A fire at DTE Energy’s Fermi 2 nuclear power plant on Monday, May 18, prompted a “scram,” the emergency shutdown of the plant’s nuclear fission activity. But DTE officials say the fire was minor and employees and the public were not at any risk from the incident.
According to incident information filed with the federal Nuclear Regulatory Commission, a fire occurred below the Fermi 2 plant’s main generator at about 6 p.m. Monday.
The fire was discovered in an isophase duct. At a nuclear power plant, electricity is generated using a standard three-phase alternating current, or AC system. Isophase, or isolated-phase, ducts refer to an electrical housing system where each of the three individual electrical phases is kept in its own separate, shielded enclosure.
By 6:07 p.m., the reactor was “manually scrammed,” according to the NRC incident report, meaning plant employees undertook an emergency shutdown of the reactor that halts the nuclear fission chain reaction and stops the generation of main heat. The fire was extinguished by 6:10 p.m., according to the report.
The NRC report includes the following information provided to the federal agency by DTE officials:
“Operations responded and stabilized the plant. Reactor water level is being maintained at normal level … Decay heat is being removed by the main steam system to the main condenser using automatic operation of the turbine bypass valves. All control rods inserted into the core.
“Due to the reactor protection system actuation while critical, this event is being reported as a four-hour nonemergency notification per (federal law).”
According to the U.S. Department of Energy, inserting control rods into the core at a nuclear power plant means the operators are adding neutron-absorbing material (like boron, hafnium, or cadmium) into the reactor. This absorbs the neutrons that sustain nuclear fission, which slows down or completely halts the nuclear chain reaction.
DTE Energy Nuclear Communications Manager Stephen Tait provided the Free Press with the following statement:
“Operators at Fermi 2 safely took the plant offline Monday evening following a small fire that was quickly extinguished. The fire occurred in the turbine building, which is on the non-nuclear side of the plant. The plant remains in a safe and stable condition, and at no time was there any risk to the health and safety of the public or our employees.”
DTE will conduct “a thorough evaluation of the event” and complete any necessary repairs before returning the unit to service, Tait said.
Located on the western shores of Lake Erie in Newport in Monroe County, the Fermi 2 Power Plant began commercial operation in 1988. The single-cycle, forced-circulation boiling water reactor generates 1.1 million kilowatts of power, enough electricity to serve a city of about 1 million homes.
Contact Keith Matheny: kmatheny@freepress.com.
This article originally appeared on Detroit Free Press: Fire at DTE Energy’s Fermi 2 nuclear plant leads to temporary shutdown
Reporting by Keith Matheny, Detroit Free Press / Detroit Free Press
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