Entergy Mississippi Inc. President and CEO Carolyn Shanks has accepted a top job with the power company’s developing nuclear entity, and the 25-year Entergy employee and nine-year state leader will be succeeded by Haley Fisackerly, vice president of governmental affairs for Entergy Nuclear.

Each will take the new positions over a period of several weeks, a company release said this morning.

Shanks, 46, and one of few women CEOs of major Mississippi companies, will serve in her new role as senior vice president of administration and corporate support, with oversight of communications, human resources, information technology and corporate services.

“Without question, these have been some of my most rewarding years with Entergy,” Shanks said in a statement. “From the start, it was vital to win back the trust of customers while truly making a difference in the communities we serve.”

A Senatobia native, Shanks started as an accountant for Mississippi Power & Light in 1983 and later joined System Entergy Resources Inc., the subsidiary operating Grand Gulf Nuclear Station. She became president and CEO in 1999 and is credited with launching initiatives geared toward customer satisfaction.

Fisackerly, 43, will assume responsibility of Entergy Mississippi’s electric distribution system, customer service, economic development, regulatory affairs and governmental affairs.

“I look forward to working with employees as we find even more ways to improve our performance,” Fisackerly said. “It’s an exciting time to be part of the Entergy Mississippi team, and I think this will be a transformational era as we prepare for the challenges of the future.”

A Columbus native, Fisackerly received a business degree from Mississippi State University and an MBA from George Washington University. He joined Entergy in 1995 in federal government affairs. Following a stay in Little Rock, Ark., he returned to Mississippi in 2002 as vice president of customer operations. He has served in his current position since June 2007.

Both Shanks and Fisackerly will have offices in Jackson.

The changes do not figure to alter its focus on nuclear energy in the state.

“Haley is experienced and is very aware of the needs in that area,” Entergy spokesman Checky Herrington said.

Entergy Mississippi provides electricity to more than 433,000 customers in 45 counties. It is a subsidiary of Entergy Corporation, based in New Orleans, which owns and operates power plants with about 30,000 megawatts of electric generating capacity, and it is the second-largest nuclear generator in the United States. Entergy delivers electricity to 2.6 million utility customers in Arkansas, Louisiana, Mississippi and Texas.

Entergy Nuclear is in the seventh year of a 15-year process to add a second reactor at the Grand Gulf site in Claiborne County. It would be the nation’s first licensed reactor since 1996. As part of a consortium, the company has received early site approval and the project is now in the license application phase.