Accident Tolerant Fuel Cladding Materials for Light Water Reactors: Analysis of Neutronic Characteristics

Abstract

Nuclear reactor fuel is the basic component of all safety requirements associated with nuclear energy production. The neutronic characteristics of light water reactors with candidate accident-tolerant fuel cladding materials were investigated in this work to improve nuclear safety. The materials were chosen for their high-temperature strength, radiation resistance, and corrosion resistance, which will contribute to nuclear safety. The research was conducted using a deterministic neutronic code for reactor design and analysis. The neutronic properties of a light water reactor system with candidate cladding materials were analyzed and compared to those of the reference. The reference cladding material was Zircaloy-4, and the candidate fuel cladding materials examined were FeCrNi alloy, oxide dispersion strengthened steels of FeCrY2O3 and FeCrZrO2. The eigenvalues of the reactor were computed at various fuel temperatures and burnup stages. The results of the study revealed that employing candidate cladding materials led to a slightly hardened neutron spectrum, reducing initial excess reactivity and resulting in lower fuel burnup.  This can be compensated by adding fuel enrichment up to 6%., which yields burnup value of 42000 MWd/T, which is higher than the reference of 40000 MWd/T with a reduced gap in initial excess reactivity from 28.4% to 25.4%.  The candidate fuel cladding materials also showed better than reference reactivity loss properties in case of unwanted temperature increase. This demonstrated that the examined improved tolerant materials have the ability to increase the inherent safety of nuclear reactors.

Keywords

• atf cladding
• doppler coefficient
• neutronic characteristics
• nuclear safety
• oxide dispersed strengthened