ANSI 1999 Compliance Testing at ORNL

L.L. Smith1 and J.L. Alvarez2 (1Rad NESHAP Program Manager, ORNL; 2Contractor, Auxier & Associates, Inc., PhD, CHP)

The final amendment to 40 Code of Federal Regulations (CFR) Part 61, Subpart H, promulgated September 9, 2002, requires the use of the ANSI/HPS N13.1-1999 standard for "any newly constructed source and any source undergoing a modification that would result in an effective dose equivalent (EDE) to any member of the public greater than 1% of the standard." Emissions from existing point sources resulting in an EDE greater than 1% of the standard can continue to be directly monitored following the guidance presented in ANSI N13.1-1969. As part of a plan to revitalize the Oak Ridge National Laboratory, some facilities within the laboratory will be upgraded, other facilities will be decommissioned, and some processes will be moved to better locations in anticipation of research needs over the next 10 to 20 years. In order to determine if these anticipated modifications and changes would require upgrades to two existing major radiological exhaust stacks, testing was done as prescribed in section 5 of ANSI/HPS N13.1-1999 to determine if the existing sampling locations qualified to meet the standard. Existing velocity profile data showed that the average cyclonic flow angle of the exhaust streams of both stacks at their respective sampling locations was well below the 20-degree criteria of acceptability. In addition, the coefficient of variation of the velocity measurements across both traverses of the stack cross section at the sampling location was within 20%, demonstrating that a uniform velocity profile existed. Sulfur hexafluoride was used as the tracer gas to determine if the gaseous contaminant concentration profile was uniform and it was also found that the coefficient of variation of the concentration measurements were within the criteria of acceptability of 20%. Finally, soy bean oil was used in an aerosol generator to produce aerosol particles to determine if the particulate contaminant concentration profile was uniform.

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