APS to Fix Reactor Immediately
New timetable likely to cost less
By Ken Alltucker
The Arizona Republic, AZ
March 25, 2006
One of three reactors at the Palo Verde Nuclear Generating Station will remain shut down for several more weeks as crews attempt to fix a vibrating pipe that has reduced the nuclear plant's electricity output since December.
Arizona Public Service Co., the plant's operator, said late Friday that it would repair Unit 1 immediately by relocating a key valve instead or waiting until June to tackle the planned repair.
The Phoenix-based utility expects its new repair schedule will increase the odds the triple-reactor plant will return to full power this summer, when the Valley's peak electricity demand arrives.
The new timetable also should cost less money. APS said Friday that it now expects Unit 1's reduced output will cost $46 million after taxes to buy fuel and power to replace the lost electricity. APS earlier estimated the June repairs would cost $58 million after taxes.
Nevertheless, utility customers will be asked to pick up the tab through higher electricity bills.
"The fact is, we are going to get it done sooner and it will cost customers less," APS spokesman Jim McDonald said.
APS did not pinpoint the reason for its repair schedule change, other than to say that tests performed last week identified "non-standard operating conditions that could impact operations."
Unit 1's electricity output has ranged from 25 to 32 percent of capacity since the utility discovered the vibrating pipe in late December.
The other two reactors at Palo Verde, the nation's largest nuclear-power plant and a significant source of electricity for the Southwest, remain at full power.
APS attempted one repair and studied two other temporary fixes at Unit 1 before deciding this month that the best approach would be to shut down the reactor and relocate a key valve on the unit's emergency shutdown line.
The utility closed Unit 1 last weekend to conduct tests and other preparatory work for the planned June repair. But those tests showed that the reactor's vibrating pipe had the potential to exceed safety limits established in the plant's license issued by the U.S. Nuclear Regulatory Commission.
In addition to relocating the valve, APS said it would complete other repairs, conduct more inspections and gather more evidence to investigate the root cause of the vibrations. The utility expects all necessary repairs will be completed by the beginning of summer.
State regulators who have monitored Palo Verde's performance and its impact on electricity bills said the quicker repairs are a better approach.
"They decided just to tend to it all right now, and I can't second-guess that," Arizona Corporation Commission Chairman Jeff Hatch-Miller said. "They indicated this will save money in terms of purchased power."
Although the plant has operated with a consistent record over much of the past decade, reactors have been shut down 19 times since February 2004 because of worn equipment and design, maintenance and other problems.
APS wants the Corporation Commission to allow it to increase electricity bills to recover $44.6 million related to Palo Verde outages last year. APS is expected to seek money from ratepayers at a later date due to Unit 1's troubles.
APS is allowed to recover 90 percent of prudently incurred fuel and replacement power costs under state- approved guidelines.
Even though the current outage is expected to last longer than five weeks, APS estimates it will be able to secure replacement electricity at a cheaper rate during the spring. Summer electricity costs are typically higher because of increased demand.
APS also said its other power plants are operating at a higher capacity, which also has saved money.
Reach the reporter at ken.alltucker@arizonarepublic.com or (602) 444-8285.
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