PLANT LIFE EXTENSION OF

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Department of Civil Engineering, University of
Toronto

• PLANT LIFE EXTENSION OF
• CONCRETE NGS STRUCTRUES
• S. A. Sheikh
• F. J. Vecchio

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PLANT LIFE EXTENSION OF CONCRETE NGS STRUCTRUES
CHALLENGES AHEAD
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Electricity Sources in Ontario

• Nuclear power stations provided 51 of Ontarios
  total electrical energy in 2005.

Source Independent Electricity System Operators
(IESO) 2005
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Service Profile of 20 NGS Facilities
2006
Source OPG and International Atomic Energy
Agency PRIS
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NGS Units Nearing End of Service Life

• Typical service life of NGS is 30 to 40 years
  current stock of NGS stations is nearing end of
  expected service life.
• Many existing power facilities are ageing, and
  80 will need to be refurbished or replaced over
  the next 20 years.
• Between 2010-2025, Bruce, Darlington and
  Pickering Stations will come to the end of their
  service life

Planning Assumptions Regarding Nuclear
End-of-Service Dates
Total MW
Source OPA with advice from IESO and Nuclear
Operators
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New NGS Plants
PLANNING FOR THE FUTURE

• It takes up to 20 years to receive approval,
  plan, design, build, commission, and bring
  on-line a new NGS plant.

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Future Energy Sources
Options For Meeting Future Demands

• Construction of New NGS Plants
• Refurbishment of Current NGS Plants
• Alternate energy sources Wind, Solar,
  Hydroelectric
• Conservation
• Source OPA and CERI

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The Concrete Connection

• Concrete structures typically account for a large
  proportional of the capital cost and construction
  time of NGS plants.
• Up to 25 of total construction cost.
• Reactor buildings, vacuum buildings, manifold
  ducts, intake and discharge ducts, spent fuel
  bays, transportation casks, and underground
  repositories, are key components.

Source OPG
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Refurbishment of Units

• Concrete structures will require
• refurbishing or rehabilitation due to
• Normal age-related deterioration.
• Accidental damage or deterioration due to
  prolonged downtimes.
• Changes in function requirements.
• Compliance with new, more stringent design codes.

National Building Code of Canada 2005
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New Security Threats
Design Concerns

• Structural design criteria must be reconsidered
  in light of new security threats.
• Extreme loading conditions may include
• blast
• impact
• high temperatures.
• Components of existing plants may require
  modification.

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CURRENT RELATED RESEARCH
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Joint Research Projects

• Selected examples of previous collaborative
  research projects
• NSERC Strategic Research Grant (1991-1993)
• Vecchio Ontario Hydro
• Effects of Elevated Temperatures on Slab
  Structures
• COG Project (2000-2002)
• Vecchio Kinectrics
• Structural Analysis of Concrete Members at
  Elevated Temperatures
• ISIS Canada Research Grant (2001-2004)
• Sheikh Kinectrics
• Testing of Carbon FRP Fabric under High
  Temperature, Gamma Radiation, and other Exposure
  Conditions
• ISIS Canada-MTO (2005-2008)
• Sheikh Kinectrics
• Freeze -Thaw Effects on FRP-Concrete Composites
  under Sustained Loads

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Advanced Analytical Tools

• VecTor Programs Based on MCFT F.J. Vecchio
• The Modified Compression Field Theory (MCFT) is
  a widely accepted model for representing the full
  behavioural response of reinforced concrete
  elements. The paper written presenting the theory
  is the most frequently cited reference in the
  history of the American Concrete Institute
  Journal.
• A full range of nonlinear finite element
  analysis (NLFEA) programs for specialized
  application to reinforced concrete structures has
  been developed. The constitutive models and
  analysis algorithms incorporated into the VecTor
  suite of programs result in accurate and
  numerically stable solutions that are able to
  follow response to well beyond post-peak levels
  and high damage conditions. Current work is in
  applications to rehabilitated structures, and in
  modelling of structures subjected to extreme
  loads including blast and impact.
• Analytical Models for Seismic Resistance of
  Concrete Structures by S. A. Sheikh
• Models developed for the response of confined
  concrete under large inelastic deformations have
  been widely used by researchers and designers
  around the world and have influenced current
  provisions of modern design codes.

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Rehabilitation of Concrete Structures

• FRP Application in NGS (Sheikh)
• In addition to normal extreme environmental
  exposures, the repair materials used in
  containment structures should pass an
  OPG-required 250kGy gamma radiation test.
• (1 Gy 1 joule per 1 kg mass of specimen).
• OPG also requires that the materials used in
  nuclear power plants be able to endure the Loss
  of Coolant Accident (LOCA), which involves a
  sudden temperature change.
• Comprehensive experimental research programs
  have addressed these concerns.
• Behaviour of Rehabilitated Structures (Vecchio,
  Sheikh)
• Material models and analytical techniques, for
  simulating the behaviour of retrofitted or
  rehabilitated structures, are being developed and
  implemented into advanced software. Particular
  attention has been devoted to modelling the
  response of FRP-repaired structures.

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Nuclear Power Generation Plant Environments

• Typical and Possible Exposures
• An operating temperature of 40oC
• Gamma radiation in reactor building
• Loss of Coolant Accident (LOCA) in reactor
  building and generator building

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FRP Specimens Exposed to Gamma Radiation
Ontario Power Generation (OPG) requires that the
material used in the containment structures
should pass a 250kGy gamma radiation test. (1 Gy
1 joule per 1 kg mass of specimen)
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Loss of Coolant Accident (LOCA) Scenario
OPG requires that the material used in the
nuclear power plants is able to endure the Loss
of Coolant Accident (LOCA), which is a sudden
temperature change shown in the graph below
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FRP Specimens Exposed to the Loss of Coolant
Accident (LOCA) Scenario
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FRP Coupons Exposed to Various Environments
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FRP Coupons Response to Impact Loading
Impact
Strain Rate 40/sec
CFRP
Strain Rate 70/sec
Q. Static
GFRP
CFRP
GFRP
Strain Rate 0.27/sec
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Extreme Loads

• Impact
• Analytical Program VecTor2 is being modified for
  the consideration of high dynamic loads,
  including blast, impact and ground excitations.
• Experimental A series of tests on shear-critical
  large scale beams and FRP specimens were
  conducted under impact loads. Test results will
  be used to formulate improved behaviour models
  and refine analytical procedures.
• Test Facilities The Structures Laboratories are
  being renovated for the installation of a 8.0M
  impact test facility.

• Blast
• Studies have been undertaken to better quantify
  time-pressure histories for blast loads on
  structures. Program VecTor-Blast was formulated.
• High Temperature
• Time-dependent heat flow analysis capabilities,
  and improved consideration of temperature-dependen
  t properties of concrete and reinforcement, are
  being implemented into analysis programs.
• Earthquake
• Theoretical and experimental studies are ongoing
  to develop improved seismic analysis and design
  procedures, and to develop rehabilitation methods
  for seismically damaged or deficient structures.
  Experimental and analytical studies are planned
  to develop new innovative seismic protection
  systems for highly enhanced seismic response
  (Isolation, Energy Dissipation Devices)

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High Impact Test Facility under Construction
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THANK YOU FOR YOUR ATTENTION