Entergy's Vermont Yankee plant had been under siege by a nuclear-hostile governor (Pete Shumlin) and in particular targeted by anti-nuclear groups hoping to seize upon a legislative window to shut down the plant for good. To give some background: when the plant changed ownership to Entergy in 2002, a condition of the deal (signed in a memorandum of understanding with the legislature) was that Entergy agreed to submit an application with the Vermont Public Service Board (VPSB) for a "Certificate of Public Good" - in essence, a license required of all power operators. Vermont Yankee's current CPG expires on March 12, 2012.
Pray that Vermont does not alter
the deal any further.
Fast foward to the present. Entergy recently received an approval with its application to the NRC to re-license Vermont Yankee for another 20 years of operation (ending in 2032). (Side note: It cannot be over-emphasized that the original licensing period for reactors - 40 years - is one governed historically by anti-trust and economic considerations, rather than any scientific basis. Relicensing appliations are handled by the NRC on a case-by-case basis, wherein operators must prove the plant is physically capable of safely operating to NRC specifications over the extended time period.)
Then, in perfect keeping with Darth Vader's preferred negotiating style, the Vermont Senate passed a law blocking the VPSB from issuing such a certificate, thus attempting to circumvent the NRC and block the plant from operating. Again, this all is in spite of the fact that the NRC (staffed by trained engineering professionals) evaluated Vermont Yankee and determined it safe to operate; instead, this judgement was over-ruled by the governor and legislature of Vermont, distinctly lacking in such engineering credentials.
The full ruling turned essentially on how binding the MOU Entergy signed with the Vermont legislature was; in essence, the court's ruling was that this agreement bound Entergy to the jurisdiction and decision of the VPSB (i.e., obligating them to seek a certificate of public good), however such an agreement did not grant the legislature the right to pre-empt the decision process from the board. Thus, the legislature's move to circumvent the VPSB's process amounted to a change in the implicit contract with Entergy after the fact. (Such shenanigans were not limited to altering the deal after the fact - as has been covered in depth by Angwin, the legislature attempted in mafioso style to impose other conditions for receiving the certificate, such as requiring Entergy to sell electricity to the state at below-market rates.)
So what does this mean in the end for Vermont Yankee? Ultimately, the fate of the plant still rests in the hands of the VPSB, where Entergy must make the case to the board that Vermont Yankee provides an adequate balance of safety, environmental, and economic concerns relative to other sources in its continued operation. However, today's ruling now grants Entergy that opportunity, the same one afforded to all other energy producers in the state. Finally, unlike the Legislature, such a case in one judged by findings of fact rather than political arm-twisting.