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FlowserveFlowserveNuclear Primary Pump Seals - N-Seals

Nuclear Primary Pump Seals - N-Seals

BRAND: Flowserve

The result of years of research, thousands of hours of rigorous testing and decades of primary pump application experience, the Flowserve N-Seal primary pump seal represents the nuclear industry’s most advanced mechanical seal technology. With each of three stages capable of sustaining 100% system pressure, the N-Seal has successfully provided proven service life and fail-safe redundancy in Flowserve Byron Jackson® primary coolant pumps for years.


  • Power

industry sectors

  • Nuclear

ASME Section III, Class I

Operating Parameters
  • Discharge pressures to 170 bar (2500 psi)
  • Temperatures to 300°C (580°F)
  • Speeds to 1800 rpm
Design Range

Size Range: 6" to 9.62" shaft size

Features & Benefits
  • Unique cartridge construction simplifies installation, enables more accurate seal setting, and keeps associated costs low.
  • Triple redundant seal design mirrors existing seal system parameters.
  • Each of the three stages can handle 100% of the system pressure.
  • Hydrodynamic seal face technology outperforms hydrostatic designs with dramatically improved reliability and running periods.
  • Three different seal face lift designs are available to ensure non-contacting faces over a broad operating range.
  • Pressure is automatically redistributed to the remaining two stages in the event of a stage failure, allowing the plant to complete the fuel cycle. Interchangeability of stage components enables spare parts inventories and carrying costs to be reduced.
  • Large axial travel capability maximizes operating life; sealing integrity maintained through all plant transient scenarios.

Nuclear Seal


Flowserve has developed an interactive animation to familiarize users with the seal’s key design attributes that contribute to its remarkable performance, safety and reliability. Users can navigate through a variety of highly detailed animations, cross-sectionals, and images, all with extensive information.

Download now. This may take 2-3 minutes. IT support may be needed to download and/or install.

Users will:

  • Learn how N-Seal’s multiple identical stages create a safety margin through redundancy
  • Find out how  N-Seal automatically redistributes system pressure in the event of a stage failure
  • Hear about how N-Seal’s cartridge construction results in low conversion and installation costs
  • Learn how hydrodynamic seal face technology dramatically improves reliability and running periods
  • See how the state-of-the-art abeyance backup seal provides near-zero leakage protection that exceeds Station Blackout regulatory requirements
  • Discover how N-Seal can help station operators transition from preventive to predictive maintenance regimes
  • Learn about the extensive performance and endurance testing N-Seal has undergone to ensure fail-safe operation
  • Find out how Flowserve can help with project services, testing, installation, training and aftermarket support

N-Seal interactive tool




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