Single-point representative sampling with shrouded probes

Technical Report · Sun Aug 01 04:00:00 EDT 1993

DOI:https://doi.org/10.2172/10184150· OSTI ID:10184150

McFarland, A R ^[1]; Rodgers, J C ^[2]

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1. Texas A and M Univ., College Station, TX (United States). Aerosol Technology Lab.
2. Los Alamos National Lab., NM (United States)

The Environmental Protection Agency (EPA) prescribed methodologies for sampling radionuclides in air effluents from stacks and ducts at US Department of Energy (DOE) facilities. Requirements include use of EPA Method 1 for the location of sampling sites and use of American National Standards Institute (ANSI) N13.1 for guidance in design of sampling probes and the number of probes at a given site. Application of ANSI N13.1 results in sampling being performed with multiprobe rakes that have as many as 20 probes. There can be substantial losses of aerosol particles in such sampling that will degrade the quality of emission estimates from a nuclear facility. Three alternate methods, technically justified herein, are proposed for effluent sampling. First, a shrouded aerosol sampling probe should replace the sharp-edged elbowed-nozzle recommended by ANSI. This would reduce the losses of aerosol particles in probes and result in the acquisition of more representative aerosol samples. Second, the rakes of multiple probes that are intended to acquire representative samples through spatial coverage should be replaced by a single probe located where contaminant mass and fluid momentum are both well mixed. A representative sample can be obtained from a well-mixed flow. Some effluent flows will need to be engineered to achieve acceptable mixing. Third, sample extraction should be performed at a constant flow rate through a suitable designed shrouded probe rather than at a variable flow rate through isokinetic probes. A shrouded probe is shown to have constant sampling characteristics over a broad range of stack velocities when operated at a fixed flow rate.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 10184150
• Report Number(s): LA--12612-MS; LA-SUB--93-248; ON: DE93040695
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540130
560101
61 RADIATION PROTECTION AND DOSIMETRY
AEROSOLS
AIR
AIR SAMPLERS
DOSIMETRY AND MONITORING
DUCTS
PROBES
RADIATION MONITORING
RADIATION PROTECTION
RADIOACTIVE MATERIALS MONITORING AND TRANSPORT
RADIONUCLIDE MIGRATION
SAMPLING
STACKS
US EPA