Page 16 - Nuclear Plant Journal - March April 2013
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16
Nuclear Plant Journal, March-April 2013
Research &
Development
Inspection of Concrete
Structures
EPRI is pursuing thedevelopment and
demonstration of a robotic nondestructive
evaluation tool that would facilitate the
safe inspection of concrete structures at
nuclear power plants.
The energy industry contains a
number of large, curved vertical structures
where structural inspection is required,
including cooling towers, nuclear
containments and hydroelectric dams.
Inspecting these structures typically
requires several people and the use of
extensive scaffolding. Automating such
inspections would increase safety and
reduce inspection time and costs.
To identify candidate automated
robotic technologies, EPRI conducted
a wide-ranging review of available
technologies, their readiness levels, and
whether they could be adapted to the
electricity sector. Through this search,
EPRI came across a “concrete crawler”
device that can crawl up curved, vertical
concrete structures carrying a payload
of about 20 kilograms. This crawler also
can navigate gaps, seams and obstacles
that may be encountered on the concrete
surface, such as conduit.
EPRI evaluated various mapping and
positioning systems for this application
and selected the Simultaneous Mapping
and Location System code developed by
the Technical University of Darmstadt
in Germany, which could be configured
to the crawler. Likewise, an NDE device
capable of collecting information by
means of air coupling was identified and
mounted on the crawler.
Ademonstration during the Fall 2012
confirmed the individual capabilities of
the subsystems, and EPRI is now pursuing
integration of the crawler, positioning
system and NDE device. The first field
demonstration of the integrated device
will be at a hydroelectric dam in 2013.
The lessons learned from this application
are expected to be readily transferred
to nuclear containments and cooling
towers.
Contact:
Maria
Guimaraes,
telephone: (704) 595-2708, email:
Aging Management
Programs
To support decisions regarding long-
term operations, EPRI is reviewing the
technical basis underlying plant aging
management programs to determine if
changes are needed to address identified
technical gaps.
Assessing the viability of safe,
reliable plant operations over extended
time periods requires an understanding
of the technical basis supporting such
long-term operations (LTO). In the
United States, the Nuclear Regulatory
Commission has gradually formalized
the evaluation of aging management
programs as a key attribute of the license
renewal process; in other countries,
similar mechanisms are in place or
under development. Through its LTO
Program, EPRI is reviewing the technical
bases underlying aging management
programs for nuclear structures, systems
and components (SSCs) to confirm that
the bases support extended operations
or to identify R&D gaps. An ongoing
project aims to develop a technical basis
document that:
Identifies likely enhancements and
•
gaps in current aging management
programs and highlights gaps that
need to be filled to address technical
issues for safe long-term operations
Supports plans for incorporating
•
research results and operating
experience into aging management
programs.
Can be maintained as a tracking tool
•
to ensure all significant research gaps
are addressed in an adequate time
frame to support LTO.
To date, this project has completed
initial assessments of R&D needs for
aging management programs related
to operation beyond 60 years. These
assessments are now undergoing
peer review and refinement, and will
provide a critical link between the aging
degradation knowledge base and a plant’s
aging management actions, such as
periodic inspections, operating parameter
monitoring and control, and periodic
tests. For example, the EPRI Coordinated
SurveillanceCapsuleProgramwillprovide
reactor pressure vessel embrittlement
data at neutron fluence levels beyond
those expected at 60 years of operation.
This data will then serve as a basis
for inspection and monitoring actions
under a corresponding reactor pressure
vessel aging management program for
operation beyond 60 years. Similarly, an
EPRI project to develop a first-of-a-kind
containment assessment guideline (to be
published in 2013) will inform utility
decisions on aging management actions
for containment.
Contact: Rich Tilley, telephone: (704)
595-2597, email:
Non-Contacting Laser
Scanner
Development, demonstration and
deployment of this technology could
reduce or eliminate problems caused by
fuel distortion, such as the inability to
insert control blades.
The distortion of fuel assemblies
and channels due to in-reactor irradiation
can significantly impact both boiling and
pressurized water reactors. The distortion
can result in axial, lateral and torsional
displacements that affect the ability to
insert control rods or blades during plant
operations and that negatively impact
fuel handling during outage activities.
Accurate quantification of this distortion
is necessary so that mitigating strategies
can be implemented to limit or eliminate
these impacts.
EPRI is investigating the feasibility
of non-contacting technologies using
an array of lasers and optical cameras
to potentially improve distortion
measurements. The challenge is to make
these measurements such that outage
