To provide a safer and cost effective solution, a new concept of storing liquefied natural gas (LNG) in a lined rock cavern with containment system has been developed. It consists of protecting the host rock against the extremely low temperature and providing a liquid and gas tight liner. Moreover, moderated and controlled frost development in the surrounded rock mass contributes to create an ice ring, which acts as a secondary barrier against any possible leakage. To demonstrate the feasibility of this concept and validate numerical modeling and calculations, a pilot plant was constructed in the Daejeon Science Complex in 2003. A pilot test using liquid nitrogen was conducted from January through August, 2004. In this paper, measured in-situ rock mass response from the pilot test are presented and analyzed. Overall, the results confirm that both construction and operation of underground LNG storage in lined rock caverns are technically feasible from a rock mechanical point of view. The Daejeon LNG storage pilot cavern represents an important step in the validation of the technology of lined cavern storage of LNG. Even though the cavern was small, this project has provided information suitable for assessing the potential of this new technology, and for identifying critical points for its construction, start up and operation.
Many attempts have been made to store LNG (Boiling Temperature: -162?) in unlined rock caverns but were not successful. If the storage is unlined and frozen down to -162?, the rock is cooled and the rock joints start to reopen, a part of the gas flows into the joints and continues cooling inside the rock wall. This opens the joints successively and heavily increases the cooled area and the extent of the cooling front.