News Releases

Operators at AmerenUE's Callaway Nuclear Plant are shutting the plant down, today, to determine the cause of a valve problem in the non-nuclear part of the plant that is preventing the plant from operating at full power. Since the cause has not yet been determined, AmerenUE officials would not speculate on how long repairs might take. But they emphasize that there is no emergency, and that a similar equipment problem could occur in any other type of steam- powered electric generating plant.

The problem involves one of four valves that control the flow of steam to the turbines that drive the generator to produce electricity. This valve will not open fully, thus reducing the supply of steam to the turbines and preventing the plant from operating at more than 90 percent power.

AmerenUE officials say they have not found any connection between the current valve problem and a shutdown that took place last Friday, May 12, to investigate high vibration alarms on two of the main turbine bearings. Operators discovered the valve problem as they were returning the plant to full service over the weekend after restarting the plant late Friday night. AmerenUE officials add that the restart Friday night was normal.

In 2005, the Callaway Plant was the third largest power producer on the Ameren system\-accounting for 10.3 percent of total generation. Its net generation of 1,190 megawatts is enough to supply 656,000 average homes.

When the plant is out of service, the electricity it normally produces is replaced by other plants. The current outage is not expected to have any impact on customers.

AmerenUE is a subsidiary of St. Louis-based Ameren Corporation. The Ameren companies serve 2.4 million electric customers and nearly one million natural gas customers in a 64,000-square-mile area of Missouri and Illinois.

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