Resuspension Consequence Assessment of the WIPP Release

Area of Science:

• Environmental Science
• Radiological Health Physics
• Nuclear Waste Management

Background:

• A radiological material release occurred at the Waste Isolation Pilot Plant (WIPP) on February 14, 2014, due to improper waste packaging.
• The incident involved a chemical reaction that released americium-241 (241Am) as airborne contamination within the WIPP underground repository.

Purpose of the Study:

• To assess the long-term, off-site radiation doses resulting from the WIPP radiological release.
• To determine the extent of ground deposition and potential inhalation pathway doses for off-site locations.

Main Methods:

• Validated plume modeling was used to determine initial ground deposition and ensure releases were below regulatory limits.
• The health physics code HOTSPOT was employed to generate air source terms and analyze the contamination plume.
• Dose calculations for off-site locations were performed by summing grid "kernels" to assess inhalation pathway exposure.

Main Results:

• Ground deposition was modeled, and off-site doses were calculated using the HOTSPOT code.
• Lifetime integrated total effective dose equivalents (TEDEs) were found to be on the order of millisievert or less, considered radiologically negligible.
• Resuspension of material was analyzed, with upper-bound lifetime doses remaining substantially below average annual background radiation (approx. 3.10 mSv).

Conclusions:

• The radiological release at WIPP posed negligible long-term health risks to off-site populations.
• Conservative dose assessments confirm that the incident's impact was insignificant from a radiobiological perspective.
• The study validates the effectiveness of plume modeling and dose assessment tools in evaluating radiological incidents.