Global Leader in Commercial Nuclear Safety Systems
Leonardo DRS carries forward a storied lineage in the field of nuclear instrumentation and control (I&C) systems, with its origins deeply rooted in the company formerly known as Consolidated Controls, Inc. In 2008, following its acquisition by Finmeccanica (now Leonardo), Consolidated Controls evolved into what is known today as Leonardo DRS Nuclear Instrumentation and Control. This transformation marked a new chapter in the company’s history, while still upholding a legacy that began in 1958 from its headquarters in Danbury, Connecticut.
With over 70 years of innovation, Leonardo DRS has been a trusted provider of Class 1E safety-related I&C solutions for both naval and commercial nuclear markets. From pioneering the I&C design for the USS Nautilus (SSN-571) to supporting every nuclear-powered warship since, our expertise is deeply embedded in national defense. Expanding into the commercial nuclear sector in the 1970s, we continue to engineer resilient, reliable systems for the most demanding environments worldwide.
Over the last 50 years we have installed safety control systems in more than 30 commercial nuclear power plants
Leonardo DRS has a global installed base of I&C systems that include analog control systems, discrete logic systems, and microprocessor-based systems. These systems have proven track records of performance, reliability and quality.
- Analog Upgrade of Engineered Safety Features Actuation System (ESFAS)
- Analog Upgrade of Load Shedder and Emergency Load Sequencer (LSELS)
- Anticipated Trip Without Scram (ATWS)
- Emergency Load Sequencer (ELS)
- Emergency Diesel Generator Controls
- Emergency Power Sequencer Subsystem (EPSS)
- Engineered Safety Features Actuation System (ESFAS)
- Load Shedder and Emergency Load Sequencer (LSELS)
- Main Steam and Feedwater Isolation System (MSFIS)
- Main Steam Isolation Valve (MSIV) Electronic Logic System
- PLµS 32 Plant Digital Control System
- Safeguard Load Sequencing Systems (SLSS)
- Safety Features Actuation System (SFAS)
- Safety Features Sequencer
- Safety Related Auxiliary Relay System
- Safety Related Isolation Cabinet
- Safety Related Isolation Panels
- Solid State Control System (SSCS)
- Solid State Interposing Logic System (SSILS)
- Steam and Feedwater Rupture Control System (SFRCS)
- Steam Generator Level Instrumentation Cabinet (SGLIC)
Design Services
Nuclear I&C System Refresh
No Forced Product Retirement is a key customer service philosophy at Leonardo DRS Nuclear I&C. As such, Leonardo DRS Nuclear I&C has the processes and personnel in place to provide reverse engineering services for both analog and digital based systems, providing a technology refresh for legacy systems.
Leonardo DRS Nuclear I&C has a detailed Counterfeit Electrical, Electronic and Electromechanical (EEE) Parts Control Plan used for risk identification, mitigation, disposition, detection and avoidance techniques, and for reporting of suspect or confirmed counterfeit EEE parts and/or assemblies containing such EEE parts. This plan is in compliance with:
- SAE AS5553D; Counterfeit Electrical, Electronic and Electromagnetic (EEE) Parts Avoidance, Detection, Mitigation, and Disposition
- SAE ARP6328; Guideline for Development of Counterfeit Electronic Parts: Avoidance, Detection, Mitigation and Disposition Systems
When providing replacement components, Leonardo DRS Nuclear I&C analyzes the original equipment specification requirements, identifies any obsolete sub-components, devises component replacement strategies, and implements engineering hardware solutions to ensure that the replacement components meet or exceed the form, fit and function of the original components.
- Design Change/Update
- Repair/Refurbish
- Reverse Engineering/Retrofits
- Component Verification Plans (Used for Parts from Unauthorized Distribution Channels)
- Component Substitution
Commercial Grade Dedication
Per EPRI NP-5652 and TR-102260, Commercial Grade Dedication (CGD) is “an acceptance process that is undertaken to provide reasonable assurance that a commercial-grade item to be used as a basic component will perform its intended safety function and, in this respect, is deemed equivalent to an item designed and manufactured under a 10CFR50, Appendix B QA program.”
Leonardo DRS Nuclear I&C has a detailed Counterfeit Electrical, Electronic and Electromechanical (EEE) Parts Control Plan used for risk identification, mitigation, disposition, detection and avoidance techniques, and for reporting of suspect or confirmed counterfeit EEE parts and/or assemblies containing such EEE parts. This plan is in compliance with:
- SAE AS5553D; Counterfeit Electrical, Electronic and Electromagnetic (EEE) Parts Avoidance, Detection, Mitigation, and Disposition
- SAE ARP6328; Guideline for Development of Counterfeit Electronic Parts: Avoidance, Detection, Mitigation and Disposition Systems
When providing replacement components, Leonardo DRS Nuclear I&C analyzes the original equipment specification requirements, identifies any obsolete sub-components, devises component replacement strategies, and implements engineering hardware solutions to ensure that the replacement components meet or exceed the form, fit and function of the original components.
- Design Change/Update
- Repair/Refurbish
- Reverse Engineering/Retrofits
- Component Verification Plans (Used for Parts from Unauthorized Distribution Channels)
- Component Substitution
Obsolescence Management
Leonardo DRS Nuclear I&C provides services to support plant personnel with replacement components for those parts that are no longer available in the marketplace or are no longer supported by the Original Equipment Manufacturer (OEM). Replacement components are procured, designed, manufactured, tested and inspected to ensure that the components meet or exceed the form, fit and function of the original components.
Leonardo DRS Nuclear I&C has a detailed Counterfeit Electrical, Electronic and Electromechanical (EEE) Parts Control Plan used for risk identification, mitigation, disposition, detection and avoidance techniques, and for reporting of suspect or confirmed counterfeit EEE parts and/or assemblies containing such EEE parts. This plan is in compliance with:
- SAE AS5553D; Counterfeit Electrical, Electronic and Electromagnetic (EEE) Parts Avoidance, Detection, Mitigation, and Disposition
- SAE ARP6328; Guideline for Development of Counterfeit Electronic Parts: Avoidance, Detection, Mitigation and Disposition Systems
When providing replacement components, Leonardo DRS Nuclear I&C analyzes the original equipment specification requirements, identifies any obsolete sub-components, devises component replacement strategies, and implements engineering hardware solutions to ensure that the replacement components meet or exceed the form, fit and function of the original components.
- Design Change/Update
- Repair/Refurbish
- Reverse Engineering/Retrofits
- Component Verification Plans (Used for Parts from Unauthorized Distribution Channels)
- Component Substitution
Safety Systems
PLµS 32 Digital Control System

The Leonardo DRS Nuclear Instrumentation & Control (Nuclear I&C) PLμS 32 Distributed Control System provides a complete spectrum of functions for Class 1E and non 1E safety systems including loop control, logic, analog and sequential control, data acquisition and management. The PLμS 32 distributed control systems have logged over a million hours of safety critical plant operations above and beyond the 500,000,000 hours logged by prior Nuclear I&C systems.
The highly modular PLμS 32 architecture provides solutions ranging from single plant subsystem control to complete Balance of Plant (BOP) applications. PLμS 32 is based upon a fault-tolerant architecture featuring PERFORM Net that provides redundancy for all data paths and a dedicated microprocessor for each control loop. The system can be configured to be highly distributed with I/O and control functions located in the field, or highly centralized with all I/O and control functions located in one area without degradation in performance.
The PLμS 32 system provides operator interfaces ranging from traditional push buttons, indicators, and auto/manual stations to a state-of-the-art safety related Video Display Unit (VDU) providing a “soft control” user interface to your critical system applications. The VDU provides select and confirm touch screen control for all plant operations.
PLμS 32 delivers demonstrated reliability suited for all critical control systems.
Product Features:
- Deterministic High-Speed Fiber Optic
- Hot Swappable Modules
- Graphical User Interface for Configuration, Modification of Control Loops, and Documentation
- Extensive System Diagnostic Capability
- Designed for a 40+ Year Product Life
- Application Firmware Contained on EPROM supporting cyber security
Features on Each Module:
- Power Auctioneered on Each Module
- Modules are Hot Swappable
- Module divided into three sections
- Control (Operator Interface)
- Logic (Microprocessor and Communications)
- Field (Field Control Devices)
- Hardware Watch-Dog Timer on Every Module
- Each Module Has Control Capability with Input and/or Output Capability
- 4-20 mA In/Out, TC, RTD (All with Auto-Calibration)
Emergency Diesel Generator Controls

The Leonardo DRS Nuclear Instrumentation & Control (Nuclear I&C) Voltage Regulator and Speed Controller were designed from the ground up for Class 1E safety related nuclear applications, specifically for use with emergency diesel generators.
The Digital Voltage Regulator is designed to maintain a constant output voltage from a diesel generator. Through the use of control logic and feedback monitoring, the voltage regulator compensates for changes in the load to ensure a constant voltage output.
Just as the voltage output must be maintained, the speed of the diesel generator must also be managed. The Nuclear I&C Speed Controller is designed to do just that. Through the use of control logic and feedback monitoring, the speed controller compensates for changes in the load to ensure a constant voltage output.
Together with an Emergency Diesel Generator (EDG), the Nuclear I&C Digital Voltage Regulator and Speed Controller enables safe and seamless operation of the power plant in the event of loss of power.
Product Features:
- Microprocessor design
- DSP is used for fast control algorithm processing
- Safety related/class 1E
- Isolation between power and control electronics
- Shielding for EMC requirements
- NEMA-12 enclosure
- Passive cooling to avoid need for fans or ventilation
Video Display Unit

The Leonardo DRS Nuclear Instrumentation & Control (Nuclear I&C) PLμS 32 Video Display Unit (VDU) is a Class 1E safety rated video display system providing a “soft control” user interface to your critical system applications. The VDU provides select and confirm touch screen control for all plant operations. The operator has real-time access to critical operating information through an advanced display management system.
The VDU simplifies safety applications by providing configurable mimic and status screens with touch screen controls. The VDU provides a reliable and user-friendly alternative to traditional discrete controls to operate your Class 1E safety systems and non-safety systems. The VDU is an integral component of the PLμS 32 control system interfacing directly to the fault tolerant PERFORM Net fiber optic network.
In addition to the 20.1 inch video display, the VDU includes a 19 inch rackmount chassis featuring redundant hot swappable power supplies with independent AC inputs and auctioneered DC outputs providing power to the display. Redundant PERFORM Net fiber optic network interface cards are provided to perform monitoring and control functions.
All applications and process screens are developed by Nuclear I&C to meet the strict standards of the U.S. Nuclear Regulatory Commission (NRC) that ensure quality and reliability. Interfaces to non-PLμS 32 systems can be provided as required.
Interfaces to non-PLμS 32 systems can be provided as required.
Product Features:
- V&V’d software
- Touch screen interface
- No keyboard
- No mouse
- PERFORM Net interface
- PLµS 32 system diagnostics
Sensors & Transmitters
Pressure & Differential Pressure Transmitters

The Leonardo DRS Nuclear I&C Pressure Transmitters are qualified for Class 1E safety related nuclear applications. The basic design is a Bellows/LVDT construction; a technology which Leonardo DRS Nuclear I&C has over 60 years experience of deploying reliably in nuclear applications. Leonardo DRS Nuclear I&C manufactures a broad line of transmitters and sensors to monitor pressure, flow, level, temperature, speed and position for severe environment applications.
Our sensors and transmitters are designed and qualified to operate in extremely adverse environmental conditions encountered in both primary and secondary plant applications. Our sensors and transmitters are highly accurate and will operate continuously for decades in critical applications. Longer life corresponds directly to lower overall operating costs through the elimination or reduction of periodic transmitter replacement due to high temperature or radiation degradation over the life of the plant.
Product Highlights:
- Qualified for Class 1E safety related applications
- Custom application-specific models to suit the harshest needs
- Design into Advanced Reactor Applications to yield unmatched performance that can’t be satisfied with currently available transmitters
- Over 50 years of experience producing extremely rugged units for pressure, differential pressure, position, and temperature
Reactor Coolant Pump Speed Sensors / Pre-Amp

The Leonardo DRS Nuclear I&C speed and phase sensors monitor the rotational speed and direction of the reactor coolant pump. They are designed, built, and tested in accordance with U.S. Nuclear Regulatory Commission (NRC) requirements for Class 1E safety-rated equipment under our 10 CFR Part 50 Appendix B nuclear quality assurance program. The all-stainless-steel construction allows the sensors to operate continuously in the most extreme environments.
A self-powered device that generates electrical signals as ferromagnetic elements on the pump’s rotating cylinder pass by, enabling pump speed measurement without the need for an external power source.
Key Product Features:
- The function of the pump speed sensor is to produce an AC signal whose output is linearly proportional to pump rotation speed
- All stainless-steel construction
- Safety related/class 1E
- IEEE 323 and 344
- Preamplifier signal conditioner is also available
- Flexible probe extension length to suit sensor well
Quality
Focused on Continuous Quality Improvement
Leonardo DRS Nuclear I&C has established one comprehensive quality program designed to meet the stringent requirements of our customers and regulatory authorities.
Leonardo DRS Nuclear I&C has been a supplier to the Commercial Nuclear industry for over 55 years. Over this time, we have maintained an NQA program to ensure the quality of products provided to the Commercial Nuclear industry. The initial NQA program was developed in compliance with ANSI N45.2, 1971, “Quality Assurance Program Requirements for Nuclear Power Plants” and has been updated throughout the years to meet the changing quality requirements. With the implementation of Appendix B, “Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants,” to 10 CF Part 50, “Licensing of Production and Utilization Facilities”, Leonardo DRS Naval Power Systems updated its NQA program and has been in compliance with these requirements since that time.
The Leonardo DRS NQA program is also in compliance with the following: NQA-1; ASME NQA-2a, Part 2.7 – Software; and 10 CFR Part 21.
Our Quality program has been audited by the US NRC, the Nuclear utility’s NUPIC audit process as well as our customers.
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