Abstract
On-line structural health corrosion monitoring in advanced molten salt reactor heat exchangers is desirable for detecting tube degradation prior to leaks that either would cause mixing of heat exchanger fluids or release of radiologically contaminated fluids beyond the design containment boundary. This program seeks to demonstrate feasibility for a torsional wave mode sensor to attach to the outside of a long (30-m) heat exchanger tube in the stagnant flow area where the tube joins the heat exchanger plenum and where it is possible to protect a sensor cable from high-force flow connecting through a heat exchanger shell to a monitoring instrument. The envisioned sensor and cable management approach will be impractical to implement on existing heat exchangers; rather sensors must be installed in conjunction with the heat exchanger fabrication. Initially, flaw surrogates of interest (50% notch and 50% flat bottom hole) have been detected in a 3-m tube using low-temperature PZT piezoelectric crystals. The transducer consisted of multiple shear elements placed circumferentially around a tube. The program will continue to investigate higher temperature piezoelectric ceramics, long-term performance of high temperature adhesives, and flaw sensitivity on long (30-m +) tubes.
On-Line Monitoring and Diagnostics of the Integrity of Nuclear Plant Steam Generators and Heat Exchangers, Volumes 1, 2