Entergy’s Arkansas Nuclear One Unit 1 returns to service after reactor vessel head repairs

Nov. 13, 2002 — Unit 1 at Entergy’s Arkansas Nuclear One is back on line, generating electricity after shutting down Oct. 4 for refueling and maintenance. Unit 1’s 17th refueling outage ended Tuesday after 39 days. Unit 1 set an ANO record with 435 days of continuous operation leading up to the Oct. 4 shutdown.

In addition to replacing about a third of 177 fuel assemblies in the Unit 1 reactor, major outage work included inspections of the reactor vessel head and tubing in both steam generators.

All 69 reactor vessel head nozzle penetrations were thoroughly inspected. A small leak associated with one nozzle was identified and indications of flaws were discovered in seven other nozzles that were not leaking. All eight nozzles were repaired prior to restart of the unit.

Inspections of reactor vessel heads for pressurized water reactors have taken on a new significance since February when severe reactor vessel head corrosion was discovered at the Davis Besse nuclear plant in Ohio. Corrosion there resulted from leakage of reactor coolant containing boric acid, an additive that regulates reactor power by absorbing neutrons. This condition is unique to pressurized water reactors. The ANO Unit 1 reactor vessel head material had no such corrosion.

Fabrication of a new Unit 1 reactor vessel head and two replacement steam generators for the two currently in service for the unit is in progress. Company officials plan to install the replacement components in 2005 during the unit’s 19th refueling shutdown.

2001 was ANO’s best year yet for production. The two units combined to generate 14.7 million megawatt-hours of electricity, the most ever for the site. This equates to about a third of the overall electricity consumption in Arkansas.

Unit 2 also set a unit-best record generating 7.9 million megawatt- hours of electricity. ANO’s performance was cited as a major factor in electricity prices to Entergy Arkansas customers being nearly 10 percent lower in spring 2002 than a year earlier.

Entergy (NYSE: ETR – News) is a major global energy company with power production, distribution operations and related diversified services. The nuclear businesses of Entergy Corporation are headquartered in Jackson, Miss. Entergy Nuclear is the second largest and fastest growing operator of nuclear power plants in the nation.

It operates five reactors at four locations in Arkansas, Mississippi and Louisiana under regulatory jurisdictions and an additional five reactors at four merchant sites in Massachusetts, New York and Vermont. Entergy Nuclear also is the nation’s largest provider of license renewal and decommissioning services to the nuclear power industry.

Entergy Nuclear’s online address is www.entergy-nuclear.com .

Source: Entergy Corporation

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