Palo Verde shuts down reactor for repairs

One of the three reactors at Palo Verde Nuclear Generating Station shut down Friday to fix a turbine cooling-system leak, reducing output during what was shaping up to be a banner year at the facility.

“The health and safety of the public is not affected,” spokeswoman Betty Dayyo said. “This is on the non-nuclear side of the plant.”

But the fix could take several weeks, she said, leaving Arizona Public Service Co. and the plant's other owners buying replacement power from coal or natural-gas power plants.

Utility customers, including those of Salt River Project, will pay the higher cost of electricity for that replacement power unless regulators determine the outage was avoidable, in which case APS would be on the hook for the cost.

“This will be examined in the APS rate case and will be scrutinized,” Corporation Commissioner Kris Mayes said.

APS Chief Nuclear Officer Randy Edington said the utility was not forced to shut the reactor down to repair the small leak of hydrogen used to cool the freight-train sized turbine. But the low energy demand in November provides a good opportunity to make the fix.

Edington has known about the problem in Unit 2 for more than 30 days, he said, but wanted to wait until Unit 1 was brought back online last week after a refueling shutdown, which each reactor needs every 18 months.

“We've been monitoring it and are taking the opportunity to take it off before the Christmas holiday,” he said. “We didn't want it to go down during Christmas, or into the next refueling outage (a single-reactor shutdown) scheduled in spring.”

The plant only had three unexpected outages this year before Friday, compared with 13 times last year and 11 times in both 2005 and 2006 when output had to be reduced at least 50 percent.

Edington still could achieve an 84 percent capacity factor for the plant this year, although the outage will prevent the 86.5 percent he was anticipating. The capacity factor has been in the 70s the past three years, and hit a record 94.4 percent in 2002.

“Obviously, we would prefer we not have a problem,” spokesman Jim McDonald said. “But this doesn't make it any less of a good year. The fact is that Palo Verde has emerged from a difficult time with a tremendous rapport with the (Nuclear Regulatory Commission), with an operating philosophy that puts safety clearly ahead of production.”

The plant has seven owners who get a set amount of the total energy coming out of the reactors, regardless how many are online. The owners include APS (29.1 percent), SRP (17.5 percent), Southern California Edison (15.8 percent), El Paso Electric (15.8 percent), PNM Resources (10.2 percent), Southern California Public Power Authority (5.9 percent), and Los Angeles Department of Water and Power (5.7 percent).