All repairs are completed under our QA program and ensure valves meet all OEM specifications. NWS provides complete repair services for all types of safety/ relief valves, including:
Valve Repair
  • Dresser/ GE-Consolidated - PSVs, MSSVs, PORVs and ERVs

  • Crosby - PSVs, MSSVs, MSSRVs, and CARVs

  • ​Target Rock - Pilot operated 2 and 3-stage MSSRVs

  • Dikkers - MSSRVs

  • Other OEMs - Balance of Plant Steam/ Water/ Air/ Valves

Spring Testing
NWS records spring dimensions as part of each repair. This includes measurements of free height, squareness, and parallelism. In addition, NWS also offers spring rate testing, and recommends it as an extra assurance that the spring has not degraded from years of service. Using our calibrated spring rate test machine, we can verify that the spring rate is within OEM specifications.
Disc Oxidation
Disc oxidation is an additional, optional repair process for some MSSVs. This process minimizes the risk that the disc seat will stick to the nozzle seat during service. After disc seats have been lapped and polished, the discs are placed into our temperature controlled, high-pressure oxidation chamber and exposed to high pressure steam for a specified period of time. Process data (i.e. temperature and pressure) are recorded using our specially calibrated instruments. Upon completion of this process, an oxidation layer is present on the disc seat.
 
Nozzle Passivation
Nozzle passivation is an additional, optional repair process for some MSSVs. This process minimizes the risk that the nozzle seat will stick to the disc seat during service. After nozzle seats have been lapped and polished, the nozzles are submerged in a chemical mixture for a specified period of time. Upon completion of this process, an oxidation layer is present on the nozzle seat.

131 Venture Boulevard, Spartanburg, SC 29306     Tel: (864) 587-7001      Fax: (864) 587-9005

Serving Nuclear Power Since 1996