In-Rod Sensor System Irradiation Test Results with Segmented Fuel Assembly

Westinghouse is developing an In-Rod Sensor System (IRSS) [1, 2] capable of measuring key fuel rod operational parameters such as center-line fuel temperature, rod internal pressure, and axial fuel pellet stack elongation, all without the need of a penetration to the sealed fuel rod boundary. The sensor operates by utilizing a low frequency magnetic field to transmit data through numerous layers of metal barriers. When parameters are measured in real-time and combined with fuel performance model and atomistic modelling results, the time required to qualify new fuel technologies is greatly reduced, supporting Accelerated Fuel Qualification (AFQ) efforts. Furthermore, when applied to a commercial power reactor, operators may use the information gathered by the sensor to reduce safety margin uncertainty and operate closer to plant technical specification limits - thereby increasing economic benefits. The sensor system is under active development for Light Water Reactor (L WR) based fuel assemblies but can also be applied to Gen IV reactor fuel designs with minimal modifications. This paper will focus on recent test results from the Penn State Breazeale Reactor (PSBR). The test campaign demonstrates full system performance in a mock-up fuel rod bundle assembly adjacent to the PSBR core. The testing at PSBR is the latest in a campaign of prototype tests, including those conducted at the Massachusetts Institute of Technology Reactor (MlTR) and Oak Ridge National Laboratory's High Flux Isotope Reactor (ORNL HFIR). The results from those tests were covered in the previous NPIC-HMIT conference [3].