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Failure Analysis of Reactor Cooling Pump Mechanical Seals

Diagnosis and correction of mechanical seal problems - projects by Kinectrics’ materials specialists.

Leakage in Mechanical Seals

Mechanical seals employed in reactor recirculation pumps and reactor coolant pumps provide a controlled leakage barrier between the pressure boundary stationary, and the rotating parts that seal the light and heavy cooling water used in US and Canadian primary coolant systems.

Leakage through these mechanical shaft seals is restricted to flow rates set by administrative limits and technical specifications.  Excessive leakage to collection can result in costly forced outages and outage delays required for seal replacement.

Kinectrics’ Solution

In addition to supporting root cause investigations of mechanical seal problems, Kinectrics’ materials engineers provide on-site inspection services and laboratory forensic testing. 

Laboratory testing is performed to compare and contrast the performance of different seal designs and materials operating in similar environments.  Active samples are examined in Kinectrics’ Radioactive Materials Laboratory, often in collaboration with other industry experts.

Metallic and elastomeric components from the following reactor coolant pump and mechanical seal types were previously examined by Kinectrics:

  • CANDU Shutdown Cooling (SDC) Pumps
    • AECL CAN6 seals
    • Flowserve (formerly Durametallic) HPTO Seals
  • CANDU Primary Heat Transport (PHT) Pumps
    • AECL CAN8 seals
  • PWR Reactor Cooling Pumps (RCP)
    • Westinghouse Model 93A1 Cartridge Seals