St. Lucie Nuclear Power Plant Unit 1 Manually Shut Down After Three Control Rods Dropped into the Core

According to an event notification submitted to the U.S. Nuclear Regulatory Commission (NRC), Unit 1 of the St. Lucie Nuclear Power Plant, located on Hutchinson Island, Florida, USA, experienced a manual reactor shutdown at 9:47 a.m. Eastern Time on August 13, 2026. At the time of the event, the unit was in Mode 1 and operating at 100% power. The shutdown was caused by three control rods dropping into the reactor core.

The U.S. Nuclear Regulatory Commission classified the event as a non-emergency. The licensee stated that the shutdown was completed in accordance with procedures, all systems responded normally after the shutdown, and operators subsequently stabilized the unit in Mode 3, i.e., hot standby condition. Decay heat was removed by diverting steam to the main condenser via turbine bypass valves and the main feedwater system. Unit 2 of the St. Lucie Nuclear Power Plant was not affected, and the NRC resident inspector has been notified.

Control rods are made of neutron-absorbing materials and are important components for power regulation and shutdown control of nuclear reactors. When control rods are inserted into the core, they absorb neutrons and reduce the rate of the nuclear fission chain reaction; when sufficient insertion is achieved, the reactor can be shut down.

Florida Power & Light Company (FPL), the operator of the St. Lucie Nuclear Power Plant, described the situation as an equipment issue. Its parent company, NextEra Energy, stated that on-site personnel safely shut down Unit 1 and addressed the related issues in accordance with strict procedures, and that the event posed no danger to personnel and did not affect customer power supply. The company stated that Unit 1 resumed operation on August 16 and reached 100% generating power.

The St. Lucie Nuclear Power Plant has two units, with Unit 1 entering commercial operation in 1976 and Unit 2 in 1983. The plant has a generating capacity of approximately 2,000 megawatts, accounting for about 11% of Florida Power & Light Company's total generation. In April of this year, the U.S. Nuclear Regulatory Commission approved the renewal of the operating license for Unit 1 of the St. Lucie Nuclear Power Plant through 2056, and for Unit 2 through 2063.