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Sempell Nuclear Model MFDCV Main Feedwater Damped Check Valve
Sempell Series MFDCV Damped Main Feedwater Check Valve
Developed to protect the piping system after a pipe break in the feedwater line of a nuclear power plant.
Sempell Nuclear Model MFDCV Main Feedwater Damped Check Valve


Sizes NPS (DN)
Up to 18 (450)
lass 1500 / PN250
up to 300°C
Body material:
A105 (1.0460) and S/S


  • One–piece, compact block design with forged or cast body thus not presenting any seismological safety problem. The connection of the damping chamber with the main valve body is integrated into the cylinder, thus no external equalizing or balancing pipe is necessary.
  • Simple, robust design with only a few moving parts, which leads to low maintenance requirements and a small stock of spares. Internal components can be removed from the body as a single unit.
  • Guiding of the piston and the disc can be replaced, while the valve body remains in the pipeline and is not subject to any maintenance.
  • The internal design of the valve is flexible, optional fixed closing time or customized closing behavior is possible. The damping of piston ensures that the high pressure transients in feedwater lines are eliminated as required by specifications of the specific reactor design.
  • Optimized disc design for stable open position at low flows to ensure plant operation within a wide load range.
  • Cobalt–free hardfacing for applications in contact with primary circuit media on request, since the radioactivity in nuclear power stations is primarily caused by the Co󈞦 and Co–60 cobalt isotopes.
  • Inductive position indicator on request available, thus not requiring penetration of the pressure retaining boundary.
  • Optimized for low pressure loss to ensure plant efficiency.
  • Full scale tests executed in test loop HDR Kahl DN 350 for verification of fluid dynamic behavior.
  • Seismic shake table test acc. to IEEE 344 executed for different designs.