Air sampling at a transuranic waste repository in New Mexico revealed a slight increase in radioactive material last week, which the Department of Energy believes was left over from an earlier release Feb. 14.
On March 11, a sample from the ventilation exhaust of the Waste Isolation Pilot Plant detected americium at 61 disintegrations per minute, or just over 1 becquerel. The site does not anticipate any related health or environmental impacts. A DOE release announcing the results Tuesday said, "This is expected, given the amount of contamination captured by the WIPP ventilation system during the Feb. 14 radiation release event. Engineers believe the contamination was from previous deposits on the inner surface of the exhaust ductwork."
The earlier incident resulted in elevated levels of radiation at multiple points around the plant that then tapered off. It followed a truck fire at the site nine days earlier and remains under investigation. Seventeen of 135 WIPP employees tested to date received small internal radiation doses following the first release.