Predictive
Maintenance
for
Infrastructure
By Brent Anderson and Tom Kline,
STRUCTURAL TECHNOLOGIES.
Brent Anderson
Brent Anderson, P.E. is the Moisture
Control Solutions Team Leader at
STRUCTURAL TECHNOLOGIES. Brent
provides forensic foundation engineering
for concrete problems, including
cracking, deflection, soil, and settlement,
along with water leakage problems in
roofs, cavity walls,
air/vapor barriers,
and floors. He is
an expert in below-
grade and plaza
deck waterproofing
products, chemical
grouting with
urethanes, micro-
fine cements,
bentonites,
acrylamides,
acrylics, and
epoxies.
Jorge Costa, P.E., Vice President –
Corrosion Solutions Team and Anna
Pridmore, PhD, Vice President - Pipe
Solutions also contributed to this article.
The nuclear industry is a leader in
implementing proactive maintenance
programs for process equipment.
Repairs, maintenance, and replacements
are aggressively addressed because there
is a direct correlation to production and
profitability.
Civil and structural infrastructure
that supports process equipment is often
given a much lower priority and often not
budgeted until operability is jeopardized.
Environmental factors not considered in
the original design process often nega-
tively impact the service life of civil and
structural infrastructure. The principles
of predictive maintenance can prevent
or rehabilitate infrastructure challenges
before they spread to the critical process
equipment they support.
Asset Predictive
Maintenance Program
The
United
States Nuclear Reg-
ulatory Commission
(NRC) published the
“Maintenance Rule”
on July 10, 1991, as
10CFR50.65,
Re-
quirements for Mon-
itoring the Effective-
ness of Maintenance
at Nuclear Power
Plants
. 10CFR50.65
requires nuclear pow-
er plants to, “moni-
tor the performance
or condition of structures, systems, or
components, against licensee-established
goals, in a manner sufficient to provide
reasonable assurance that these struc-
tures, systems, and components…are
capable of fulfilling their intended func-
tions.”
Regulatory Guide 1.160,
Monitoring
the Effectiveness of Maintenance
at Nuclear Power Plants
, provides
information to licensees on what the NRC
feels is an acceptable approach to meet
the requirements of 10CFR50.65 and
encourages the use of reliability-based
methods for developing maintenance
programs.
Predictive
maintenance
programs createa systematicandproactive
approach to identifying, prioritizing, and
repairing assets throughout a facility
or for a particular unit or structure. A
program should incorporate:
Condition assessments
Determination of the probable
cause(s) of deterioration/distress
Nature and severity of deterioration/
distress
Realistic design and performance
objectives
Estimated service life of the repaired
structure
Selection of appropriate monitoring,
rehabilitation and maintenance
methods
Preparation of engineering design
and specification documents
Rehabilitation and maintenance
programs
Monticello Nuclear Generating
Plant, located in Minnesota incorporates
predictivemaintenance practices into their
corporate culture. Predictive maintenance
tools used on process equipment indicated
weaknesses in a pump support system.
Subsequent
investigations
revealed
cracks and voids in the grout between the
pump’s foundation and the supporting
steel plate. Repairs were able to be
implemented while the plant remained
in operation and before any challenges to
performance spread to operating process
equipment.
Some other unique infrastructure
components and examples below
highlight the benefits of predictive
maintenance.
Reinforced Concrete
Nuclear plants have reinforced
concrete structures that are vital to process
equipment performance and functionality.
Corrosion diminishes structural integrity
and may affect plant operations if
not addressed promptly. Corrosion in
concrete is the electrochemical reaction
of the reinforcement steel exposed to
a corrosive environment resulting in
its progressive degradation or failure,
commonly seen as rust. In reinforced
concrete, where steel is embedded below
the surface, the symptoms of corrosion
may not be noticed immediately.
Contaminants can permeate through
the concrete porosity reaching the
embedded rebar and initiating corrosion.
Cracking, spalling, and delamination
are outward signs of a serious corrosion
problem. Corrosion of reinforcing steel in
an intake structure caused an incident at
an East Coast nuclear facility. Extensive
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NuclearPlantJournal.com Nuclear Plant Journal, March-April 2015
