Spent nuclear fuels, a by-product of nuclear power generation, contain high levels of heat and radiation, which pose potential risk to the human living environment. They are stored in and managed by either dry or reservoir storage facilities now but 94 % of storage capacity will be filled. The most practical and economically viable solution to mitigate storage scarcity is a high-level nuclear waste (HLW) repository for deep geological disposal at depths ranging from 500 m to 1000 m.

The harsh environmental conditions of HLW repositories make structural health monitoring imperative. To prevent the leakage of radionuclides, however, the disposal tunnel is backfilled after nuclear waste disposal, which restricts human access and makes it impossible to replace or remove monitoring sensors. Therefore, it is essential to analyze the impact of high temperatures and radiation on not only structures, but also piezoelectric sensors and evaluate their suitability through a quantitative lifespan assessment.

In this study, the lifespan of a monitoring sensor was experimentally and statistically derived, and the enhancement of the sensor lifespan after shielding was discussed.