NUMAC Monitors

The NUMAC (Nuclear Measurement Analysis and Control) monitors are a best-in-class family of monitoring instruments designed to improve plant performance and increase plant longevity. NUMAC has a common, modular chassis design providing digital solutions and resulting in a clear data picture for plant operators.  The monitors are designed for specific functional applications with embedded firmware, protecting against cybersecurity threats.

NUMAC monitors include:

• RAD monitors
• PRNM
• WRNM
• ATIP

Radiation (RAD) Monitors

Detection of gamma radiation at low levels in process equipment and building areas.

• Gather information from several sensor types and initiate control function to other peripheral systems
• Provide direct input to safety systems, as well as local alarms for human safety
• Single unit chassis with up to 8 sensor inputs
• More than 6,380 combined operating years

Benefits

• Proven NUMAC electronics and simplified chassis installation
• Automated and continuous self check
• Simplified calibration via menu-driven directions              
• Standard NUMAC help menus, parameters, and status screens
• Redundant internal power supplies
• Common spares with other NUMAC systems
• Data transfer to the plant process computer        
• Digital filtering
• Modular components

Power Range Neutron Monitor (PRNM)

Neutron monitor and trip logic at operational power levels

• Monitors reactor power from 20% to 125% during normal operation
• Connects to fixed in-core Local Power Range Monitoring (LPRM) sensors
• Provides reactor trip signals to the plant safety systems
• More than 4,500 combined operating years 

Benefits

• 4-channel trip voting logic reduces spurious SCRAM occurrences by 50 percent
• Enables core stability monitor options
• Proven NUMAC electronics and simplified chassis installation
• Automated and continuous self check
• Simplified calibration via menu driven directions               
• Standard NUMAC help menus, parameters, and status screens
• Redundant power supplies
• Common spares with other NUMAC systems
• Data transfer to the plant process computer        
• Digital filtering
• Modular components

Wide Range Neutron Monitor (WRNM)

Neutron monitor and trip logic at startup power levels

• Monitors reactor power from 0% to 20%
• Designed to replace the entire SRM and IRM System
• 8 fixed, in-core sensors versus 12 retractable sensors for SRM/IRM
• More than 1,800 combined operating years of experience
• 27 WRNM installations since 1989

Benefits

• Auto-range switching and rate-based logic removes spurious trips
• Reduced maintenance and dose
• Proven NUMAC electronics and simplified chassis installation
• Automated and continuous self check
• Simplified calibration via menu-driven directions
• Standard NUMAC help menus, parameters, and status screens
• Redundant power supplies
• Common spares with other NUMAC systems
• Data transfer to the plant process computer
• Digital filtering
• Modular components

Automatic Traversing In-Core Probe (ATIP)

Calibration measurement for the in-core power sensors

• Calibrates Local Power Range Monitor Sensors (LPRM)
• This system controls a drive mechanism and indexer that runs a sensor next to each LPRM
• Readings are compared to values provided by the PRNM System
• Over 900 combined operating years
• 17 installations since 1986

Benefits

• Automatic sequencing of all channels simultaneously
• Digital torque data available
• Proven NUMAC electronics and simplified chassis installation
• Automated and continuous self check
• Simplified calibration via menu-driven directions
• Standard NUMAC help menus, parameters, and status screens
• Redundant internal power supplies
• Common spares with other NUMAC systems
• Data transfer to the plant process computer
• Digital filtering
• Modular components