BRATTLEBORO -- It's official.

On Monday, Sept. 23, Entergy Nuclear Operations informed the Nuclear Regulatory Commission that in the fourth quarter of 2014, it will permanently cease power operations of its Vermont Yankee nuclear power plant in Vernon.

"VY will continue to operate until the end of the current operating cycle," noted the letter to the NRC. "A more specific date cannot be provided at this time in order to allow for fuel coastdown variables."

Once the variables of the plant's fuel usage have been calculated, Entergy will submit a supplement certifying the exact date on which operations will cease.

Vermont Yankee operates on an 18-month fuel cycle. It most recently exited a refueling outage on April 5, 2013, meaning its final power-down could occur sometime in October 2014.

On Aug. 27, Entergy announced via Twitter its decision to close the plant.

Later that same day, during a press conference at Entergy headquarters on Old Ferry Road in Brattleboro, Bill Mohl, president of Entergy Wholesale Commodities said after several months of analysis and discussion, Entergy's board of directors had reached the conclusion that Yankee's continued operation was no longer financially viable.

The primary reason for its closure, said Mohl, was the reduced cost of natural gas due to innovations in hydraulic fracturing.

Even though the plant will cease operations sometime late next year, activity will continue to get it ready for what is called SAFSTOR, in which a plant is mothballed to allow its decommissioning fund to grow to a level necessary to fully complete remediation of the site. According to NRC regulations, Entergy has up to 60 years to commence cleanup of the site. The state would like cleanup to begin immediately, thereby allowing the site to be returned to some sort of use as quickly as possible.

Even if Entergy changes its mind and decides to start cleaning up immediately, a portion of the site will be off limits due to storage of nuclear waste that was produced since the plant began operating in 1972.

Bob Audette can be reached at raudette@reformer.com, or at 802-254-2311, ext. 160. Follow Bob on Twitter @audette.reformer.