Summer Co-op Experience: OPG

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Summer Co-op Experience OPG
Aditi Garg
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Darlington Nuclear G.S
Located in Bowmanville, ON
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About the plant

• 4-unit station with a total output of 3,524
  megawatts (MW)
• 20 per cent of Ontarios electricity
• Tritium Removal Facility
• extracts tritium from heavy water

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COMPONENTS AND EQUIPMENT

• Electrical and IC
• Major Components
• Mech Rotating Equipment
• Valves

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Major Components

• Fans
• Compressors
• Pumps
• Steam Generators (Boilers)
• Feeders
• Reactor Maintenance

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Inside the plant
Main Boiler Feed Pump
Turbine Hall
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Projects

• Critical equipment and Critical spares List
• Root cause analysis of the seal failure
• Transient monitoring for Feeders
• Plant walk-down

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Transient monitoring for Feeders

• CNSC ?Keep track of transient events that have
  occurred in each unit.
• For all nuclear class system piping
• Plant Information System (PI)
• Temperature, pressure, Power, etc. for all
  planned and forced outages

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Feeder thinning

• reduction in pipe wall thickness of the
  outletfeeders
• High pH? dissolves pipes reduces thickness
• The cause of feeder thinning is flow accelerated
  corrosion (FAC).
• poor design defects, poor chemistry controls and
  high temperature and pressure.

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Face of the CANDU reactor
The face of a CANDU reactor (under
construction).Some feeder pipes can be seen to
the right of the reactor face.
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Flow Accelerated Corrosion (FAC)

• motion of a corrosive fluid and a metal surface.
• Outlet feeders
• Dissolution of magnetite (Fe3O4)
• Affects carbon steel components
• High flow and specific water chemistry
  conditions.
• Resulted in excessive thinning and failure of
  feedwater lines

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Reduce thinning

• Outlet feeders
• Injected by Titanium Dioxide
• Uniform coating inside pipe to reduce thickness
• Fe3O4 ? Dissolves with high temperature and
  pressure (pH gt10.6)
• Chemistry pH 10.1- 10.4 ? rate of solubility is
  low

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Feeder Integrity Project

• The Project is actively pursuingmeans to
• Extend the life of the feeders
• Developing tooling for eventualfeeder
  replacement
• Further developing pipe inspection techniques

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Root Cause Evaluation

• Second Stage Reheat Pumps
• Seal temperature was high above the alarm set
  point
• Perform a failure modes analysis of the
  historical seal failures
• Review modification packages and make changes to
  design
• Identify technical and human performance related
  root cause

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Thank you!!