Methods Used for Qualification of Sampling Location on a Nuclear Stack

Jeremy Hawk, Idaho State University

Emissions from exhaust stacks at nuclear facilities are required to be monitored for radionuclides.  American National Standard Institute and Health Physics Society standard N13.1-1999 gives the criteria for selection of the sampling location.  The criteria includes requirements for degree of cyclonic flow, velocity profile, gas distribution and aerosol particle distribution within the stack.  ANSI/HPS N13.1-1999 references 40 CFR 60 Appendix A, Method 1 for methodologies to be used during sampling location qualification.  The degree of cyclonic flow and velocity profile are determined using an s-type Pitot tube.  Distributions of gas and aerosol particles are tested by removing samples from the stack using simple probes. Samples are processed in the laboratory.  Gas concentration is determined with mass spectroscopy.  Aerosol particle concentration is determined through the use of cascade impactors.