CALDON LEFM Ultrasonic MKIII Nuclear Flow Meter

Overview

Designed specifically for feedwater applications to allow nuclear power plants to license for a Measurement Uncertainty Recapture (MUR) uprate of up to 1.7%, the CALDON LEFM MKIII Ultrasonic chordal meter body design has been in service since 2010.

The meter’s chordal transducer path configurations are based on the Westinghouse development of the Gaussian integration technique delivering optimum measurement performance. The MKIII design standard configuration consists of an eight-path, dual plane CheckPlus meter allowing plants to unlock their full potential under the NRC’s Appendix K power uprate program. The perpendicular arrangement of the planes corrects for swirl and maintains accuracy through hydraulic profile changes, allowing for installation in almost any feedwater piping configuration.

The third-generation design marked a transition from reliance on externally welded transducer housings to a forged and machined meter body with threaded housings, providing improved tolerance control over its predecessors while additionally mitigating the potential of a weld failure at the wetted boundary. The change to internal housing manifolds results in less variability in path alignment, improving receive signal quality, while reducing maintenance clearance requirements providing improved access. Alongside the update to the LEFM meter body design came an upgrade to the LEFM nuclear application transducers. The MKIII transducers were designed with a larger form factor that allows for a larger piezo crystal, and eliminates pushrods as compared to the MKI & MKII designs. These design improvements produce higher Coherent Signal-to-Noise (SNRc) ratios at lower gain values in addition to increased longevity.