According to Nuclear Regulatory Commission data, five of the 99 units in the domestic nuclear power fleet were offline early Sept. 14 as some reactors begin their autumn refueling and maintenance outages.
But at least one outage, the DTE Energy Fermi 2 nuclear plant in Michigan, was unplanned. Fermi 2 went offline late Sept. 13 due to a “manual scram” that was initiated in response to a loss of all Turbine Building Closed Cooling Water (TBCCW),” according to an NRC event report.
In addition to Fermi 2, it appears that during the weekend the Tennessee Valley Authority (TVA) Sequoyah 1 facility, Exelon Byron 1 in Illinois, and the Duke Energy McGuire 2 nuclear unit in North Carolina went offline over the weekend.
The NextEra Energy St. Lucie 2 facility in Florida was already offline.
An Exelon spokesperson confirmed that Byron 1 went offline for a planned maintenance outage. The facility operates on an 18-month refueling cycle.
Nuclear plants tend to schedule their refueling and maintenance activity during the spring and fall shoulder seasons when electric demand tends to be lower.