Evaluating Radionuclide Air Emission Stack Sampling Systems
- Univ. of Washington, Seattle, WA (United States)
The Pacific Northwest National Laboratory (PNNL) operates a number of research and development (R&D) facilities for the U.S. Department of Energy at the Hanford Site, Washington. These facilities are subject to Clean Air Act regulations that require sampling of radionuclide air emissions from some of these facilities. A revision to an American National Standards Institute (ANSI) standard on sampling radioactive air emissions has recently been incorporated into federal and state regulations and a re-evaluation of affected facilities is being performed to determine the impact. The revised standard requires a well-mixed sampling location that must be demonstrated through tests specified in the standard. It also carries a number of maintenance requirements, including inspections and cleaning of the sampling system. Evaluations were performed in 2000 – 2002 on two PNNL facilities to determine the operational and design impacts of the new requirements. The evaluation included inspection and cleaning maintenance activities plus testing to determine if the current sampling locations meet criteria in the revised standard. Results show a wide range of complexity in inspection and cleaning activities depending on accessibility of the system, ease of removal, and potential impact on building operations (need for outages). As expected, these High Efficiency Particulate Air (HEPA)-filtered systems did not show deposition significant enough to cause concerns with blocking of the nozzle or other parts of the system. The tests for sampling system location in the revised standard also varied in complexity depending on accessibility of the sample site and use of a scale model can alleviate many issues. Previous criteria to locate sampling systems at eight duct diameters downstream and two duct diameters upstream of the nearest disturbances is no guarantee of meeting criteria in the revised standard. A computational fluid dynamics model was helpful in understanding flow and contaminant mixing in an exhaust system and may be useful to identify potential sampling locations in an exhaust system that are likely to meet criteria in the revised standard.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1000182
- Report Number(s):
- PNNL-14138; EY3542401; TRN: US201101%%580
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
POLICY AND ECONOMY
CLEAN AIR ACTS
CLEANING
COMPUTERIZED SIMULATION
DEPOSITION
DUCTS
EFFICIENCY
EVALUATION
EXHAUST SYSTEMS
FLUID MECHANICS
MAINTENANCE
NOZZLES
PARTICULATES
RADIOISOTOPES
REGULATIONS
REMOVAL
SAMPLING
SCALE MODELS
TESTING
radionuclide air emission
stack sampling system