AEP´s Cook Unit 1 sets unit generation record and begins refueling outage with $100 million in capital improvements projects

BRIDGMAN, Mich., Sept. 18, 2006 – American Electric Power’s [AEP:NYSE] Cook Nuclear Plant Unit 1 set a unit fuel cycle record for net generation as the reactor was safely shut down on Saturday to begin a refueling outage. In addition to refueling the reactor and regular outage maintenance and testing work, this outage includes replacing the reactor vessel head, the three low pressure turbine rotors and other major component and system improvements with total project costs of more than $100 million.

Projected totals show the unit operated at 98.2 percent capacity factor and generated 12,049 gigawatthours (GWH) of electricity during the 18 month fuel cycle. The previous record set during that last fuel cycle was 11,721 GWH. This is the 21st refueling outage since the plant went online in 1975.

“It is a tribute to our dedicated employees that both units have now completed the last two 18 month fuel cycles with record or near record generation,” said Mano K. Nazar, senior vice president and chief nuclear officer. “We have the right daily focus on safety and quality, and we’re doing the right work during outages to prepare our units to operate reliably.”

More than 1,800 contracted workers will supplement the regular 1,400-person plant staff. Approximately 14,000 maintenance, inspection and equipment modification job activities and 225,000 work-hours are scheduled.

The reactor vessel head replacement has been five years in planning and development. The replacement head incorporates corrosion resistant material that will improve safety and reduce expensive inspection requirements. The three low pressure turbine rotors will increase the output of the unit by up to 25 megawatts (MW) during summer operation and 40 (MW) during the winter.

Other major projects will improve turbine generator reliability and stability, significantly decrease worker radiation exposure in future outages and support the extended operation of the plant. Last year, the U.S. Nuclear Regulatory Commission approved a 20-year extension of the plant’s operating licenses to 2034 for Unit 1 and 2037 for Unit 2.

“This significant capital investment by AEP demonstrates our commitment to the surrounding communities and our customers, AEP shareholders, and our employees through the long-term operation of Cook Plant,” said Nazar.

The vessel head is approximately 17 feet in diameter and weighs 100 tons. It was forged in one piece in Japan and shipped to France for fabrication, which entailed complex welding operations and final machining to extremely precise tolerances. The 20-foot housings for the reactor control and shutdown equipment were also installed in France. Forging and fabrication of the new vessel head assembly took more than three years.

The container used to ship the head assembly from France was approximately 40 feet long, 17 feet in diameter and weighed 170 tons. It was transported by ocean vessel to Milwaukee and transferred to a barge that was towed to a temporary dock on the St. Joseph River. Since the container was too large for rail shipment, it was transferred to a heavy haul vehicle and traveled public roads at walking speed for the remaining eight miles to the plant.

Installation of the vessel head will be incorporated into the refueling process. The old head will be temporarily housed at the site before being shipped later this year for burial at a low-level radioactive waste disposal facility in Utah.

The three low pressure turbine rotors and inner casings were fabricated in Germany over the past two years. Each rotor is approximately 17 feet in diameter, 38 feet long and weighs more than 190 tons. Each rotor has two sets of 11 rows of blades that increase in size from two inches to five feet long. The project includes replacement of all the inner casings that house the rotors and most of the support equipment.

The material was transported by ocean vessel to Burns Harbor, Ind. The rotors were towed on a lake barge to the St. Joseph River and transferred to heavy haul vehicles. The rotors were moved one mile through Benton Harbor to a rail siding and completed the journey to the plant by rail. The old rotors and casings will be shipped off-site for disposal.

The design of the new rotors improves the efficiency of steam transfer that will increase the output of the turbine generator between 25 and 40 megawatts, or enough to power a city of approximately 40,000 people. The higher end of the range can be realized during winter months when the lower cooling water temperature also increases efficiency.

Two other outage projects, replacement of the main generator voltage regulator and upgrade to a digital turbine control system, will also improve the reliability and ease of operation of Unit 1 turbine generator.

Another major project is the removal of more than 500 feet of piping and 40 valves that were used to monitor reactor coolant temperature. New in-line temperature detection equipment will be installed and removal of the piping will significantly reduce future occupational radiation exposure at the plant.

Other major projects include: replacement of 60 4,000 volt circuit breakers; modifications to the containment building sump, modifications designed to eliminate vulnerability of safe operations to single points of equipment failure; preventive overlay welding on the reactor coolant system pressurizer; replacement of a reactor coolant pump and motor; and required inspections on the unit’s steam generators and integrity of the containment building.

“The number of major modifications makes this the most comprehensive outage ever at Cook and maybe in the industry,” said Nazar. “But we are well prepared to have an efficient and effective outage and the work being performed will position us to perform at industry best standards for decades to come.”

The refueling outage for Cook Unit 2 in the fall of 2007 will also include reactor vessel head replacement and several of the other major system and component improvements being done on Unit 1 in this refueling.

The 1,036 net megawatt (MW) Unit 1 and 1,107 net MW Unit 2 combined produce enough electricity for more than one and one half million average homes.

American Electric Power is one of the largest electric utilities in the United States, delivering electricity to more than 5 million customers in 11 states. AEP is the nation’s largest generator of electricity, owning more than 36,000 megawatts of generating capacity in the U.S. AEP also owns the nation’s largest electricity transmission system, a nearly 39,000-mile network that includes more 765-kilovolt extra-high-voltage transmission lines than all other U.S. transmission systems combined. AEP’s utility units operate as AEP Ohio, AEP Texas, Appalachian Power (in Virginia, West Virginia and Tennessee), Indiana Michigan Power, Kentucky Power, Public Service Company of Oklahoma, and Southwestern Electric Power Company (in Arkansas, Louisiana and east Texas). American Electric Power, based in Columbus, Ohio, is celebrating its 100th anniversary in 2006.

Bill Schalk
Communications Manager

More From AEP Ohio

Sign Up Now Pay Online for Free with Paperless Billing

Pay Online for Free with Paperless Billing

Learn More

You wanted a bill that is simple, clear and colorful

How We Restore Power Learn more

How We Restore Power

Find Out How Save Energy. Save Money

Save Energy. Save Money

Visit AEP.com
Use of this site constitutes acceptance of the AEP Terms and Conditions. View our Privacy Policy. © 1996-2019 American Electric Power. All Rights Reserved.

Privacy Policy

Privacy Policy for AEP Ohio, a unit of American Electric Power (AEP)


This Privacy Policy applies only to AEPOhio.com and the AEP Ohio customer mobile app (com.aep.customerapp.aepohio). Other AEP websites and apps may be governed by their own privacy policies, appropriate to the uses and needs of each. Throughout the site or app, we may provide links to resources and sites that are not part of AEPOhio.com or the AEP Ohio customer mobile app. This Privacy Policy does not apply to those resources and sites.


By using this site or app, you consent to the terms of this Privacy Policy. Whenever you submit information via this site or app, you agree to the collection, use, and disclosure of that information in accordance with this Privacy Policy.

Information Collected

  1. Passively collected information

    During your use of this site or app, we may collect anonymous information about your visit here through the use of server logs, cookies, scripts, tracking pixels and other Web traffic tracking systems. This information is aggregated and used to improve user experience through analysis of user activities. This information is never combined with any of the personally identifiable information you may provide in your use of the features of this site or app.
  2. Personally identifiable information

    On certain forms of this site or app, you may be asked to provide information about yourself or your account with us, either to identify yourself to us or to request a service from us. In each case, we will inform you what information is provided at your option and what information is required to complete the transaction or activity you are engaged in. If you are unwilling to provide this required information, you will be unable to complete the requested transaction.

Use and disclosure of information

The information you provide to us will be used to respond to requests you may make for services. Some or all of this information may be added to your permanent account record and may be used for research purposes.

In addition, we may use elements of this information in the following situations:

  1. We may transfer the information to AEP Ohio’s affiliates and subsidiaries, unless such transfer is prohibited by law;
  2. We may transfer the information as part of a merger, consolidation, acquisition, divestiture or other corporate restructuring (including bankruptcy);
  3. We may make the information available to third parties who are providing the product, service or information that you have requested (but not your password);
  4. We may make such information available to third parties who are providing services to AEP Ohio (for example, providing the information to third parties performing computer-related services for AEP Ohio);
  5. We may use the information to communicate with you about products and services that may be of interest to you.
  6. We may disclose the information if we form a good-faith belief that disclosure of such information is necessary to investigate, prevent, or take action regarding any illegal activities or regarding interference with the operation of our site or violation of its terms of use; or
  7. We may disclose the information if we believe that disclosure is required by law or regulation or in response to a subpoena or other order of a court or other governmental agency.

AEP Ohio uses Flurry Analytics Service (provided by Yahoo) in order to improve its mobile apps. Flurry’s privacy policy governs the use of this information.

Also, AEP Ohio reserves the right to share any aggregated information (i.e., non-personally identifiable information) with any third parties for any reason, unless prohibited by law.

We will not sell, rent or otherwise disclose the information we gather about you or your account to any third party, except as outlined in this Privacy Policy.


AEP Ohio takes reasonable steps to protect your personally identifiable information as it is transferred to us, through the use of Web technologies such as the Secure Sockets Layer and others. However, no Internet transmission of information is ever completely secure or error-free. In particular, e-mail sent to or from AEP Ohio may not be secure.

How to Reach Us

If you would like to update your personally identifiable information or if you have questions about this privacy policy, please contact us.

Changes to This Policy

AEP Ohio reserves the right to change this Privacy Policy at any time. If this Privacy Policy changes, the revised policy will be posted to this site. Please review this Privacy Policy before you provide any personally identifiable information through this site. Use of our web site after the posting of a revised privacy policy constitutes your consent to the revised policy.

This policy was last revised on December 13, 2017.

Close ×

Sign Up For Alerts

Subscribing to AEP Ohio alerts gives you instant notification for:

  • Billing & Payments - avoid late payments and disconnection
  • Outage Updates - find out if there's an outage at your address and when power will be back on

Win an Xbox One with Alerts!

Enroll in alerts to be eligible to win. Subscribing to I&M alerts gives you instant notification for:

  • Billing & Payments - avoid late payments and disconnection
  • Outage Updates - find out if there's an outage at your address and when power will be back on

Loading video...