Single point aerosol sampling: Evaluation of mixing and probe performance in a nuclear stack

Journal Article · Mon Jan 01 04:00:00 EST 1996 · Health Physics

DOI:https://doi.org/10.1097/00004032-199601000-00005· OSTI ID:258413

Rodgers, J C; Fairchild, C I; Wood, G O ^[1]; Ortiz, C A; Muyshondt, A ^[2]

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1. Los Alamos National Laboratory, NM (United States)
2. Texas A&M Univ., College Station, TX (United States); and others

Alternative reference methodologies have been developed for sampling of radionuclides from stacks and ducts, which differ from the methods previously required by the United States Environmental Protection Agency. These alternative reference methodologies have recently been approved by the U.S. EPA for use in lieu of the current standard techniques. The standard EPA methods are prescriptive in selection of sampling locations and in design of sampling probes whereas the alternative reference methodologies are performance driven. Tests were conducted in a stack at Los Alamos National Laboratory to demonstrate the efficacy of some aspects of the alternative reference methodologies. Coefficients of variation of velocity, tracer gas, and aerosol particle profiles were determined at three sampling locations. Results showed that numerical criteria placed upon the coefficients of variation by the alternative reference methodologies were met at sampling stations located 9 and 14 stack diameters from the flow entrance, but not at a location that was 1.5 diameters downstream from the inlet. Experiments were conducted to characterize the transmission of 10 {mu}m aerodynamic diameter liquid aerosol particles through three types of sampling probes. The transmission ratio (ratio of aerosol concentration at the probe exit plane to the concentration in the free stream) was 107% for a 113 L min{sup {minus}1} (4-cfm) anistokinetic shrouded probe, but only 20% for an isokinetic probe that follows the existing EPA standard requirements. A specially designed isokinetic probe showed a transmission ratio of 63%. The shrouded probe performance would conform to the alternative reference methodologies criteria; however, the isokinetic probes would not. 13 refs., 9 figs., 1 tab.

• Sponsoring Organization: USDOE
• OSTI ID: 258413
• Journal Information: Health Physics, Journal Name: Health Physics Journal Issue: 1 Vol. 70; ISSN HLTPAO; ISSN 0017-9078
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
DUCTS
LANL
MIXING
PROBES
RADIOACTIVE AEROSOLS
SAMPLING
STACKS