In light of the exceptional performance of the Reactor Core Isolation Cooling (RCIC) Systems during the 2011 accidents at Fukushima Daiichi Units 2 and 3, a better understanding of the system’s true operating potential and realistic limits has become an area of active interest. The system, which supplies cooling water to the reactor in various scenarios, has at the heart of it a Terry steam turbine which drives a pump. Previously, conservative analyses predicted RCIC System failure where Fukushima demonstrated operability. In addition, systems-level codes have had difficulties adequately modeling the behavior of Terry turbines, especially in cases of two-phase (steam-water) ingestion. An improved understanding of the true behavior of the system and its constituent components is key not only to understanding the progression of the Fukushima accidents but it also promises to offer improved operator guidance and a potential avenue for cost savings.

The Terry Turbine Expanded Operating Band Program was born of the desire for improved knowledge and modeling of Terry turbine-based systems shared by almost all Pressurized Water Reactor and Boiling Water Reactor owners and operators in the world. It is an international collaboration intending to improve the current understanding of Terry turbopump behavior through experiments and simulation, thus expanding its operational range, with goals of improving nuclear reactor operations, enhancing safety and reliability, and reducing costs. To that end, research will be conducted on scales from the level of components inside the turbine up to full-size systems. Experimental testing is underway at Texas A&M University, and modeling work is being performed in both the US and Japan.