Callaway Emergency Diesel Generators

Callaway Emergency Diesel Generators

Location: Fulton, Mo.

Client: AmerenUE

Completion Date: December 2010

Burns & McDonnell provided professional services to the Callaway Nuclear Plant to design an alternate emergency power system consisting of four 2-megawatt (MW) diesel generators and an additional off-site 13-MVA co-op transformer. Burns & McDonnell provided the initial conceptual design and study options leading to the final design implementation. For the final design, Burns & McDonnell was responsible for site layout, permitting assistance, shared project management, nuclear design change disposition development, detailed design, safety-related core drill and missile shield design, digital control software configuration development, and construction field support.

  • Engineering study
  • Site layout/design
  • Permitting analysis
  • Project management
  • Design change package
  • Detailed design
  • Safety-related core drill and missile shield design
  • Software configuration package
  • Field support

The Mitigating Systems Performance Indicator (MSPI) is an indicator for one of the seven cornerstones of the Nuclear Regulatory Commission (NRC) Reactor Oversight Process (ROP). Driving the performance is a MSPI that tracks the performance of the emergency AC power system at Callaway.

The Unavailability Index (UAI) for the system had noticeably increased. Specifically, “Failures to Run” on the emergency diesel generators (EDGs) were the main contributors. Further increases of the UAI would produce increased regulatory response.

The installation of the alternate emergency power system (AEPS) diesel generators improved Callaway's ability to mitigate a station blackout (SBO). The AEPS generators provide an alternate source of power during an SBO that is diverse from the EDGs and off-site sources. The improvement positively affected Callaway's Probabilistic Risk Assessment (PRA) and, in turn, the UAI. A PRA improvement created safety margin for the MSPI and reduced the intensity and frequency of the regulatory inspections prompted by EDG problems.

A diesel generator bank was added to a remote location 1.5 miles from the Callaway site.  The diesel generator bank was interconnected to a new transformer at that location to supplement the new off-site power source. Underground cables were direct buried from the off-site location to a spare transformer at the plant site. The new off-site power source connected to the existing site 4.16-kV safety-related AC busses via spare qualified isolation breakers and relays. The off-site diesels start on a loss of both safety-related emergency diesel generators and a loss of off-site power. The feeder breakers to the safety-related busses from the non-safety AEPS source are manually closed by plant operations when needed. Safety-related core drills and missile shield protection was required for cable penetrations through the Callaway control building walls.

  • Four 2-MW 13.8-kV Caterpillar diesel-powered generators (non-safety related)
  • Remote location (1.5 miles off-site)
  • Lowered MSPI PRA for emergency AC power system
  • Digital programmable logic control for diesels and switchgear
  • Connection to existing site, including 4.16-kV safety-related busses (dead bus connection)
  • 13.8-kV/4.16-kV switchgear
  • Coordination with 13-MVA co-op off-site transformer
  • Aggressive design schedule, worked by concurrent design/construction procedures