STP Unit 1 returned to service May 15 following a 75-day shutdown for a routine refueling and replacement of the unit's four steam generators. The huge vessels, weighing 500 tons each, use reactor-heated water to convert the water in a separate, sealed system into high pressure steam that spins turbines and generates electricity.

"This massive project succeeded thanks to the hard work of STP's employees and contractors," said Ted Cloninger, vice president of Nuclear Generation. "Virtually all of STP's nearly 1,500 employees worked on the effort directly or in support roles, in addition to their regular duties," Cloninger said. Almost 1,100 contractors were brought in from across the country to help perform about 14,000 plant maintenance and steam generator replacement tasks.

The steam generators were replaced to restore the unit to its original design capability after monitoring and inspections revealed that the material condition of the generators had degraded. This degradation did not pose a safety hazard but would have shortened the plant's designed 40-year life span. STP Unit 1 began operations in 1988.

Westinghouse Electric Company fabricated the new steam generators and assembled them using components supplied by vendors in Japan, Sweden, Spain, Italy and other countries. Bechtel was the prime contractor for installation and implementation. The four steam generators in STP's twin Unit 2 will be replaced in 2002.

STP is owned by Reliant Energy HL&P, Central Power and Light Company, City Public Service of San Antonio, and Austin Energy. The plant is operated by STP Nuclear Operating Company and produces 2,500 megawatts of electricity, enough to serve more than one million homes.