Japan began constructing and upgrading HRS (Hydrogen Refueling Stations) for its FCV (Fuel Cell Vehicle) demonstration program in 2002, as shown in Fig. 1. In 2013, Japanese energy providers started constructing commercial HRS for refueling FCV with 70 MPa hydrogen, and almost 100 HRS are now in service. Maintaining the reliability of refueling equipment is essential for safe, stable operation of commercial HRS. However, as a result of experience with commercial HRS operation during the past few years, Japanese energy providers have recognized that maintenance for small leaks from cone and thread mechanical joints involves a significant loss of resources.
