Passive heat removal impact on AREVA HTR design

The AREVA modular HTR steam supply system (SC-HTGR) is being developed to provide high temperature steam for a variety of applications such as chemical processing, refineries, tar sands, and synthetic fuel production. The passive safety characteristics of modular HTRs are important for such applications, since siting must consider the collocation of the HTR and the industrial energy user. Maintaining these characteristics is an important consideration during the design optimization process. Particular attention must be given to passive decay heat removal, since this capability is a strong function of the system geometry and operating conditions. The most challenging heat removal scenario is a depressurized loss of forced circulation i.e. a depressurized conduction cooldown (DCC). Therefore, DCC is a key consideration in determining acceptability of initial design and in guiding future design activities as the concept is optimized. Initial scoping DCC analyses are performed to confirm basic acceptability of the current SC-HTGR design. Both fuel temperatures and key component temperatures are evaluated. These initial results confirm the safety characteristics of the AREVA HTR concept, and they provide a sound basis for further optimization of the design.