Performance of Permanent Magnet Flow-through-Type Sodium Flowmeters in EBR-II Instrumented Subassemblies

The first two instrumented fueled subassemblies in EBR-II included permanent-magnet sodium flowmeters. The first operated for the duration of the test, four months, with no observable degradation. Its signal was about six percent below that calculated. The second flowmeter had been precalibrated in a sodium system. Operating data from EBR-II indicates that its sensitivity has been stable within three percent during the first 150 days in the core. Post-test examination will supply more conclusive data.