WASHINGTON — The Department of Energy has launched investigations into two incidents over the past year where workers at the Nevada National Security Site were exposed to potential contamination while conducting nuclear weapons activities.
The episodes took place on June 16, 2014, and Oct. 21, 2014, at the National Criticality Experiments Research Center, the laboratory where the government maintains a substantial stockpile of nuclear material used for research and training.
The department is looking into the circumstances surrounding “losses of contamination control of highly enriched uranium” at the lab, according to Steven Simonson, director of the DOE Office of Enforcement.
Simonson announced the probe in a June 4 letter to Charles McMillan, the director of the Los Alamos National Laboratory. The New Mexico lab operates the research facility within the high-security Device Assembly Facility on the sprawling Nevada range.
DOE officials did not detail the circumstances surrounding the incidents nor the number of workers who may have been exposed. Los Alamos reported the incidents in January, according to Simonson.
Simonson said National Security Technologies, or NSTec, the management contractor at the Nevada National Security Site, will also be investigated for its role in the incidents.
Thomas Metzger, a spokesman for the National Nuclear Security Administration that oversees the government’s weapons laboratories and what used to be called the Nevada Test Site, said the investigations are ongoing. He had no further information.
In a statement, Los Alamos said that bioassays showed “the levels of exposure were extremely small and health risks essentially zero for those affected by the contamination event.
“There was no contamination spread outside the facility that houses NCERC… and there was no risk to the public or environment.”
The laboratory, which operated at Los Alamos before it was relocated to Nevada for security purposes and reopened in 2011, is utilized for a broad array of nuclear safety research and training programs. Researchers use a variety of nuclear materials in the work, ranging from small neutron-emitting sources to quantities of uranium and plutonium, according to the security agency.
The incidents that prompted the investigation were the latest disclosed missteps by Los Alamos and other outposts in the weapons complex that have come under close scrutiny within DOE and on Capitol Hill.
In May, the Energy Department proposed to fine the operator of the Los Alamos National Laboratory $247,500 after it lost track of classified material that was supposed to have been shipped to the Nevada National Security Site in 2007, but never arrived. The mistake was not detected until five years later.
The New Mexico laboratory also has been faulted in the 2014 release of radiation from the Waste Isolation Pilot Plant that contaminated nearly two dozen workers with low levels of radiation and forced the nuclear waste site to close.
Investigations uncovered violations at the laboratory in how transuranic waste destined for WIPP was packaged and managed.
In its statement on the Nevada incidents, Los Alamos said it was working with NNSA and NSTec “in a formal process to review and confirm that new procedures and controls are in place and functioning properly.”
“The laboratory takes this event very seriously and will do everything reasonable to prevent a similar event in the future,” according to the statement.