BRIDGMAN, Mich., June 7, 2000 – American Electric Power's (NYSE: AEP) Cook Nuclear Plant Unit 2 entered Mode 4, the reactor coolant system heat-up phase of the plant's return to service, Tuesday evening, according to company officials. “With this milestone passed, we will move forward with a safe and deliberate start-up of Cook’s Unit 2,” said Bob Powers, AEP senior vice president - nuclear generation. “We have completed all of the restart modifications and pre-startup testing and closed out all the NRC checklist items.” Entry into Mode 4, or reactor hot shutdown, requires safety systems to be fully checked and operational. Plant operators are heating the reactor coolant system to full temperature and pressure in preparation for start-up and operation of the reactor. On Monday, at the monthly public restart update meeting with the Nuclear Regulatory Commission (NRC), AEP asked the NRC to begin the restart authorization process and concur that the unit is ready to restart. The NRC is expected to make a public notification when a decision on restart is made. Plant officials will continue to work through the start-up checklist, which consists primarily of safety system functional checks, while the unit heats up. AEP will not start-up the reactor until concurrence to restart is received from the NRC. “Since the plant has not been operational in some time, there’s the possibility that minor equipment maintenance or modification issues could arise during the heat up and early days after returning to service. But we still expect the unit to be at full power for the peak summer demand,” said Powers. Once the reactor begins operation and reaches about 9 percent power, the output of the generator will be connected to the AEP transmission grid. An ascension to full power includes several hold points for additional system checks and tests, and is expected to take an additional 10 days. Cook Unit 2 has a generating capacity of 1,090 megawatts. After Unit 2 is returned to service, AEP will enter a planning period to establish the final restart schedule for Unit 1. The units have been idled since September 1997 because of questions raised about operability of safety systems. AEP, a global energy company, is one of the United States' largest investor-owned utilities, providing energy to 3 million customers in Indiana, Kentucky, Michigan, Ohio, Tennessee, Virginia and West Virginia. AEP has holdings in the United States, the United Kingdom, China and Australia. Wholly owned subsidiaries provide power engineering, energy consulting and energy management services around the world. The company is based in Columbus, Ohio. On Dec. 22, 1997, AEP announced a definitive merger agreement for a tax-free, stock-for-stock transaction with Central and South West Corp., a public utility holding company based in Dallas.