Monday, December 2, 2013

SAFSTOR: On Decommissioning Vermont Yankee

Mark 1 Schematic

SAFSTOR is a method for delayed decommissioning of a nuclear plant. With SAFSTOR, fuel is taken out of the reactor and put in the fuel pool.  Then the plant remains basically intact for some years.  After some time (up to 60 years after fuel is removed from the core) the plant is fully decommissioned.

Vermont Yankee opponents are very determined that the plant should not be put in SAFSTOR. However, even the opponents are beginning to realize that Entergy's agreement about buying the plant (state agreement), and the Nuclear Regulatory Commission (federal oversight)  allow the use of SAFSTOR.  The opponents will not have much to say about what decommissioning methods (including SAFSTOR) Entergy chooses.

One advantage of SAFSTOR is that the workers who decommission the plant will be exposed to less radiation, because much of the radiation has decayed away.

The opponents are opposed to SAFSTOR, because they consider the "danger" of the plant (danger to them) while it is in SAFSTOR is a far more important problem than any extra radiation exposure to nuclear workers.  The opponents are personally very frightened (or they say they are).  Simultaneously, they are very willing for other people to face increased radiation.

In contrast, in an article at WCAX, Bill Irwin of the Vermont Department of Health says the plant will be generally safer after shutdown, even in SAFSTOR.

(Irwin) uses the analogy of a boiling pot: When the pot is hot and the water boiling, they're more concerned about spills. But a pot of cold water won't boil over -- though it could still leak, which is what they'll look for. But as the years go by, they will have to monitor a smaller and smaller area


In this case, opponents are  not going to get what they want.  According to the Memorandum of Understanding, the agreement by which Entergy bought the plant, SAFSTOR is an option for decommissioning.  It is also the option which Entergy has always said it would choose.

In an article by Susan Smallheer in the Rutland Herald, Mike Twomey of Entergy was quoted as follows:

Michael Twomey, vice president of external affairs for Entergy Nuclear, Yankee’s owner, told the panel Thursday that while the company was leaning toward a delayed decommissioning, it’s not a given that it will take all 60 years allowed by the Nuclear Regulatory Commission.

But Twomey said there would be little activity at the plant, except for handling spent fuel, in any event, for six to 10 years after it shuts down in late 2014. Twomey, who recently testified before two Vermont House committees on the plant’s pending shutdown, said the company had two years after the reactor actually stops generating power next year to study how much it would cost to decommission the plant, and choose a course for federal regulators.

Entergy has two years to file a decommissioning plan with the Nuclear Regulatory Commission. It plans to have little activity at the plant for six to ten years after the plant shuts down. For six to ten years (at least) the plant will be in SAFSTOR.

Architecture is Destiny

In terms of decommissioning, one of the things I have thought about is the position of the fuel pool at Vermont Yankee.

Once fuel is removed from the core, it must stay in the fuel pool for about five years before it can be put into dry cask storage. At Vermont Yankee,  the fuel pool is in the same building as the reactor. Therefore, it would be very hard to begin dis-assembling the reactor while maintaining the fuel pool.

The obvious schedule would be to wait about five years for the fuel to cool, and then transfer it to dry casks. After the transfer, when the fuel pool no longer needs to be maintained, the workers could begin   dis-assembling and decommissioning the reactor, the fuel pool and the reactor building.

I expect that this  is Entergy's plan. The protestors in Vermont cannot change the internal arrangement of the plant. Therefore, Entergy's plan will be the way the plant is decommissioned.

More on Decommissioning

This is one of a series of posts on issues on decommissioning Vermont Yankee.  The earlier posts:

Vermont Yankee Site Unlikely to be Used Again.  There are many vacant industrial sites in the Northeast: adding one more is unlikely to attract a new business.

Backwards reasoning about Greenfields.  Insisting on expensive "greenfield" work will not make the site more attractive to another business, and will slow down site availability.

The Formal Negotiations.  Shumlin's team and Entergy are sitting down together, in closed session.  They are discussing"issues" such as "how long fuel has to stay in a fuel pool."  (Issues? Facts, maybe..)


Howard Shaffer said...

Great post!
The meeting with the Governor today is all for show. He cannot negotiate physics! Five years are needed for Used Fuel to "cool" (this really means for the heat production rate to decrease) to the point where air cooling is sufficient.

jimwg said...

A SafStored Reactor is like global climate life insurance in the bank -- if only people had the sense and reason to regard it as such!

James Greenidge
Queens NY

Joffan said...

and What's The Damned Hurry anyway? The site is not urgently required for any other purpose and is unlikely to be used for another industrial or commercial business in the near future. There is plenty of greenspace in the area and the dam is close by, so it's not exactly a wilderness area.

The whole point appears to be trying to punish Entergy for running a nuclear power station, which has been an implicit theme in all the state's dealings with VY since I can remember.

Anonymous said...

All the meetings, "negotiations", legislation, pressure by Senators on the NRC, and protests will not change the Way-Wigner formulas. The laws of physics are not suggestions, nor are they open for "nuanced" interpretation. Nature is what it is. I think your Governor may have a hard time accepting that, but all of his soundbites and denigrating of "Entergy Louisiana" won't have any effect on radioactive half-life. They're going to have to maintain those systems for at least five more years, preferably longer, to get that fission product activity down.

Engineer-Poet said...

In the legal lexicon, there's the concept of the "vexatious litigant":  someone with no real legal complaint, but who uses lawsuits as a way to harass.

It would be very good if US nuclear policy recognized this concept and denied the likes of Schumlin, the Vermont PSC, Gunderson, and any government or organization of which they are a part any role in the evaluation or regulation of nuclear energy.

Anonymous said...

I have often thought that the existing system of essentially unlimited intervention is really an open invitation for abuse by intervenors. They know that the NRC is obliged by law to respond to petitions and other complaints. They know that the licensees are obliged by law to pay for almost the entire NRC budget through license fees. So the intervenors use the process as a back-door means of financially penalizing licensees. If they had to pay their own way for frivolous actions they bring then maybe they'd be less inclined to misuse the system.

John said...

Must admit I hadn't thought of jimwg's suggestion of SafStore as a means of simply putting the plant in mothballs, to be restarted if needed. It'd certainly be quicker and probably cheaper than building a new one. And a reliable source of energy where the price was not likely to vary markedly is obviously far more attractive to industry, and thus employment, than a 'greenfield' site. Still, I suppose the thing that most impresses me about the shutdown is the waste. To a penny pincher like me, shutting down a perfectly good plant that can go on generating power for years at a very low marginal cost is just foolish. Whether I was going to build more nukes or not, I'd certainly squeeze every last cent of value out of it if I was running things.

Engineer-Poet said...

"To a penny pincher like me, shutting down a perfectly good plant that can go on generating power for years at a very low marginal cost is just foolish."

It's beyond idiotic.  Vermont is losing a lot of tax revenue from the plant and its jobs, exporting money to out-of-state generators, and having to set aside tens of millions of dollars for fuel oil to guard against winter shortages of natural gas.  The "fuel diversity" payment of $78 million is over $120 per capita!

In a sane world, Shumlin would be regarded as criminal, not a leader.  His actions destroy Vermont's environment, economy and people.