1. Mitigation Dust Loading REMP Air Samplers

2. Dust Loading Definition / Symptoms Accumulation of loose particulate matter on air sampling particulate filter media Reduction in air sampler flow rate due to accumulation of material on the air sampler surface Increase in back pressure across air sample filter media

3. Why it’s a Problem Dust loaded REMP air samples may not be representative Chronically dust loaded air sampling equipment may be more prone to mechanical failure

4. REMP Air Sampler Dust Loading at SONGS REMP air sampling apparatus consisted of sample line feed from the exterior of the “doghouse” style enclosure to and in-line type sample cartridge Observed loose particulate matter on most REMP air sampler Occasional episodes of reduced flow and increased media back pressure ~ 5% of samples dust loaded

5. Proposed Remedy Change sampling method from in-line type to open face sample method Sampling method recommended by subject matter experts DOE reference

6. Comparison of Open Face Sampling to In-Line Sampling Method at SONGS Two (2) auxiliary open face samplers were installed at the same location as two REMP stations Duplicate data collected for 15 months

7. Data and Observations Open face sample cartridge samplers had no observed loose particulate matter Most in-line type samples had loose particulate matter on the filter media 15 month in-line type sample gross beta data was about 7% higher than the open face gross beta data About 5% of the in-line samples were dust loaded (increased back pressure and /or reduced flow) Open face samplers had no observed occurrences of dust loading during the study period