This is a request for Expressions of Interest from industry to propose tests and experiments using the MARVEL microreactor test bed, which aims to demonstrate novel electricity, heat, and operational applications. The process involves a feasibility assessment intended for Fiscal Year 2026, followed by a physical implementation phase intended for Fiscal Year 2027-2028. The work will be performed at the Idaho National Laboratory. The MARVEL reactor is an 85kWth system designed to produce over 10 kWe of electricity and, in a second stage, provide process heat above 300°C. Promising concepts will be invited to a later stage for a detailed proposal.