Nuclear Plant Journal, September-October 2015 NuclearPlantJournal.com
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Sherry Bernhoft
Sherry Bernhoft is the Program Manager
for Long Term Operations within
Electric Power Research Institute’s
(EPRI) Nuclear Sector. In this position
she is responsible for
strategic planning and
managing a portfolio of
research projects that
provide the technical
basis for safe, extended
operations of nuclear
power plants. These
R&D projects are
heavily leveraged with
the US Department
of Energy and EPRI’s
international partners.
Sherry holds a
Chemical Engineering degree from
Lafayette College, an MBA from Webster
University, a Senior Reactor Operator
Certification from Crystal River-3, and
a Shift Technical Advisor Certification
from the Kewaunee Nuclear Power
Plant.
management programs and in providing
robust safety reviews of license renewal
applications in a timely manner. A lot of
other countries that are going through
the license renewal process are using
some form of the US guidance (including
our standard review plan (SRP) and our
Generic Aging Lessons Learned (GALL)
document. We worked with IAEA to
help them develop what they now call
IGALL, or their International Generic
Aging Lessons Learned document that
they’re sharing with other countries. And
then they’re adding on to that applicable
guidance to cover other components and
other reactor designs such as the VVER,
the Russian reactors, and from the
Canadian CANDU design. We do a lot of
collaboration on the international side to
help ensure that safety reviews for license
renewal are at an appropriate level, and to
share lessons learned.
5.
Is digital upgrade going to be
mandated or voluntary?
Miller:
As part of our license renewal
regulations, which are in 10 CFR 54,
active electrical systems, such as digital
controls, are not in the scope. We don’t
review active components in our license
renewal program as those components
are covered by other regulations for
operating reactors in the US. The way
we deal with active components is the
maintenance rule, and an inspection
program that ensures that utilities are
maintaining their active components
effectively. If they have failure rates
that are unacceptable, then licensees are
required to take additional actions. We
have a category in the maintenance rule
requiring additional oversight for systems
that do not meet target requirements. We
do not specify a requirement for systems
to be digital.
6.
Has there been an effort that will
ensure that the plants meet the criteria
that the steam generators do not degrade
as they have been?
Bernhoft:
The NRC has set what
the requirements are to ensure that
steam generator tubing has an adequate
safety margin. EPRI was involved in
that research, and we continue to study
degradation rates on various materials and
components and the effects of corrosion
and other potential damage over time to
ensure that we provide guidance and the
technical bases for it to address repair
criteria and safety margin fully.
We’re doing a lot of research
to understand the management with
regard to reactor vessels. A lot has been
accomplished in this area of research. It’s
very important that we
continue to have some
type of surveillance or
monitoring program,
and we’re starting to
run into a shortage of
surveillance capsules.
So we’ve already done
the work under the
MRP with the PWRs to
defer harvesting some
of the capsules, so that
they’ll get a longer
fluence, out closer to 80
years and re-introduce
capsules into two host plants. Taken
together these two programs will greatly
increase the number of surveillance
capsules that have higher fluence levels
for testing.
Inside of the vessels in the United
States, there are small samples of the
actual vessel material. They’re located in
the core so that they get a higher fluence
level. They get what we call a lead factor.
So you can extrapolate, saying that if your
plant maybe only operated for 25 years,
your sample is really going to be more
resembling, say, 42 years of experience
when you harvest it and test it. So you
want to get a good lead factor on it. EPRI
keeps a common database so the rest of
the plants can see where they trend on that
database. They have to understand exactly
the amount of copper or phosphorus in
their vessel and how they compare to that
database, but we keep the database. And
we get everybody’s surveillance capsule
results. Knowing that some plants want to
consider a total life of 60 to 80 years, we
want to make sure that there are enough
results to fully inform their decisions,
and we’ve completed that work with the
PWRs.
Miller:
The NRC has robust
regulations and inspection guidelines to
ensure that adequate safety is maintained
for Steam Generators in plants operating
in their first 40 years, and those operating
in a renewed license period beyond 40
years. Besides those robust inspection
and design requirements for all operating
reactors, those plants that submit an
application for license renewal must
demonstrate adequate aging management
programs for steam generators and other
components within the scope of license
renewal, including reactor vessels and
reactor vessel internal components. Many
other condition monitoring requirements
also apply, including programs for
managing of water chemistry. Lessons
learned from previous Steam Generator
failures must be taken into account for
adequate aging management programs.
7.
Is the NRC and the industry ready
for the regulating guidelines to extend
the plant life to 80 years? Is there a pilot
project in place?
Miller:
The NRC will be ready
with its guidance when the first reactor
applications for license renewal to 80
years are expected. However the NRC
does not have a pilot project for the
subsequent license renewal application
reviews to 80 years. For the first couple of
applications that come in for subsequent
