|
PHOENIX (The Associated Press) - Jan 21
A shut-down reactor at the nation's largest nuclear plant has been restarted, but the unit could operate at reduced power levels for weeks as utility officials explore solutions to a vibrating coolant pipe. The reactor was restarted Friday, although crews failed to find a quick fix. Plant operators say Palo Verde can operate safely at reduced power levels until the problem is fixed. The other two reactors at the plant remain at full power. Palo Verde, about 50 miles west of downtown Phoenix, supplies electricity to about 4 million customers in Arizona, New Mexico, Texas and California. Arizona Public Service, which owns 29.5 percent of the plant and operates it for a consortium of utility companies in four states, has known about the vibrations since 2001, but the problem became more pronounced after the utility installed new steam generators this fall during the reactor's scheduled refueling. The utility detected the increased rattle and hum after restarting the reactor before Christmas. After taking the reactor out of service Tuesday, the utility attempted to weigh down the pipe, a fix that proved unsuccessful. Now, the utility has identified other potential short-term remedies, including installation of hydraulic shock absorbers, a dampener or clamps and springs that would offset the vibrations. A permanent fix could include relocating a part on the shutdown cooling line. Such a fix wouldn't be attempted until the reactor receives its next refueling in about 18 months. The loss of power in the reactor shouldn't immediately affect the utility's ability to send electricity to homes and businesses in metropolitan Phoenix. Electricity use is at its lowest this time of year. "The thing we need to be concerned about is the possibility of these problems extending into the summer months when we absolutely need that power to meet Arizona's electricity needs," said Kris Mayes, a member of the Arizona Corporation Commission, which regulates electric utilities. Palo Verde has been among the nation's top performing plants since it opened in 1986. Its three reactors can produce nearly 4,000 megawatts of electricity. The plant has experienced numerous outages over the past two years that have resulted in more than a dozen shutdowns. Most recently, two operating reactors at the plant were shut down in October after regulators raised concerns about the emergency cooling system design. The plant was restarted a week later after a review. ___ Information from: The Arizona Republic, http://www.azcentral.com |