BRIDGMAN, Mich., April 25, 2003 - A massive intrusion of Alewives, a small fish, clogged plant cooling water intake systems Thursday and resulted in plant operators shutting down both units of American Electric Power’s (NYSE:AEP) Cook Nuclear Plant. It is common for the Alewife population along the shoreline to dramatically increase in the spring when the Alewives move to shallow water to spawn, but this sudden large intrusion was uncharacteristic.

All safety systems responded appropriately when both units were manually shutdown at about 3:30 a.m. Thursday. The plant’s Emergency Plan was activated because of a concern with the reduction of available cooling water to essential plant equipment. The four diesel generators, one of the emergency power supply sources, were declared inoperable, but remained available to perform their safety function.

Cooling water flow was restored about two hours after the event, and safety systems were inspected and tested throughout the day. The Emergency Plan was exited at 5:21 a.m. today when full availability of safety systems was verified.

Intake water system screens and strainers are designed to maintain flow to plant cooling water systems, but the systems were overwhelmed by the sudden influx.

"A massive school of fish came through our intake tunnels in a very short period of time around 2 a.m. Thursday,” said John Carlson, Cook’s Environmental Manager. “Fisherman around our intakes and the St. Joseph River have reported detecting inordinately large amounts of small fish in recent days. They are likely looking for warmer water to feed or spawn.“

Mature Alewives range in size from three to six inches. Some populate North American lakes and streams year around, and some migrate from the Atlantic Ocean through the St. Lawrence Seaway.

No decision about return-to-service of the units has been made.