The Ft. Calhoun, Nebraska nuclear power plant must close by the end of the year, says Omaha Public Power District’s chief executive, Tim Burke, who says the plant is just too expensive to run.  Ft. Calhoun has been plagued with problems including a fire, and in 2011 was famously surrounded by flood waters from the Missouri River.  Earlier this month, Exelon announced it would close two Illinois nuclear plants -- Quad Cities and Clinton -- if the state failed to prop them up.  The Oyster Creek reactor in New Jersey and the Pilgrim reactor in Massachusetts are both scheduled to close in 2019. Meanwhile the Tennessee Valley Authority has given up on its two planned Bellefonte reactors and is instead putting the incomplete plant up for sale.  TVA spent a reported $5 billion plus on the project but the sale price -- if indeed there are any buyers -- is estimated at $36.4 million. More on Ft. Calhoun. More on Bellefonte.