MCC's

Motor Control Centers (MCCs) are vital to the safe operation and control of nuclear power plants.  A significant and growing problem within the global nuclear industry is the aging of MCC components.  Obsolescence of various components within the MCCs such as molded case circuit breakers, starters, relays, heaters, contactors, etc. are impacting the reliability of MCCs to perform their intended function.

Many OEMs have sold off product lines or merged with others companies.  This has complicated the procurement of replacement parts needed to maintain reliability of MCCs.  The combination of aging installed equipment, component obsolescence and surveillance testing (required by technical specifications) is forcing many plants to aggressively address MCC refurbishments or face unplanned outages due to unavailability of critical motors.

NLI offers replacements for most legacy MCCs.  All MCC cubicles, or “buckets,” are designed and fabricated by NLI.  NLI has supplied thousands of MCC replacement cubicles for ITE 5600 and 9600 Series, GE 7700 Series, Westinghouse  5 Star and Type W Series, Cutler Hammer F-10, 9800 Series and Cutler-Hammer DC cubicles.

Replacement requires identification of suitable replacements, design drawings, dedication, qualification, layout design and fabrication.  Many components, and in some cases entire cubicles, are no longer available or not supported by the OEM.

NLI can install any manufacturers’ components into the cubicles based on the original design space requirements.  The larger OEMs will not build an MCC with another OEM’s components.  Regardless of manufacturer, every component is 100% dedicated to EPRI NP-5652 Method 1, Special Tests and Inspections, prior to installation in the cubicle.

NLI offers a variety of MCC services from full replacement to refurbishing existing components.  NLI also retrofits existing MCCs by replacing stabs, latches, and structural components for better seismic rigidity.  NLI maintains a large selection of OEM motor control centers, which are used both for seismic qualification and to ensure proper fit.

Many standard OEM designs will not pass rigorous nuclear seismic testing requirements.  When OEM centers are specified, NLI designs and installs special braces and supports prior to performing qualification testing.

NLI has qualified MCC cubicles for both mild and harsh environments.  All qualification is performed to the plant specific requirements in accordance with IEEE Standards 344 and 323.  NLI uses Rockbestos Firewall III SIS type wire for all control wiring qualified in accordance with IEEE Standard 383.

NLI supplies the following documentation with each MCC cubicle order:

  • Layout drawings for each type of cubicle
  • Wiring diagrams
  • Bill of Materials (BOM)
  • Qualification Report
  • Certificate of Conformance
  • All engineering, fabrication, testing, and documentation generation is performed at the NLI Fort Worth, TX corporate facility.