PNNL

Abstract

The Pacific Northwest National Laboratory (PNNL) conducted testing at two research and development (R&D) facilities where continuous sampling for radioactive air emissions is required. The testing was conducted to determine whether sampling system locations would meet the criteria for uniform air velocity and contaminant concentration in the American National Standard Institute (ANSI) standard, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stacks and Ducts of Nuclear Facilities (ANSI/HPS N13.1-1999). The standard is a revision of the 1969 version that the facilities have been required to meet. The 1999 revision is drastically different from the 1969 version in its approach, requiring a well-mixed sampling location that must be demonstrated through performance tests that are specified in the standard. Testing at the 331 Facility was performed on the existing stack at the current sampling location; a scale model was built and used in place of the 325 Facility. Although both facilities’ sampling sites were compliant with the 1969 standard, only the 325 Facility met the criteria of the revised standard.