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Instrumentation & Controls

Instrumentation & Controls

Analog Systems

Curtiss-Wright recognizes the elegant but secure simplicity that most nuclear plant safety systems use: they monitor a small number of inputs and produce a small number of outputs, using simple functions for efficient process control and safe shutdown when required. A large portion of these hyper reliable systems were built back in the 70s and 80s, meaning that many plants are reaching the end of these systems reliable lives and are choosing to replace entire systems due to obsolescence issues or new design requirements.

Seeing the need for both partial and total replacement of analog safety systems, Curtiss-Wright has developed and maintained our Analog Safety Systems solutions to meet every potential plant need. Both the Modern Analog Safety System (MASS) and Heat Trace Control System (HTCS) mirror the best qualities of older analog systems while implementing the benefits of modern technologies, meeting any need ranging from legacy to modern systems.

General Scope

  • Easy to Understand – Curtiss-Wright’s Analog Safety Systems are partitioned into simple modules making them easy to read and interpret
  • Easy to License – The NRC reviews new analog systems to the same criteria as the original analog systems, meaning our systems have no DI&C ISGs, no complex submittal schedule, and no uncertainty as to needs
  • Easy to Test – Both MASS and HTCS have built-in testing and calibration functions
  • Lower Cost - Reduced licensing cost paired with modern manufacturing techniques make Curtiss-Wright’s Analog Safety Systems a lower cost alternative to costly digital solutions
  • Long, Obsolescence Resistant Life – Beyond being both stable and backwards compatible, Curtiss-Wright will always be able to make analog modules with analog components – there are no microprocessors or families of digital chips to go obsolete
  • Cyber Secure - An analog system is not vulnerable to cyberattack – there’s no software to attack

Modern Analog Safety System (MASS)

  • Contains many simple to understand, easy to use modules, including input, summer, multiplier, divider, square root extractor, alarm, and output modules
  • Overall system design, simple vs. complex requirements
  • Modern surface mount technology allows circuit board production at a fraction of the cost of the older, through-hole technology
  • With a 0.05% drift over 120 days, MASS is extremely stable and highly reliable
  • Recalibration of MASS are few and far between, saving time and maintenance costs
  • MASS has loop accuracies of less than 0.5%, about five times more accurate than typical legacy systems
  • Built-in test equipment for quick, easy testing, allowing online testing of almost all functions
  • Available in 2 easy to set up configurations, both of which are tailored to customer monitoring and diagnostic needs
  • Meets all applicable standards, including:
    • IEEE 338
    • RG 1.100 / IEEE 344
    • RG 1.197 / IEEE 497
    • IEEE 352 and 577
    • RG 1.53 / IEEE 379
    • RG 1.180
    • IEEE 383
    • RG 1.75 / IEEE 384
    • E 279 and 603
    • RG 1.89 / IEEE 323

Heat Trace Control Systems (HTCS)

  • Built of 3 easy to use modules: the Controller Module, the Meter Module, and the Power Module
  • Simplified analog design reduces licensing and manufacturing costs
  • Designed to control multiple runs of safety-related heat tracing in nuclear power plants
  • Each heater is matched to a Controller, which monitors, maintains and, the case of an emergency, shuts off the heater
  • Multiple Controllers connect to a Meter module, which monitors and shares data from the Controllers, allowing for temperature and set point monitoring and adjustment
  • The Meter Module includes an easy and accessible methods for calibration using a local source
  • Additional Specifications:
    • Controller Input: PT100 RTD (Others available)
    • Controller Tempurature Range: 10°C to 230°C
    • Controller Accuracy: ± 1.5°C / ± 2.7°F
    • Controller Response Time: < 1 second
    • Meter Display Accuracy: ± 1.0°C / ± 1.8°F
    • Heater Power: 115 Vac, 0.4A to 15 A
    • Heater Power Relay: Solid State, NO
    • Heater Cutoff Relay: Mechanical, NC
    • Environmental Qualification: IEEE-323 mild environment
    • Seismic Qualification: IEEE-344
    • EMC Qualification: EPRI TR-102323
    • Input Power: 115 Vac ± 10%, 60 Hz ± 1 Hz