Seattle-based Ultra Safe Nuclear (USNC), developer of a high-temperature, gas-cooled microreactor design that has drawn interest from potential customers and research and development funding from the Department of Energy, announced yesterday that it has filed a petition for Chapter 11 bankruptcy to facilitate its sale to Standard Nuclear Inc. The filing, made in the U.S. Bankruptcy Court in Wilmington, Del., includes USNC and its subsidiaries, Ultra Safe Nuclear-Technologies, USNC-Power, and Global First Power.