Evaluation of Recent Data From the Sandia National Laboratories Closed Brayton Cycle Testing

At Sandia National Laboratories (SNL), The Nuclear Energy Systems Laboratory / Brayton Lab has been established to research and develop subsystems and demonstrate the viability of the closed Brayton cycles (CBC), and in particular, the recompression CBC. The ultimate objective of this program is to have a commercial-ready system available for small modular reactors. For this objective, R&D efforts must demonstrate that, among other things, component and the system behavior is understood and control is manageable, and system performance is predictable. Research activities that address these needs include investigating system responses to various anticipated perturbations, and demonstrating that component and system performance is understood. To these ends, this paper presents system response to a perturbation, and turbomachinery performance results during steady state operation. A long duration test, with an extensive period at steady state, was completed in the simple CBC configuration. During this period, a cooling perturbation was initiated. Data from this test are presented and evaluated to explain the sequence of events following the perturbation. It was found that a cascading series of events ensued, starting with the fluid condensing effect of the cooling perturbation. The explanation of events emphasizes the highly interactive and nonlinear nature of CBC’s. The comparisons of measured and predicted turbomachinery performance yielded excellent results and give confidence that the predictive methods originally envisioned for this system work well.