TEG-5-Series Nuclear Turbine Controls Now PMG Self-Powered

A Fukushima Event Mitigation Upgrade for Nuclear Safety-Related Emergency Cooling Pump Drive Turbines


Applications

 

PWR Auxiliary Feedwater Pump Turbines (AFPT)

BWR Reactor Core Injection Cooling (RCIC), High Pressure Coolant Injection (HPCI), Low Pressure Coolant Injection (LPCI).

And other turbines in remote applications requiring self-powered operation.

 


 

Description

Conventional Safety Related Turbine (SRT) controls are powered by plant AC primaries and battery-bank fed inverter backup.  The recent events at the Fukushima power plant in Japan has evidenced that extended Station Black Out (SBO) conditions for days are possible from overwhelming natural disasters.  As an effective and valuable addition to the Nuclear Regulatory Commission's (NRC) required DEFENSE IN DEPTH mitigation actions LCC offers the TEG5-Series with fully self-powered PMG to 10 CFR 50 Appendix B design and construction and meeting plant environmental qualifications with extended seismic tolerance to extreme standards.

Unlike some probe-powered commercial governors offered by others, these systems have Permanent Magnet Generators and Power Conditioners which satisfy power demands for not only the digital governors but also the governor valve electric actuator, servo drive, remote operator stations, remote flow controllers and remote flow transmitters.  The PMG in this manner self powers all operational speed control devices.  If steam is available to the SRT, the SRT can be controlled in all modes independent of station power bus losses and standby diesel generator status.

New Technology PMG

The patent-pending new technology PMG provides constant voltage multiphase AC output over a speed range of 500 to 5000 RPM.  Using Niobium Boron rare earth magnets in a compact, brushless,  bearingless and thus extremely low maintenance design, the PMG easily handles the rapid start power requirements while not generating excess power and heat at upper turbine speed ranges.  An additional advanced feature utilizes active capacitance power conditioning which eliminates the need for large electrolytic capacitors and enables radiation hardening of the system in excess of 10 5 Rads cumulative.  The result is a robust nuclear service designed system far superior to presently available commercial re-qualifications.

 

Installation and Commissioning

Since the modification work is confined to the immediate turbine area, and no new plant wiring runs or containment penetrations are needed the installation can be performed in one week with careful planning.  The existing turbine shaft-driven hydraulic pump is removed which provides oil for the hydraulic cylinder positioning the governor valve.  In its place the new PMG rotor is coupled to the turbine end shaft and the PMG stator is bolted to the pedestal base.  The entire PMG resides within the front pedestal cover and is entirely protected from external damage.

The Power Conditioner, Digital Governor, and Servo Drive complete the electronics.  All are radiation hardened designs and are mounted in thermoelectrically cooled enclosure at the turbine front console.  A pair of PMG field coils provide redundant speed feedback signals, eliminating speed probe need and related maintenance.  Since all cable runs are short and local installation cost is modest in comparison with other SR modifications.

Operation

To a great extent operation of the new system is the same as the original controls but now adding dependability and repeatability to system characteristics.  For plants having installed steam bypass systems these may be retained, but block valve opening and full throttle starts are easily controlled due to the much quicker response of the all-electric (no hydraulic) system.  On a typical SRT start the PMG is at full power function at 500 RPM and the Digital Governor is positioning the Electric Actuator in one additional second to arrest the turbine acceleration and proceed with a ramped rate to pumping speeds.  Single or multiple remote operator control stations are available for equivalence with previous system operation.

For More Information

Specific turbine retrofit proposals are available to nuclear generation plants and assigned third-party application engineering firms.  Contact LCC for details.

 

 

TEG-5 Nuclear Feed Pump Turbine Governors

Lovejoy Controls Corporation's TEG-5 line of Nuclear Feed Pump turbine Governors is a commercial version based upon the NavGov 900 Naval Turbine Governor under production for military application. Applications include:

    TERRY TURBINE obsolete Woodward Governors which are no longer supported by replacement spares:

            Auxiliary (or Emergency) Feedwater Pump Turbines (AFW) in Pressurized Water Reactor Plants (PWR)

            Reactor Core Isolation Coolant  (RCIC) Pump Turbines in Boiling Water Reactor Plants (BWR).

            High Pressure Coolant  Injection (HPCI) Pump Turbines in Boiling Water Reactor Plants (BWR)

            Low Pressure Coolant  Injection (LPCI) Pump Turbines in Boiling Water Reactor Plants (BWR)

    The original Woodward Governor designs above represent one of the cruelest jokes ever perpetrated on the US Nuclear industry.  Consisting of a dry-start, self contained oil pump system, these designs are required to quickly pressurize oil and purge air during cold start turbine acceleration.  Without constant diligence and frequent skilled maintenance efforts the pressure to the governor valve hydraulic actuators cannot be established in time and the turbine suffers an over speed trip.  Since these systems are normally in standby service the startup problems are a severe nuisance. 

 

 

 

 

 

 

 

    The electronic components added for some systems (termed "EG-M" and "EG-R") are no better.  All analog 1970's designs containing commercial electrolytic capacitors, these designs have low radiation tolerances (pre-TMI "hand waving" qualifications), tedious calibrations, and as of recently no new spare parts available.  An after-market licensee is performing refurbishing of the old components then recycling shipments between plants.  It is unknown how long this will maintain the installed systems in operable condition. 

 

 

 

 

 

 

 

 

 

 

    SOLUTION for Terry Turbine Control:    The LCC TEG-5

    The TEG-5 (and specific TEG-5A for Aux FW) provide a Safety-Related design replacement package which installs on the turbine pedestals, driving a roller screw electric actuator which positions the governor steam admission valve.  All obsolete Woodward Governor components are removed, and may be sold to remaining die-hard users for a fairly good price.  The TEG-5 operates on a low current 5 Ampere draw of 125 VDC Vital Bus power, and since located at the turbine does not require new pump room penetrations nor power feeds through existing penetrations as competitive designs demand.

Hardware Features:

    ○    Self-Contained Environmentally Controlled Electronics Enclosure holds Governor, Servo Drive, and Local Operator Panel

    ○    Two Remote Control Operator Stations (Remote Pump Control Panel and Control Room Locations)

    ○    Redundant Speed Probes

    ○    EMI/RFI Qualifications

    ○    Radiation EQ Qualifications

    ○    Severe Temperature, Humidity, Shock, and Vibration Qualifications

    ○    Electric Valve Actuator... No dependence on hydraulics.

Advanced Control Features:

    ○    Automatic Startup on Block Valve Opening

    ○    Controlled, Predictable Accelerations

    ○    Self-Monitoring Diagnostics and Alarms with Plant Computer Interface

Advanced Control Advantages:

    ○    Deletes Necessity of Water-Hammer Inducing Steam Bypass System

    ○    Removes Systems from Periodic "On-the-Clock" Repair Pressures


TEG-5A Evaluation Software Simulator, Aux FW        FREE to Qualified Users*

    The TEG-5A Evaluation Software Simulator (ESS) is a Windows-based executive program which may be loaded in any Windows Operating System PC.  The ESS demonstrates by interactive graphics the features and functions of the TEG-5A Governor System in a typical Auxiliary Feedwater Pump Turbine control application.  The ESS was originally designed as a self-paced training tool for operators to familiarize themselves with system functions, but serves equally well for plant evaluations.

    Simulations include:

    1.    Local Control Panel Pushbuttons and Indicators

    2.    Inter-active Turbine Speed Control

    3.    Alarm System

    4.    Automated Startup Ramp System

    5.    Remote Operation from two (2) Remote Operator Control Stations

*    The TEG-5A ESS is available at no charge with on-site restricted software license to personnel at operating nuclear plants.  Distribution of the program to third parties is prohibited.  Contact LCC for details.


TEG-5 Full Hardware Simulator

    A limited number of full hardware TEG-5 mockup systems are available for rental or purchase.  These systems provide a platform for plant evaluation using the actual system hardware.  In order to enable a meaningful system exercise and performance evaluation, special test hardware is included to close control loops for realistic operation.  Each hardware simulator provides:

1.    TEG-5 Turbine Governor with Servo Drive

2.    Roller Screw Electric Actuator

3.   Test Stand Bracket Holding Electric Actuator, Pneumatic Loading Cylinder, Loading I-to-P, and Stroke Transducer.

4.    Turbine Speed Feedback Simulator (TSFS) and Actuator Loading System (ALS) Interface Cabinet.

5.    Support Laptop PC with Software to Run TSFS/ALS.

    The hardware simulator permits simulated operation under a wide range of initial conditions of available steam pressure and pump header pressure.


 

 

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