U.S. nuclear-power generation fell for the first time in three days after a Texas reactor was shut because of a transformer fire.
Output slid 0.1 percent from yesterday to 93,176 megawatts, or 91 percent of capacity, according to U.S. Nuclear Regulatory Commission data compiled by Bloomberg. Output was 3.2 percent less than a year ago with seven of 104 nuclear reactors offline.
Unit 2 of the South Texas Project Electric Generating Station declared an unusual event, the lowest-level emergency category, “due to a main transformer fire” at 4:40 p.m. local time yesterday, according to the commission’s event notification report today. The reactor tripped offline following the loss of power, it said.
The on-site fire brigade extinguished the flames, emergency diesel generators were started and the reactor is stable, the plant reported. The emergency event notice ended at 7:47 p.m. local time and there were no injuries, it said.
“We are in the process of going through a thorough investigation looking at the damage and what the scope of work will be to get the unit back up,” said Buddy Eller, a spokesman at the plant 80 miles (129 kilometers) southwest of Houston. “We should have a better feel in a few days.”
The 1,410-megawatt unit was operating at 48 percent of capacity early yesterday, NRC data show. Eller said that Unit 1, which has the same capacity, is operating at 100 percent.
“We have sufficient generation scheduled to serve expected demands and maintain our preferred operating reserve margin today,” Robbie Searcy, a spokeswoman in Austin for the Electric Reliability Council of Texas, which manages the state’s main power grid, said in an e-mail today.
NRG Energy Inc. has a 44 percent ownership in the station while municipally owned CPS Energy has a 40 percent stake and Austin Energy has 16 percent.
Entergy Corp. increased output at the 1,297-megawatt Grand Gulf 1 reactor in Port Gibson, Mississippi, to 56 percent of capacity from 9 percent yesterday. The unit was restarted yesterday after being shut Jan. 5.
Output in the NRC’s Region 4, which includes Texas, declined 0.9 percent to 17,239 megawatts, or 72 percent of capacity. Nuclear generation was little changed elsewhere.
Reactor maintenance shutdowns, usually undertaken in the U.S. spring or fall when energy use is lowest, may increase consumption of natural gas and coal to generate electricity. The average refueling down time was 43 days in 2011, according to the Nuclear Energy Institute.