Tritium could affect VY cleanup costs
Mar 15 - McClatchy-Tribune Regional News - Bob Audette Brattleboro
Reformer, Vt.
The possible remediation costs of contaminated groundwater at Vermont
Yankee nuclear power plant in Vernon due to a leak of tritiated water is
dependent on a number of conditions, said a spokesman for the Nuclear
Regulatory Commission.
The tritium decay rate is just one of those factors, said Neil Sheehan.
Tritium has a half-life of 12.3 years, which means it will have lost
half of its radioactivity during that period of time.
Other factors include groundwater flows, whether pumping contaminated
water out of the ground could actually spread the plume and calculations
used to determine the maximum amount of radioactive exposure that
members of the public could experience as a result of the contamination.
"Entergy is still developing that information," said Sheehan, adding the
NRC will review any and all remediation plans once they are completed.
Entergy, which owns and operates the power plant, has indicated
it plans to place Yankee into SAFSTOR for several decades following
shutdown, whenever that occurs, he said.
SAFSTOR is an NRC-approved method of mothballing a plant until much of
the radioactive contamination at a plant has decayed and to allow a
decommissioning fund to grow to the level sufficient to pay for cleanup.
Entergy has applied to the Nuclear Regulatory Commission to extend the
operating license of Yankee for another 20 years, from 2012 to 2032.
In 2008, Entergy told the NRC
that it has estimated there is 135,000 cubic feet of contaminated soil
that would have to be removed at Vermont Yankee during decommissioning,
with an estimated cost of $76 per cubic foot.
The total cost for that remediation would be $10,260,000, in 2008
dollars.
The 2008 report did not specify where the contamination came from, said
Sheehan.
"The cost reported for soil remediation is based upon a preliminary
assessment of the potential for contamination in the soil around the
plant, based upon historical evidence," stated the report. "A detailed
site characterization was not performed. This allowance will be
confirmed and/or modified based upon more detailed analyses to be
performed in conjunction with the formulation of a license termination
plan."
How the tritium leak might affect cleanup costs is not known at this
point, said Sheehan.
"Because Entergy has not yet finished characterizing the extent of the
contamination from the tritium leakage, it would be speculation at this
point as to how much additional soil might have to be removed or what
the price tag for that work might be," he said.
Under its regulations, the NRC requires remediation of residual
radioactivity to a level that permits, in most cases, unrestricted
release of the site, said Sheehan.
"Once contaminated plant systems and structures are removed, any
residual radioactivity would have to be reduced to a level at which a
member of the public living on the site 24 hours a day, 365 days a year,
would receive a maximum of 25 millirems of radiation exposure," he said.
The average American is exposed to roughly 360 millirems of radiation
from natural and manmade sources on an annual basis.
"Our decommissioning cost estimates are based on meeting these
requirements."
Sheehan said the principle of ALARA -- As Low As Reasonably Achievable
-- would also be taken into account.
"That means an effort would be made to drive those levels even lower,"
he said.
In addition, states can set a cleanup standard more restrictive than the
NRC's, said Sheehan. In Vermont's case, that level is 20 millirems.
"State projections of decommissioning costs can also cover the price of
returning the site to 'greenfield' condition,' he said.
An example of greenfielding would be the removal of an administrative
building or another structure that had nothing to do with the nuclear
power production process, he said.
"That is why state decommissioning cost estimates are typically higher
than those reviewed by the NRC," he said.
James Matteau, the executive director of the Windham Regional Council,
cautioned that even though the half life of tritium is relatively short,
it could take 50 to 100 years for it to totally dissipate from the site.
Of course, he said, that's also dependent on how much of the
contaminated water makes it to the Connecticut River and is washed
downstream.
Matteau also said it's the regional commission's position that SAFSTOR
is unacceptable. Instead, the WRC is calling for a "prompt" cleanup of
the site, which would commence about five years after shutdown, which is
enough time for the last of the spent fuel to cool off in the plant's
spent fuel pool.
WRC is also concerned about what effect SAFSTOR would have on employment
in the region.
"In SAFSTOR, the place gets mothballed, locked up and guarded for as
much as 60 years," said Matteau. "That means the jobs in the region will
go down to the absolute minimum for as long as 60 years."
In three generations, a whole new group of people will arrive to begin
the decommissioning, he said, and that means institutional memory would
be lost.
Prompt cleanup could also mean Entergy would have to include the costs
of tritium remediation in its decommissioning cost estimates, said
Matteau.
Bob Audette can be reached at raudette@reformer.com, or at 802-254-2311,
ext. 273.
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