A significant amount of material was ejected when four 55-gallon drums of radioactive waste blew their lids off during an April 11 incident at the Idaho National Laboratory, Fluor Idaho said in a recent report.
“A significant portion” of the potential 220 gallons of repackaged waste sludge were found afterward scattered on the floor and on other surfaces within Airlock 5 of the Accelerated Retrieval Project 5 facility, the Idaho Cleanup Project contractor reported.
This first monthly report to the Idaho Department of Environmental Quality, which covers April 27 through May 24, said early tests suggest there is little chance of this spilled material reheating and endangering cleanup personnel. The material has been exposed to air since April 11, the report notes.
The document also said most cleanup of the floor around the breached drums should be done this month. But it is not yet known what caused the drums to overheat, and no date has been set for resuming repackaging of waste for off-site shipment, possibly to the Waste Isolation Pilot Plant (WIPP) in New Mexico.
The report does offer more details on the event.
A fire crew responded to a smoke alarm at the facility around 10:35 p.m. local time on April 11 and discovered a smoldering drum with its lid resting about 10 meters away. The drum’s temperature at the time was roughly 300 degrees Fahrenheit, equipment indicated.
After attempting to extinguish the smoldering drum, the crew left the building. Shortly after midnight a loud “bang or boom,” was heard outside, the report said. All personnel were moved back to 100 meters from the building. Another loud noise was heard inside the structure around 3:28 a.m. on April 12.
In the first week after the episode, filters from continuous air monitors, along with other samples from the building, were sent to the Savannah River National Laboratory in South Carolina and the Southwest Research Institute in Texas for chemical and radiological tests. In the weeks since then, samples of the material ejected from the drums, along with samples remaining in the containers, were sent to the two sites for further analysis.
Early testing suggests the material is not subject to spontaneous combustion.
In a Friday email, Fluor Idaho spokesman Erik Simpson said the affected drums are still in the airlock and will be overpacked in preparation for future processing. The waste will be ultimately placed in different containers with new lids.
