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Summer Co-op Experience: OPG. Aditi Garg. Darlington Nuclear G.S. Located in Bowmanville, ON. About the plant. 4-unit station with a total output of 3,524 megawatts (MW) 20 per cent of Ontario’s electricity Tritium Removal Facility extracts tritium from heavy water.
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Summer Co-op Experience: OPG Aditi Garg
Darlington Nuclear G.S Located in Bowmanville, ON
About the plant • 4-unit station with a total output of 3,524 megawatts (MW) • 20 per cent of Ontario’s electricity • Tritium Removal Facility • extracts tritium from heavy water
COMPONENTS AND EQUIPMENT • Electrical and I&C • Major Components • Mech & Rotating Equipment • Valves
Major Components • Fans • Compressors • Pumps • Steam Generators (Boilers) • Feeders • Reactor Maintenance
Inside the plant… Main Boiler Feed Pump Turbine Hall
Projects • Critical equipment and Critical spares List • Root cause analysis of the seal failure • Transient monitoring for Feeders • Plant walk-down
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
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.
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.
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
Reduce thinning • Outlet feeders • Injected by Titanium Dioxide • Uniform coating inside pipe to reduce thickness • Fe3O4 Dissolves with high temperature and pressure (pH >10.6) • Chemistry: pH 10.1- 10.4 rate of solubility is low
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
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