From Ars Technica: AMD and Cray have announced that they're building "Frontier," a new supercomputer for the Department of Energy at Oak Ridge National Laboratory. The goal is to deliver a system that can perform 1.5 exaflops: 1.5×1018 floating point operations per second.
The current (Nov 2018) Top 500 leader, Summit at ORNL, runs at 0.2 exaflops.