Detection of defects in titanium condenser tubes in nuclear power plants based on high-resolution TMR array probes

Titanium condenser tubes are used in nuclear power plants to condense steam into water, which is then transported back to the reactor for reheating. If condenser tubes are faulty, it may lead to a reduction in condensation efficiency or even cause a safety hazard. The health of condenser tubes in nuclear power plants is related to the safe operation of nuclear power plants. In this paper, a high-resolution tunnel magnetoresistive (TMR) array probe for condenser tube defect detection is investigated. The probe contains 48 TMR sensors uniformly arranged along the circumferential direction, which are encapsulated by gold wire bonding technology with high spatial resolution and high detection sensitivity. The sensor signals are transmitted to the eddy current instrument to achieve detection imaging after timesharing through three multiplexed selector circuits. In this paper, an experimental system was built to test the performance of the probe for detecting defects in titanium condenser tubes in nuclear power plants. The experimental results show that the probe can output high-resolution magnetic field images, and the defect signals can be observed intuitively from the images.