A wafer of plutonium-239 fell to the floor and broke at a National Institute of Standards and Technology facility in Maryland Friday afternoon.
The material broke in half when dropped from its holder following neutron irradiation in the NIST's Research Reactor Test Facility, according to a report filed with the Nuclear Regulatory Commission and published Monday. The 60 nanocurie Pu-239 source was safely retrieved and moved to a safe. Subsequent instrument and swipe surveys around the room showed a single spot of alpha contamination where the material fell. It was measured at 200 CPM and was carefully decontaminated. Personnel working nearby were evaluated and found to be clear of contamination, with the exception of two people whose nasal swipes showed traces of alpha contamination (0.17 DMP each) that the lab calculated would not result in doses exceeding 10 millirem.
NIST conducts a range of neutron research at the facility in Gaithersburg, Md. The reactor was placed into service in 1967 and relicensed by the NRC in 2009.