Modifications to MiniFuel Vehicle Needed to Enable Higher Temperature UO₂ Irradiation Capabilities (Summarizing Issue Report)

Abstract

The Advanced Fuels Campaign (AFC) within the US Department of Energy Office of Nuclear Energy (DOE-NE) supported the conception and initial demonstration of the miniature fuel (MiniFuel) irradiation capability in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. These MiniFuel experiments are a key component of a larger effort to accelerate the qualification of novel fuel concepts and to reduce uncertainty in fuel performance models. MiniFuel experiments to date have been conducted in HFIR's outer vertical experimental facility (VXF) positions. However, there is motivation to achieve irradiation temperatures and fuel burnup accumulation rates greater than what is achievable in the VXF positions to explore high-temperature phenomena and further accelerate fuel qualification. Therefore, MiniFuel irradiation experiments are being considered in HFIR's removable beryllium region, which is closer to the fueled core than the VXF region. This report summarizes the design modifications to the MiniFuel irradiation vehicle needed to enable high-temperature (i.e., >1,000°C) irradiation tests with rapid burnup accumulation. Modifications to MiniFuel Vehicle to Enable Higher Temperature UO2 Irradiation Capabilities

Design and Assembly of MiniFuel Targets for Characterization of High Burnup UO₂ Specimens Irradiated in the High Flux Isotope Reactor

“…Each MiniFuel target is loaded into either the VXF or RB MiniFuel basket at its designated radial and axial (RA) position. The neutronic and thermal design process for MiniFuel targets is described in Petrie et al, [6] and Gorton et al, [7] and is briefly reiterated here. Neutronics calculations are performed using HFIRCON [8], a wrapper code that couples the Monte Carlo N-Particle (MCNP) code [9] with the Oak Ridge Isotope Generator (ORIGEN) [10] module of the SCALE package.…”