The latest version of the HLA(High Level Architecture) standard developed by the US Department of Defense was established as an open and internal IEEE 1516 HLA standard in 2000. Commercial applications based on the IEEE 1516 have already developed in the non-defense industry. We participated in several development projects for NTS (Nuclear Training Simulator). Extensive modifications are necessary to make a new and/or upgraded NTS because the previously developed simulation softwares have not two desirable property: reusability and interoperability. We reviewed the IEEE 1516 specifications to develop NTS having the capability of reusability and interoperability. Our review activities were forced on application development process, supporting tools, and software structure of NTS. The primary goal of this review is to identify what are constraints or problems to be resolved when we apply IEEE 1516 to NTS development. In this paper we suggest several recommendations for NTS developers.