Abstract
Design and safety analyses are underway to convert the High Flux
Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL)
from a high-enriched uranium (HEU) fuel to a low-enriched uranium
(LEU) fuel. The primary constraint for the project is that the
overall fuel plate dimensions and the current neutron flux
performance must remain unchanged. This allows minimal impact on
the facility and cost for the conversion, and provides transparency
to the HFIR customer base and research projects that depend on the
facility for isotopes and neutron flux. As a consequence, the LEU
design demands more accuracy and less margin in the analysis efforts
than the original design.
Several technical disciplines are required to complete this
conversion including nuclear reactor physics, heat transfer, fluid
dynamics, structural mechanics, fuel fabrication, and engineering
design. The role of COMSOL is to provide the fully-coupled 3D
multi-physics analysis for heat transfer, turbulent flow, and
structural mechanics of the fuel plates and flow channels. A goal
is for COMSOL to simulate the entire fuel element array of fuel
plates (171 inner, 369 outer). This paper describes the progress
that has been made toward development of benchmark validation models
of the existing HEU inner-element fuel plates.
