One-third of U.S. reactors to shut down for refueling as demand ebbs


About one-third of U.S. nuclear power plants will close this fall for refueling, the most in nine years, as operators take advantage of a drop in electricity demand to carry out maintenance.

Thirty of the nation’s 99 reactors, representing 31 percent of the fleet’s power supply, are expected to shut down through November, according to Michael Rennhack, who heads up That matches the record for autumn set in 2006, data from the Nuclear Regulatory Commission shows.

Lower nuclear output is helping drive up wholesale power prices in the largest U.S. grid and may boost reliance on natural gas-fired generators. Reactors accounted for 19 percent of electricity generation in June, according to the U.S. Energy Information Administration. They typically go offline every 18 to 24 months in the spring or the fall when moderate temperatures ease demand for electricity for cooling or heating.

“At a fundamental level, this is bullish for pricing, because the nukes operate at a very cheap price,” Adam Jordan, a Boston-based energy analyst for Genscape Inc., said by phone last week.

Shutdowns include the 1,403-megawatt unit 2 at Pinnacle West Capital Corp.’s Palo Verde plant outside of Phoenix, one of the largest in the U.S., according to Rennhack, who provides analysis of refueling shutdowns for workers in the industry and said he gets his information from utilities. A subsidiary of Pinnacle West confirmed the planned shutdown.

The reactor shutdowns come after the fleet saw fewer outages during the summer amid higher plant performance and fewer modifications to increase capacity, the EIA said in a September report. A 1,000-megawatt reactor has enough power to meet the demands of 720,000 households, according to the Nuclear Energy Institute, an advocate for the industry.

The increase in shutdowns comes as more power plants are nearing the end of their fuel cycles, said Rennhack. “You run it as long as you can and when you get to the end of the fuel-burn cycle, you have to shut it down,” he said. “For the most part, there is not a lot of wiggle room” on timing.

The NRC’s Region II, which extends from Virginia to Florida, will see the most closures, with 10 reactors capable of supplying 10,798 megawatts set to shut, according to data from Tennessee Valley Authority’s 1,270-megawatt Watts Bar 1 plant, about 100 km outside of Knoxville, Tennessee, which began refueling Sept. 21, is the largest of those slated to go offline there.

The NRC’s Region IV, covering the western half of the lower 48 states, will see the second-most outages with six reactors, capable of producing 7,274 megawatts, to close. Most of the outages will start in October, with 16 reactors supplying 16,187 megawatts of electricity to shutter, based on Rennhack’s data.

Eighteen reactors, capable of producing 19,634 megawatts, have already shut down to replace fuel rods this season, according to Bloomberg data.

The impact on power prices may be limited as demand for electricity falters with the more moderate temperatures, Genscape’s Jordan said.

Gas-fired power plants may increase electricity supplies in the wake of the nuclear outages. Average gas deliveries to power plants since the beginning of September have jumped 7.4 percent from the same period a year ago to 27.1 billion cubic feet a day, according to LCI Energy Insight in El Paso, Texas.