Power line behind failure
Kelley Beierschmitt, director of nuclear operations at Oak Ridge National Laboratory, said the problem was not in a safety-related system. However, the electrical line did affect systems that control motor operations and maintain consistent power levels at the 85-megawatt research reactor, he said.
The problem was detected at about 9 p.m. June 21 when control room operators got a warning light indicating a relay failure, Beierschmitt said. A subsequent series of checks confirmed the problem, he said.
The electrical line was replaced over the weekend, and restart testing was being done today, Beierschmitt said. Lab officials have restarted the research reactor, he said.
Beierschmitt said the electrical line was at least 20 years old, and that probably was the reason for the failure. The laboratory is gradually replacing old parts and systems at the research reactor, which was built in the 1960s.
The unplanned shutdown occurred six days before the reactor's regular outage for refueling and maintenance, Beierschmitt said. So the plan is to operate it for the rest of this week to complete the regular fuel cycle and then take it down again for refueling, he said.
The problem shouldn't affect the reactor's rest-of-the-year schedule for research and isotope production, he said.
Related News

Why Fort Frances wants to build an integrated microgrid to deliver its electricity
TORONTO - When the power goes out in Fort Frances, Ont., the community may be left in the dark for hours.
The hydro system's unreliability — caused by its location on the provincial power grid — has prompted the town to seek a creative solution: its own self-contained electricity grid with its own source of power, known as a microgrid.
Located more than 340 kilometres west of Thunder Bay, Ont., on the border of Minnesota, Fort Frances gets its power from a single supply point on Ontario's grid.
"Sometimes, it's inevitable that we have to have like a six- to eight-hour power outage…