Many nuclear power plants are operating below their licensed power rating because of inaccurate feed water flow measurements.  Installing an LEFM CheckPlus system allows utilities to correct their calorimetric calculations for the extent of venturi fouling.  In addition to providing megawatt recovery, the precision of the LEFM CheckPlus for feed water flow measurement also allows nuclear power plants to operate closer to their rated power, without compromising safety margins.  The LEFM CheckPlus is ideally suited for digital feed water control applications.  A two year evaluation program by Japanese utilities has verified the suitability of these systems in advanced BWRs (Boiler Water Reactors).

The LEFM CheckPlus is comprised of a spool piece and electronic unit.  The electronics used with the LEFM CheckPlus Systems are rack mounted within a freestanding cabinet. One to four spool pieces can be connected to a single LEFM electronics unit. An acoustic-processing unit controls the timing of electronic pulses to the transducers in the spool pieces. A central processing unit calculates volume flow, mass flow and temperature. A simple, but powerful touch screen interface displays all data. Measured values and system parameters can be displayed graphically to provide operators with both current and historical information about feed water flow. The electronics are designed to provide on-line verification of performance. Continuous self-checking circuitry ensures accuracy and reliability. LEFM software also provides automatic diagnostics for predictive maintenance.

The eight paths of the LEFM CheckPlus are arranged in two crossing planes of four paths each. This cross plane arrangement reduces measurement uncertainty due to hydraulics.

The LEFM CheckPlus measures feed water mass flow rate to within ±0.3%, and feed water temperature to within 0.5 degree F. LEFM System accuracy specifications take into account all parameters that can have any potential effects on performance.

The eight paths of the LEFM CheckPlus provide an important additional benefit. The LEFM CheckPlus offers total redundancy, both sensors and electronics. This total system redundancy assures that a measurement signal is available 100% of the time from the LEFM CheckPlus System, and that the same high degree of performance is always maintained. 

LEFM CheckPlus Chordal System features

• Guaranteed highly accurate flow measurement
• Accuracy specifications which include effects of all parameters that could impact performance
• Verifiable performance on-line via continuous self-checking circuitry
• Easy to use, intuitive, touchscreen offering graphical displays of real time data and historical trending
• Continuous, preventative diagnostic software
• Independent system testing and verification at Alden Laboratories in plant specific hydraulic piping model
• Total redundancy (sensors and electronics)
• Eight-path spool piece for installation in tight piping close to elbows, tees, etc., with no hydraulic effects on performance
• All welded spool piece design
• Simple transducer replacement that does not interrupt flow

Questions or comments?  Contact us!