It was initially believed to be triggered by a small fire, but federal officials now say the Sunday night alarm at a waste processing center in west Oak Ridge was set off by smoke.
A ventilation system shut off when the power went out during a thunderstorm between 5 and 6 p.m. Sunday, and that caused a heater at the Transuranic Waste Processing Center to overheat, said Laura Wilkerson, federal project director in the U.S. Department of Energyâ€™s Oak Ridge Office.
Wilkerson said the heater in Room 327 in Building 7880 is used to help control humidity in the ventilation system. When the ventilation system shut off, the heaterâ€™s insulation and electrical wiring heated up and generated smoke, setting off the fire alarm.
The buildingâ€™s sprinkler system activated, and the Oak Ridge National Laboratory Fire Department responded, Wilkerson said. The waste processing center, which is off Highway 95 south of Bethel Valley Road, is not part of ORNL, but it receives fire protection from the lab.
An alert was declared at 11:45 p.m. Sunday, and the emergency response was terminated at 4:46 a.m. Monday.
Wilkerson said Room 327 houses the heater and piping equipment for the ventilation system. The building itself is used to process and repackage transuranic waste being moved from ORNL to DOEâ€™s Waste Isolation Pilot Plant near Carlsbad, N.M.
No waste is processed or stored in Room 327, and there were no injuries or radiation exposure or contamination during Sunday nightâ€™s event, Wilkerson said.
On Tuesday, she said the employees scheduled for work on Monday reported to work, but they did not conduct any waste processing activities. Instead, they were cleaning up water from the sprinkler system and assessing damage to that area of the building. Wilkerson said the water cleanup could be complete Tuesday, but an incident assessment and corrective work could take a few days.
Wilkerson said the Transuranic, or TRU, Waste Processing Center treats legacy transuranic waste that has been in storage for many years at ORNL. That includes lab equipment or materials from research and development at ORNL and personal protective equipment. Some of the radioactive materials are handled remotely and others in glove boxes.
Construction on the center was completed in 2003. Itâ€™s operated by a contractor, Wastren Advantage Inc., and the work is overseen by officials at DOEâ€™s Oak Ridge Office.
Transuranic waste contains manmade elements heavier than uranium, such as plutonium, hence the name â€œtransâ€ or â€œbeyondâ€ uranium, the Oak Ridge Office says on theÂ Transuranic Waste Processing website.Â Transuranic waste material is generally associated with the human manipulation of fissionable material dating back to the Manhattan Project through today, and it primarily consists of clothing, tools, rags, residues, soil, and debris.