Generic effluent monitoring system certification for AP-40 exhauster stack

Tests were conducted to verify that the Generic Effluent Monitoring System (GEMS), as applied to the AP-40 exhauster stack, meets all applicable regulatory performance criteria for air sampling systems at nuclear facilities. These performance criteria address both the suitability of the air sampling probe location and the transport of the sample to the collection devices. The criteria covering air sampling probe location ensure that the contaminants in the stack are well mixed with the airflow at the probe location such that the extracted sample represents the whole. The sample transport criteria ensure that the sampled contaminants are quantitatively delivered to the collection device. The specific performance criteria are described in detail in the report. The tests demonstrated that the GEMS/AP-40 system meets all applicable performance criteria. The contaminant mixing tests were conducted by Pacific Northwest National Laboratory (PNNL) at the wind tunnel facility, 331-H Building, using a mockup of the actual stack. The particle sample transport tests were conducted by PNNL at the Numatec Hanford Company`s 305 Building. The AP-40 stack is typical of several 10-in. diameter stacks that discharge the filtered ventilation air from tank farms at the U.S. Department of Energy`s Hanford Site in Richland, Washington. The GEMS design features a probe with a single shrouded sampling nozzle, a sample delivery line, and sample collection system. The collection system includes a filter holder to collect the sample of record and an in-line detector head and filter for monitoring beta radiation-emitting particles. Unrelated to the performance criteria, it was found that the record sample filter holder exhibited symptoms of sample bypass around the particle collection filter. This filter holder should either be modified or replaced with a different type. 10 refs., 8 figs., 6 tabs