The high-level waste disposal system is an underground structure exposed to complex environmental conditions such as high temperature, radiation, and groundwater. The high-level waste disposal causes structural cracks and deterioration over time. However, since the high-level waste disposal system is a structure that should be operated for a very long time, developing a high-durability monitoring sensor to detect cracks and deterioration is essential. The durability of the sensor can be evaluated by predicting the expected life through the accelerated life test, one of the reliability qualification tests. The most important factor in the accelerated life test design is setting the harsh stress level. This study figured out the harsh stress level of the piezoelectric sensor, which is commonly used for underground structure monitoring. It is possible to determine the appropriate stress level for the accelerated life test by investigating the harsh stress level for the temperature factor. It will contribute to more accurate life expectancy prediction.

• Hyun-Joong Hwang(Korea Advanced Institute of Science and Technology (KAIST))
• Changhee Park(Korea Advanced Institute of Science and Technology (KAIST))
• Gye-Chun Cho(Korea Advanced Institute of Science and Technology (KAIST)) Corresponding author
• Chang-Ho Hong(Korea Atomic Energy Research Institute (KAERI))