Development of smart material-based structural integrity monitoring sensors for spent fuel dry storage canisters

This study has been performed focused on developing smart paint-based structural integrity monitoring sensors for detecting the fracture sign prior to CISCC in dry storage canisters. Here, we develop a structure integrity monitoring sensor made of at least 3 kinds of smart paints having differently controlled fracture strains and electrical resistances at fracture. When a dry storage canister is deformed, the smart paints painted on the dry storage canister (especially, its outermost surface) are sequentially fractured according to their fracture strains. A change in the electrical resistance of the structure integrity monitoring sensor induced by each smart paint's fracture is used to detect the fracture sign of a dry storage canister prior to CISCC generation therein. The fracture order of the unit sensing elements is consistent with the fracture strain order of the smart paints. Compared to usual crack propagation sensors, smart paint-based SIM sensor has a noticeable difference. All sensing elements in the usual crack propagation sensors are made of the same material having identical fracture strain, whereas the sensing elements in this sensor are made of smart paints having differently controlled fracture strains and electrical resistances at fracture. The distinct specimen fracture behaviors were also well matched with corresponding sensor breakage signals. Structural integrity monitoring of dry storage canisters by the smart paint-based sensors would contribute to improve the safe operation of dry storage canisters and give an on-time preparation for the licensing of dry storage system and international-level protocol preparation for dry storage canisters. The mechanoelectrical properties of smart material sensors at high temperature and irradiation environmental conditions are planed as a future study.