Palo Verde refueling top-performing reactor
Workers in white, protective coveralls and brightly colored hardhats, rubber gloves and booties pass through the heavy steel door of the No. 1 unit at Palo Verde Nuclear Generating Station as the sound of a radiation monitor pings in the background.
The unit just finished its most productive 18-month run since it opened in 1986, and the 11.6 million megawatt-hours of electricity it generated in 2015 made it the most productive nuclear reactor in the world, according to its operator, Arizona Public Service Co. The other two nuclear reactors at Palo Verde are among the biggest competition for those accomplishments.
Combined, the three units 50 miles west of downtown Phoenix produced more electricity in 2015 than any other U.S. power plant, as they have for the past 24 years.
At midnight April 8, the No. 1 reactor shut down so that one-third of its uranium fuel rods could be taken out, placed in a cooling pool, and replaced with fresh rods for another 18-month run.
The reactors are refueled in the spring and fall to ensure they are operating during the summer, when the seven utilities from Texas to California that rely on Palo Verde need it selectricity the most.
During the refueling outages, APS frequently invites media to tour the reactors. Such media access would be impossible while a reactor is running, with high radiation levels inside the 4-foot-thick concrete containment dome.
APS gave a tour to reporters from Sedona, Yuma and metro Phoenix on April 14 to answer questions about the plant and nuclear power in general, giving them a perspective of how the 3,000 workers at the plant spend their days.
The plant isn’t undergoing any major repairs during this outage, which is scheduled to last 30 days, but APS is looking at some major improvements down the road.
One improvement APS is planning is upgrading to digital controls in the next 20 years, said John Cadogan, vice president of engineering.
Reporters were given a tour of one of the control rooms, with wall-to-wall manual switches and buttons forming a semi-oval around the plant operators, clearly revealing its 1980s vintage.
All the new reactors being built in the U.S. today and globally will have more digitized controls, but those built in the 1980s and prior have to refurbish their controls to upgrade them. This will be done incrementally during planned refueling outages, officials said.
“We will start (replacing) the systems that are not as critical,” said Don Vogt, assistant plant manager for Palo Verde Unit 2. “No other reactor has gone all digital.”
Palo Verde’s reactors each received a 40-year license from the Nuclear Regulatory Commission when they opened, and with 20-year extensions granted by the NRC in 2011, they will run until 2045, 2046 and 2047.
Cadogan said the plant is likely to seek additional 20-year extensions for each reactor. With the plant already built and with operations running efficiently, the electricity from Palo Verde is among the least expensive to produce for the owners: APS, Salt River Project, Southern California Edison, El Paso Electric Co., Public Service Co. of New Mexico, Southern California Public Power Authority and the Los Angeles Department of Water and Power.
The Arizona utilities have long-term plans to reduce carbon emissions, which primarily means reducing the amount of coal-fired power plants in their fleet. California utilities are moving entirely away from coal.
Utilities increasingly are relying on natural gas, which is currently cheap and has about half the carbon emissions of coal, but Cadogan said that the move away from fossil fuels increases the importance of nuclear power, which does not emit carbon.