Showing posts with label Bill Irwin. Show all posts
Showing posts with label Bill Irwin. Show all posts

Monday, December 2, 2013

SAFSTOR: On Decommissioning Vermont Yankee

Mark 1 Schematic
SAFSTOR  Safety

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

SAFSTOR Facts

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..)



Friday, March 19, 2010

Vermont Health Department on Tritium


WCAX interviewed Bill Irwin, head of the Radiological Health area of the Vermont Department of Health. The heading for this interview was: Expert: Vermont Yankee May Have Other Vulnerable Areas.
The content was:
  • We found the source of the leak
  • It has stopped leaking.
But the tone was quite negative. More could go wrong! Yes. More could always go wrong.

It reminds me of getting a test result from a yearly mammo. I get a letter that says something like: your mammogram is clear. However, there could be cancer somewhere else in your body, and some cancers are not detected by mammos, etc etc etc. In other words, a long warning that translates:

Your test is okay. But something else could go wrong. We're not making any promises.

Life is always uncertain. Still, these warnings generally mean: We are doing some serious CYA here. (CYA is shorthand for "Cover Your Donkey")

Let's take the main result instead, okay guys?

VY found this tritium leak. They fixed it. Cause for celebration!

Also, Rod Adams has an excellent post on the total amount of tritium that leaked, top to bottom, all the tritium in the famous plume of tritiated water under the plant. Spoiling the suspense of reading his post: less than half a curie of tritium leaked, total, at Vermont Yankee. In contrast, a well-operated CanDu reactor in Ontario releases 5,000 curies of tritium a year into the environment, or 14 curies per day. These releases are well within the legal limits in Canada, limits designed to expose the public to far less radiation from tritium than they receive from background.