Verification of factors affecting load of metal gasket

Dual purpose casks for transport and long-term storage has a groove-type structure such that a groove is provided on the lid of a cask and a metal gasket is closed in the groove to achieve stable sealing performance. The metal gasket used at the seal boundary of a cask consists of three components: a coil spring, an inner jacket, and an outer jacket. The cask has a structure to tighten up a metal gasket with the lid bolts. Therefore when the lid of the cask cannot be completely closed, the metal gasket becomes unstable. As a result, sealing performance may be lost by impact such as falling of the cask, etc. Therefore, the compressive load of the metal gasket at tightening must be less than the total tightening load. Also, since to achieve the required sealing performance, the compressive load of the metal gasket at tightening must be larger than the compressive load to achieve the sealing performance. The compressive load to achieve the sealing performance depends significantly on the condition of the gasket outer jacket and of the sealing surface of the cask. The influence of the sealing surface condition of the cask has been reported by PATRAM2016 and PATRAM2013. This report verifies factors affecting the compressive load of the metal gasket by the finite element method. First, the compressive load of the metal gasket was sought by the finite element method, and the value was compared with the experimental results. The results of the finite element method corresponded reasonably well with the experimental results, and the analytical approach by the finite element method has been established. Next, the relationship between the diameter of wire used for coil spring and the compressive load of a metal gasket at tightening was verified by using the finite element method. As a result, it was confirmed that the compressive load at tightening increases with the increase of the diameter of wire used for coil spring and the diameter of wire used for coil spring is one of the important factors significantly affecting the compressive load of a metal gasket at tightening.