Woodruff School of Mechanical Engineering

NRE/MP Seminar

Nuclear & Radiological Engineering and Medical Physics Programs


How Neutrons and Synchrotron X-rays Can Be Used to Understand Microstructural and Mechanical Properties in As-Fabricated Nuclear Fuel Plates


Dr. Maria Okuniewski


Idaho National Laboratory


Tuesday, April 23, 2013 at 11:00:00 AM


Boggs Building, Room 3-47


Dr. Chaitanya Deo


Currently in the U.S., there is an ongoing effort to replace highly-enriched uranium (HEU) fuels with low-enriched uranium (LEU) fuels in research and test reactors in support of both non-proliferation and the minimization of HEU. The fuel that may be utilized for the conversion of some of the high performance research reactors is U-10wt.%Mo (U10Mo) alloy foil encased within an Al-6061 cladding. These fuel plates are fabricated by rolling processes and hot isostatic pressing (HIP’ing). During the fabrication process, residual stresses are introduced into the plates during the rolling of the U10Mo fuel foils, as well as during the HIP’ing process via the difference in thermal expansion coefficients in the U10Mo and Al. Moreover, various aspects of the microstructure evolve due to the thermal and mechanical processing of the plates. Synchrotron x-ray diffraction was utilized to measure the spatially resolved residual strains and stresses, phase fractions of the fuel plate constituents, relative dislocation densities, and crystallite sizes in a variety of fuel plates. Neutron diffraction was used to examine the in-situ strain evolution of a fuel plate during heating and in-situ tensile tests were performed to determine the elastic modulus of U10Mo. Selected results are compared to finite element calculations.


Dr. Maria Okuniewski works at Idaho National Laboratory.