Startup/Wide Range Detectors (SRNM/WRNM)

GE designed its Reuter Stokes wide range detector (WRNM) to perform the functions of both the source range monitor (SRM) and the intermediate range monitor (IRM) during reactor startup. Our WRNM detectors operate in a dry tube inside the reactor core. The detectors are permanently fixed within the reactor core—even at full-power operation—throughout the entire fuel cycle.

Features and Benefits
  • Single, stationary sensor replaces moveable SRM and IRM instrumentation eliminating mechanical drive system
  • Hands-off operation
  • Continuous power indication for entire startup period, requiring no range selection switches
  • Long-life detector
  • Nominal lifetime is 1.2 x 1022 nvt, but operational experience at some power plants has exceeded an average life of 1.7 x 1022 nvt (or approximately 10 full-power years)
  • Reduces undervessel activities, maintenance and exposure during outages
  • Environmentally and seismically qualified, meeting requirements of U.S. NRC Reg Guide 1.97 for post-accident monitoring

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