Conceptual Design and Thermal-Structural Analysis of the New MIT Research Reactor Internals
Name
foxen-mfoxen-sm-aeroastro-2026-thesis.pdf
Size
14.84 MB
Format
Adobe PDF
Checksum (MD5)
d58c6ffa188dbe5eb8b63bee8e82b853
Author(s)
Foxen, Mary Grace
Advisor(s)
Buongiorno, Jacopo
Date Issued
May 2026
Publisher
Massachusetts Institute of Technology
Abstract
Research reactors play an important role in the development of future aerospace and space nuclear technologies. As interest grows in nuclear thermal propulsion, lunar surface fission power systems, and long-duration deep-space missions [1,2], experimental validation of irradiated material behavior and system performance becomes increasingly important for the development of these technologies. In this context, nuclear engineering is becoming increasingly interconnected with future aerospace applications, with high-performance research reactors providing the neutron irradiation environments, experimental facilities, and testing capabilities necessary to support the development of next-generation space nuclear systems [3]. The Massachusetts Institute of Technology Research Reactor (MITR-II) has served as a major research and educational facility for over five decades, supporting neutron science, isotope production, and materials irradiation [4]. In support of future reactor modernization efforts and the transition toward high-assay low-enriched uranium (HALEU) fuel [5], this thesis presents the conceptual structural design and thermal–structural evaluation of the internals for the proposed new reactor, MITR-III. MITR-III will incorporate a high-density HALEU U-10Mo fuel core operating at an increased thermal power level from 6 to 10 MWth while remaining within the existing containment building. The design introduces expanded inner and outer core tanks, revised core support structures, increased experimental and storage capabilities, and a modular solid MgO reflector that will replace the existing heavy-water reflector configuration. Thermal analyses were performed to evaluate volumetric gamma heating within the MgO reflector and to develop a bypass cooling configuration capable of maintaining peak outer aluminum cladding temperatures below 90◦C under nominal operating conditions using approximately 2.4% of the total primary coolant flow. Analytical calculations and finite element heat transfer simulations demonstrated that dedicated bypass cooling channels substantially reduce reflector temperatures relative to natural convection cooling alone and provide a feasible thermal management strategy for the proposed reflector geometry. Stress analyses of the designed MITR-III core support structures were performed in Abaqus under representative thermal and mechanical loading conditions, including gravitational loading, hydrostatic pressure, hydraulic lifting forces, and thermally induced stresses. The evaluated structures, including the grid plates, vertical support, inner and outer core tanks, and support skirt, were shown to remain well below the ASME allowable stress criteria under the considered steady-state operating conditions. Collectively, the results of this work demonstrate the preliminary thermal and structural feasibility of the proposed MITR-III reactor concept and provide a foundation for continued design development and future integrated neutronic, thermal–hydraulic, and structural analyses.
MIT Department
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
Terms of Use
In Copyright - Educational Use Permitted
Copyright retained by author(s)
Persistent DSpace Link
