Modular modeling system code development and nuclear applications

The development of MMS (modular modeling system) by EPRI is reported. The purpose was to supplement existing transient-analysis codes like RETRAN and RELAP by providing an efficient, economical, user-friendly code to be used by utility engineers for long-term and scoping safety analysis of both fossil and nuclear power plants. As a result of extensive validation and trial user-group experience, it is claimed that MMS has met these objectives. It is concluded that with extensive documentation in place, and a well organized and supported user group, MMS can be expected to be used for a wide variety of utility analyses.