Since October 2012, electric power companies have announced the retirement of four nuclear reactors at three power plants. The four reactors have a combined capacity of nearly 3,600 megawatts (MW). The recent retirements are the first since 1998. Decisions to retire the units involved concerns over maintenance and repair costs and declining profitability.

via Today in Energy http://www.eia.gov/todayinenergy/detail.cfm?id=11931