I. Introduction Battelle Energy Alliance, LLC (BEA), Management & Operating Contractor of the U.S. Department of Energy (DOE) owned Idaho National Laboratory (INL). BEA is collaborating with the Natio... I. Introduction Battelle Energy Alliance, LLC (BEA), Management & Operating Contractor of the U.S. Department of Energy (DOE) owned Idaho National Laboratory (INL). BEA is collaborating with the National Aeronautics and Space Administration (NASA) to develop the SR-1 Freedom interplanetary spacecraft. BEA is seeking an Expression of Interest (EOI) from prospective offerors to support design/build of the SR-1 Freedom Reactor Radiation Shielding system (RRS). II. PROCESS BEA is seeking qualified firms to compete for the design/build contract in support of the BEA/NASA SR-1 Freedom RRS system. As determined by BEA, responders to this EOI may receive a Request for Proposal (RFP) that will require detailed technical and price proposals be provided for evaluation and ranking under a source selection process. Interested firms are advised that RFP release is anticipated late September/early October 2026 and the source selection/award decision is anticipated in October 2026. The contract award type will be firm-fixed price. The design/build contract will be awarded in progressive phases as the firms demonstrate the ability and competency to successfully plan, design, and fabricate the RRS. BEA may initially award multiple Design/Build contracts to various firms though the Design phase to make a final determination of which firm will continue with the fabrication. Completion of this project must be no later than July 2027. III. PROJECT DESCRIPTION The RRS will be designed and fabricated for the SR-1 Nuclear Power Module (NPM) SR-1 Freedom which will be built at the Materials and Fuels Complex (MFC) at the INL. MFC is located approximately 33 miles west of Idaho Falls, Idaho. The RRS system will provide radiation shielding for various components of the spacecraft from the nuclear reactor neutron and gamma photon radiation. The composite weight of the RRS will need to be less than 1200 kg and interface with face four separate NPM systems: The reactor structure Control drum actuators The Heat Management System (HMS) heat pipes Power Conversion System (PCS) structure The RRS system and materials will need to operate in the vacuum of space at temperatures ranging from space ambient temperature of -273°C to 800 °C when in proximity to the reactor and HMS heat pipes. The RRS system and materials will need to be designed, tested, and qualified to withstand the launch forces and vibrations associated with launch into space as well as the operation environment described above. The RRS must provide adequate radiation shielding for various SR-1 Freedom systems, structures, and components, and prescribed gamma photon total ionizing dose limits and fast neutron fluences limits. The RRS is positioned between the reactor and the PCS. The HMS transfers heat from the reactor via several dozen heat pipes to the PCS to convert the heat energy into electrical energy. In addition to the penetrations for the HMS heat pipes, the RRS must accommodate penetrations for the rods of the control drum actuators, located on the PCS side, which pass through the RRS and into the reactor. Specific dimensions, configurations, reactor characteristics, dose limits, etc., may be considered export controlled information and will not be provided in this expression of interest. A general layout of the RRS and interfacing systems is provided below. IV. Submittal Interested firms are requested to provide expressions of interest to the undersigned by close-of business on September 24, 2026. Included must be sufficient written information confirming the responder’s qualifications addressing each of the following criteria: Experience in radiation shielding material design and fabrication. Radiation transport modeling or equivalent shielding analysis. Capability to meet the design/build schedule. Capability to provide and fabricate the shielding components in the needed geometries. Proper identification and execution plan for material testing & qualification. Agreement to have a documented quality program that is consistent with the guidelines of ISO 9001-2015 and ANSI/ASQC C1-1996 General Requirements for a Quality Program. Be capable of meeting QA audit requirements to be added to the INL QSL. Note that responses must be no more than 20 pages in length. Only potentially qualified offerors, as determined by BEA, will receive the RFP for the project. If you have questions, need additional information, or need to speak with a BEA Point of Contact, please contact Chase Egbert via email at chase.egbert@inl.gov . Technical questions must be submitted in writing via email.