The largest nuclear power facility in the U.S. issued an unusual event declaration over the weekend after workers reported feeling an earthquake at the Palo Verde plant near Phoenix.
The 5.2 magnitude quake near Lordsburg, N.M., was not strong enough to trip safety systems at the plant, according to a report to the Nuclear Regulatory Commission. Nonetheless, operators issued the NRC's lowest level of emergency declaration at 10:17 p.m. Saturday while crews conducted a walk down of the plant. They reported no activations of engineered safety features or damage to equipment. The emergency declaration was cancelled at 1:12 a.m. the following morning, and the plant's reactors operated a full power throughout.
Palo Verde can generate more than 4,000 megawatts using three Combustion Engineering System 80 reactors completed in the mid-1980s. They are owned jointly by seven utilities in Arizona, California, New Mexico and Texas, with Arizona Public Service operating the plant and holding the largest ownership stake at 29.1 percent.