Don’t expect a giant mushroom cloud to appear over the golden dome in Montpelier tomorrow when the state senate debates a measure allowing for the relicensure of Vermont Yankee beyond its scheduled closing date of 2012.

Check out Seven Days' recent news package examining the Vermont Yankee debate.

It's likely that the senate will vote down the measure, but not before taking up a motion to send the bill back to committees for further review of the economic impact of shutting down the plant in 2012.

In short, though the senate will probably vote against relicensure, I don't suspect this issue will go away anytime soon.

Besides, it's not as if the plant has to shut down tomorrow. In fact, its operators plan to replace roughly 120 fuel assemblies in April. Each assembly lasts as long as four-and-a-half years. Despite the senate vote, which could call into question VY's future, the refueling will go ahead as scheduled.

"The refueling outage will not be affected by the legislative vote," said VY spokesman Larry Smith. "Refuel outage will not be affected by the tritium leak if we do not find it and stop it before that. The plan is to find it and fix it before the outage."

By its own admission, Entergy's drop-dead date for a decision on relicensure isn’t until April 2011. That’s an eternity in politics, and Entergy knows this is not a short-term fight. Vermonters' trust will take months to regain.

It's also a possibility that a negative decision could end up in court.

A WCAX poll last week proves how far Entergy has to go: Nearly half of 400 Vermonters polled say VY should be closed in 2010, with another quarter not sure and only a quarter in favor of giving it another 20 years to operate.

Even if no other measure is taken up in this legislature, another vote could occur in 2011. That’s when a new legislature will be seated, along with a new governor and lieutenant governor.

Hmm ... think this will be a campaign issue?

Backers of both sides of the issue have been stepping up public and media pressure in recent days, as a recent story on Vermont Public Radio noted.

But, right on schedule, VY and its owner, Entergy, proved to be their own worst enemies in the days leading up to the vote.

Yesterday, the U.S. Nuclear Regulatory Commission revealed that, in fact, a whistleblower's claim last week about a previous tritium leak was accurate. It's investigating further, as is the state Public Service Department, to determine what other documents on file say about the leak and its repair.

Not only did the leak occur, but it happened in the very spot thought to be the source of the current tritium discharge — pipes in a 3-by-4-foot concrete trench known as the advance off-gas system.

The previous leak occurred in 2005, four years before Entergy officials told the state they had no knowledge of underground pipes.

The report of the leak was contained in a “plant condition report,” said Neil Sheehan, an NRC spokesman.

The whistleblower claimed the leak was temporarily fixed with a sealant until the plant was shut down during a refueling to allow a more permanent fix.

In an effort to stave off the bad press, Entergy released a new energy offer in a last-ditch attempt to sweeten the deal for some of Vermont's utilities. Entergy agreed to provide 2 percent of the state's power needs, or 25 megawatts of power, at the current rate of 4 cents per kilowatt hour for the first three years of its new license. It would provide the remaining power — up to 15 percent of the state's needs — through Green Mountain Power and Central Vermont Public Service at 6 cents per kilowatt hour.

Senate leaders said the offer does not answer other concerns about the health of the decommissioning fund or the plan to spin off ownership to a new company.

Among pols, the move to go ahead with the vote is largely backed by Democrats, with one notable exception.

Sen. Susan Bartlett (D-Lamoille) is the only one of the five Democratic candidates for governor who said the legislature should take more time before voting. That said, she still thinks the plant should be closed in 2012 — it's just too soon to vote.

Her four counterparts — led by Senate President Pro Tem Peter Shumlin — disagree. Both Secretary of State Deb Markowitz and former State Senator Matt Dunne have been arguing for weeks that the legislature should vote sooner rather than later — and vote to shut VY down. State Senator Doug Racine, too, said the state needs to take action and help VY workers plan for the future, as well as some of Vermont's utilities.

Meanwhile, two Republicans running for lieutenant governor, Sen. Phil Scott (R-Washington) and Mark Snelling, are both urging the legislature to take more time to review the decision. That's the same tack taken by Gov. Jim Douglas and Lt. Gov. Brian Dubie.

The Vermont Senate vote tomorrow on whether to relicense VY for another 20 years is making international headlines.

The UK Guardian has a story on its website today titled "Obama's nuclear vision suffers setback as Vermont plant faces shutdown."

President Barack Obama recently announced billions of dollars in loan guarantees to build new nuclear plants in the United States. The first two are likely to be built in Georgia.

Late today, Republican U.S. Senate candidate Len Britton said he agreed with Rep. Patricia O'Donnell (R-Vernon) that the state should seek federal funding to build a state-of-the-art reactor to replace the aging reactor.

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I'll be doing my best to provide live coverage of the Senate debate via Twitter. You can follow me, or follow the hashtag #vty for all things VT Yankee-related.

To listen to the Senate debate, tune into Vermont Public Radio's live legislative stream.

To watch the Senate debate, tune into Vermont Public Television's website.

The debate is scheduled to begin around 10:30 a.m.