A Beyond Nuclear Briefing Paper
Beyond Nuclear6930 Carroll Avenue Suite 400
Takoma Park, MD 20912
Tel. 301-270-2209
A
Beyond Nuclear Briefing Paper:
The
Subsequent License Renewal of Peach Bottom Atomic Power Station needs to be
scientifically informed by an “autopsy” performed on decommissioning nuclear
power stations of similar design to “reasonably assurance” material safety
margins projected for the second license extension
The
Issue
The Nuclear Energy Institute (NEI), the lead
organization for the U.S. commercial nuclear power industry, envisions the
industry’s “Bridge to the Future” through a series of reactor license renewals
from the original 40-year operating license; first by a 40 to 60-year extension
and then a subsequent 60 to 80-year extension.
Most U.S. reactors are already operating in their first 20-year license extension
and the first application for the second 20-year extension (known as the
“Subsequent License Renewal”) is before the U.S. Nuclear Regulatory Commission
(NRC) for review and approval. NEI claims that there are no technical “show
stoppers” to these second license renewals. However, as aging nuclear power
stations seek to extend their operations longer and longer, there are still many
identified knowledge gaps for at least sixteen (16) known age-related material
degradation mechanisms (embrittlement, cracking, corrosion, fatigue, etc.) that
are attacking irreplaceable safety-related systems including miles of electrical
cable, structures such as the concrete containment and components like the large
reactor pressure vessel. For example, the national labs have identified that it
is not known how radiation damage will interact with thermal aging. Material deterioration
has already been responsible for near miss nuclear accidents. As such, permanently closed and decommissioning nuclear power
stations have a unique and increasingly vital role to play in providing the still
missing data on the impacts and potential hazards of aging for the future
safety of dramatic operating license extensions.
The NRC and national laboratories document that a post-shutdown autopsy
of sorts to harvest, archive and test actual aged material samples (metal, concrete,
electrical insulation and jacketing, etc.) during decommissioning provides unique
and critical access to obtain the scientific data for safety reviews of the requested
license extensions. A Pacific Northwest
National Laboratory (PNNL) 2017 report concludes, post-shutdown autopsies are
necessary for “reasonable assurance that systems, structures, and components
(SSCs) are able to meet their safety functions. Many of the remaining questions
regarding degradation of materials will likely require [emphasis
added] a combination of laboratory studies as well as other research
conducted on materials sampled from plants (decommissioned or operating).”
PNNL reiterates, “Where available, benchmarking can be performed using surveillance
specimens. In most cases, however, benchmarking of laboratory tests will require (emphasis added)
harvesting materials from reactors.” In the absence of “reasonable assurance,” it is
premature for licensees to complete applications without adequate verification
and validation of projected safety margins for the 60 to 80-year extension
period.
Decommissioning is not just the process for dismantling nuclear
reactors and remediating radioactive contamination for site restoration.
Decommissioning has an increasingly important role at the
end-of-reactor-life-cycle for the scientific scrutiny of projected safety
margins and potential hazards at operating reactors seeking longer and longer
license extensions.
The
Problem
After decades of commercial power operation, the nuclear industry and the NRC have done surprisingly
little to strategically harvest, archive and scientifically analyze actual aged
materials. Relatively few samples of real time aged materials have been shared
with the NRC. The NRC attributes the present
dearth of real time aged samples to “harvesting opportunities have been
limited due to few decommissioning plants.” However, ten U.S. reactors have
completed decommissioning operations to date and 20 units are in the decommissioning
process. More closures are scheduled to begin in Fall 2018. A closer look raises significant concern that
the nuclear industry is reluctant to provide access to decommissioning units
for sampling or collectively share this cost of doing business to extend their operating
licenses. Key components including severely embrittled reactor pressure vessels
were promptly dismantled by utilities and buried whole without autopsy. Many permanently
closed reactors have been placed in “SAFSTOR,” defueled and mothballed “cold
and dark” for up to 50 years without the material sampling to determine their
extent of condition and the impacts of aging. Moreover, the NRC is shying away
from taking reasonable regulatory and enforcement action to acquire the
requested samples for laboratory analysis after prioritizing the need for a
viable license extension safety review prior to approval. Meanwhile, the
nuclear industry license extension process is pressing forward.
David Lochbaum, a recognized
nuclear safety engineer in the public interest with the Union of Concerned
Scientists, identifies that nuclear research on the impacts and hazards of age degradation in nuclear
power stations presently relies heavily on laboratory accelerated aging---often
of fresh materials---and computer simulation to predict future aging
performance and potential consequences during license extension. Lochbaum explains that “Nuclear autopsies
yield insights that cannot be obtained by other means.” Researchers need to
compare the results from their time-compression studies with results from tests
on materials actually aged for various time periods to calibrate their
analytical models. According to
Lochbaum, “Predicting aging effects is like a connect-the-dots
drawing. Insights from materials harvested during reactor decommissioning
provide many additional dots to the dots provided from accelerated aging
studies. As the number of dots increases, the clearer the true picture can be
seen. The fewer the dots, the harder it is to see the true picture.”
The
Path Forward
1) Congress, the Department
of Energy (DOE) and the NRC need to determine the nuclear industry’s fair share
of autopsy costs levied through collective licensing fees for strategic harvesting
during decommissioning and laboratory analysis of real time aged material
samples as intended to benefit the material performance and safety margins of
operating reactors seeking license extensions, and;
2) As NRC and the national laboratories define the
autopsy’s stated goal as providing “reasonable assurance that systems,
structures, and components (SSCs) are able to meet their safety
functions” for the relicensing of other reactors, the NRC approval
process for Subsequent License Renewal extensions should be held in abeyance
pending completion of comprehensive strategic harvesting and conclusive
analysis as requested by the agency and national laboratories, and;
3) Civil society can play a more active role in the
independent oversight and public transparency of autopsies at decommissioning
reactor sites such as through state legislated and authorized nuclear
decommissioning citizen advisory panels.
Link to the Beyond Nuclear Decommissioning Autopsy Whitepaper and
documentation
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