Nuclear Plant Journal, March-April 2015 NuclearPlantJournal.com
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Tom Kline
Tom Kline is the Director of Concrete
Repair Solutions at STRUCTURAL
TECHNOLOGIES.
Tom is an expert in
concrete evaluation
and restoration
and focuses on
the evaluation,
assessment, and
repair/strengthening
of reinforced
concrete structures.
He manages
and directs a
diverse group of
technical experts in
providing design-
build capabilities,
developing turnkey repair strategies,
and implementing sophisticated and
verifiable repair programs for a
wide range of energy and industrial
customers.
rehabilitation of the deteriorated
reinforced concrete was required for
the walls, floor slabs, circulation water
bowls, and salt water pits.
After rehabilitation was completed
an Impressed Current Cathodic Protection
(ICCP) system was installed as part of a
preventative maintenance and monitoring
program to prevent future corrosion.
Rather than entering in the reactive
maintenance cycle of repairing as needed
and risking another incident, this long-
term protection solution was developed
to extend the life of these structures.
Underground Piping
Underground piping is exposed
to degradation from various types
of corrosion. As piping systems age,
corrosion, deterioration, and failures,
including leaks and ruptures, can occur.
Developing a predictive maintenance
program for piping should consider in-
corporation of a variety of condition as-
sessment techniques
including
visual
inspections,
wall
thickness measure-
ments, pressure test-
ing, leak detection
and an assessment
of coatings and ca-
thodic
protection
systems.
A
Northeast
nuclear facility has
been proactively ad-
dressing their bur-
ied piping through
inspection
and
targeted repairs for decades. This risk-
ranking process identifies repairs needed
in the Circulation Water system piping.
Recently, seven segments of 144 inch-
diameter pre-stressed concrete cylinder
pipe (PCCP) were rehabilitated during a
refueling outage. As a result of predictive
maintenance practices this facility is able
to evaluate, prioritize, plan, and imple-
ment repairs before leakage or structural
issues challenged operations.
Cooling Towers
Original construction practices, poor
quality construction materials, harsh
environmental condition exposure and
changes to process streams can culmi-
nate in failures to cooling towers struc-
tural components. Regardless of whether
the cooling tower is natural or mechani-
cal draft, deterioration is predictable and
preventable with regularly scheduled in-
spections and maintenance. Potential re-
inforced concrete maintenance issues on
Cooling Towers include:
Cracks in the reinforced concrete
walls and base slab
Adhesion/cohesion joint sealant
failures
Embedded waterstop leakage
Expansion joint deterioration and
leakage
Mechanical penetration leakage
Anchor bolt and fastener corrosion
Degraded foundation support for the
This figure shows a graph of the cost of repair versus time. This figure
illustrates the three observed phases describing the natural evolution of the
structural and civil infrastructure deterioration process and the influence of
maintenance on this process:
1) PredictiveMaintenance Phase: In this phase, the owner may spend a fixed
annual maintenance cost to assess conditions and install systems such as
protective coatings to slow down the deterioration process. Investment in
the predictive maintenance phase will extend the duration of the phase
over time by slowing or mitigating the root cause of deterioration if
identified early.
2) Reactive Maintenance Phase: In this phase, the deterioration mechanisms are
in place, but will not be visible in the early stages. With many types of structural
and civil infrastructure, deterioration rates are rapid and irreversible.
3) Replacement Phase: In this phase, “wholesale” deterioration occurs throughout
the structure at such a rapid rate that repair costs may exceed the costs of
replacing the entire structure. However, total replacement of the structure may
not be an option because of interruption to the function of the structure.
