Development of I2S-LWR instrumentation systems

•Integral Inherently Safe Light Water Reactor instrumentation is discussed.•Ultrasonic primary flow monitoring for integral reactors is proposed.•In-vessel instrument cable strategies are discussed and paths proposed. The Integral Inherently Safe Light Water Reactor (I2S-LWR) is a novel pressurized water reactor (PWR) concept being developed by a multi-institutional team led by Georgia Institute of Technology, under the Department of Energy’s Nuclear Energy University Programs Integrated Research Projects (DOE NEUP IRP). The I2S-LWR aims to deliver approximately 1GWe power output, comparable to other large scale LWRs, while simultaneously delivering improved safety over other Generation III+ LWRs. This reactor concept aims to achieve these goals by incorporating inherent safety features in the design. These features include an integral design of the primary coolant and control rod drive systems which eliminate the possibility of large break loss of coolant and control rod ejection accidents. It also features a fully passive decay heat removal system (DHRS) designed to providing indefinite core cooling as long as the core remains submerged in coolant. These features impact the design of the instrumentation system in a variety of ways. The University of Tennessee is developing instrumentation and control design concepts for the I2S-LWR. The development of instrumentation systems in the I2S-LWR, and the challenges and technology gaps to be addressed, are presented.