Measurement system and data analysis methods to evaluate Flow Induced Vibration in a nuclear fuel pin bundle with heavy liquid metal flow

This work describes the measuring system and analysis methods designed and developed to investigate the Flow Induced Vibrations (FIV) in a nuclear fuel pin bundle test section with flowing lead. The measuring system was conceived to monitor pins displacement in terms of amplitudes and frequencies. Applied methods are devoted to calculating the displacement using a raw signal coming from strain gauges (SGs) adequately installed into the test section, and to evaluate the uncertainty characterizing the measuring chain.