mixing.
• To validate the effectiveness of the mixing system for single-point sampling.

Main Methods:

• Utilized single-point sampling with shrouded probes in well-mixed flow cross-sections.
• Developed and implemented a generic mixing system for non-ideal stack and duct configurations.
• Measured coefficients of variation for velocity, tracer gas, and aerosol particle profiles.

Main Results:

• Achieved coefficients of variation below 10% for velocity, tracer gas, and 10 micrometer aerodynamic diameter aerosol particles.
• Demonstrated that the mixing system's effectiveness is independent of system size and flow rate in turbulent flow.
• Confirmed results are well within the EPA's acceptable limit of 20% variation.

Conclusions:

• The developed mixing system effectively creates conditions suitable for single-point sampling.
• Alternate Reference Methodologies, including the mixing system, are validated for radionuclide aerosol particle sampling.
• These advancements support regulatory compliance and enhance safety at DOE facilities.