Spatiotemporal Distribution of {sup 241}Am in the Vicinity of the Waste Isolation Pilot Plant - 19543
- U.S. Department of Energy, 4021 National Parks Highway, Carlsbad NM 88221 (United States)
- Carlsbad Environmental Monitoring and Research Center, 1400 University Drive, Carlsbad, NM 88220 (United States)
Environmental monitoring around nuclear facilities is essential for characterizing the baseline conditions that are critical for identifying releases and quantifying their effects, should they occur, and for assessing post-closure performance. The spatiotemporal distribution and transport behavior of {sup 241}Am in the vicinity of a deep geologic repository for transuranic waste were assessed using data spanning the pre-operational phase to the present, including an accidental radionuclide release in 2014. The {sup 241}Am background values of 0.027±0.109 μBq/m{sup 3} (aerosols), and 0.061±0.065 Bq/kg (soil), as well as the {sup 241}Am/{sup 239+240}Pu ratios of 0.41±0.06 (aerosols) and 0.38±0.04 (soil), are similar to global fallout values. Pre-operations concentrations of {sup 241}Am show a strong seasonal dependence, attributed to resuspension of soils contaminated by global fallout, with no contribution from the upwind Project Gnome site ({sup 241}Am/{sup 239+240}Pu =0.24±0.08). During the 2014 accidental release, aerosol concentrations of {sup 241}Am briefly increased to 115.2 μBq/m{sup 3} at an onsite monitoring station, and 81.4 μBq/m{sup 3} at a station ∼1 km downwind of the exhaust shaft, changing the {sup 241}Am/{sup 239+240}Pu from ∼0.37 to ∼10. However, some four years later, conditions have returned to background. Almost 90% of the {sup 241}Am inventory is the 0-5 cm soil layer and there is no evidence of concentrations above regulatory standards, or that can be attributed to waste disposal operations. (authors)
- Research Organization:
- WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
- OSTI ID:
- 23005402
- Report Number(s):
- INIS-US--21-WM-19543
- Country of Publication:
- United States
- Language:
- English
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