Title: Neutronic Analysis on Potential Accident Tolerant Fuel-Cladding Combination U$_3$Si$_2$-FeCrAl,
Abstract: Neutronic performance is investigated for a potential accident tolerant fuel
(ATF),which consists of U$_3$Si$_2$ fuel and FeCrAl cladding. In comparison
with current UO$_2$-Zr system, FeCrAl has a better oxidation resistance but a
larger thermal neutron absorption cross section. U$_3$Si$_2$ has a higher
thermal conductivity and a higher uranium density, which can compensate the
reactivity suppressed by FeCrAl. Based on neutronic investigations, a possible
U$_3$Si$_2$-FeCrAl fuel-cladding systemis taken into consideration. Fundamental
properties of the suggested fuel-cladding combination are investigated in a
fuel assembly.These properties include moderator and fuel temperature
coefficients, control rods worth, radial power distribution (in a fuel rod),
and different void reactivity coefficients. The present work proves that the
new combination has less reactivity variation during its service lifetime.
Although, compared with the current system, it has a little larger deviation on
power distribution and a little less negative temperature coefficient and void
reactivity coefficient and its control rods worth is less important, variations
of these parameters are less important during the service lifetime of fuel.
Hence, U$_3$Si$_2$-FeCrAl system is a potential ATF candidate from a neutronic
view.