https://doi.org/10.1051/epjn/2025067
Regular Article
Neutronic analysis of accident tolerant fuel concepts in spectral shift regulation conditions
1
Laboratory of Nuclear Installation Safety, Lithuanian Energy Institute, Breslaujos st. 3, Kaunas, 44403, Lithuania
2
National Institute of Pedagogical Skills named after Abdulla Avloni, Tashkent, 100095, Uzbekistan
3
Gran Sasso Science Institute, Viale F. Crispi 7, L‘Aquila, 67100, Italy
* e-mail: dilmurod.tuymurodov@lei.lt
Received:
2
April
2025
Received in final form:
22
July
2025
Accepted:
22
September
2025
Published online: 28 October 2025
The study of Accident Tolerant Fuels (ATFs) has gained significant attention due to their potential to enhance the safety and reliability of nuclear reactors, especially under severe accident conditions. This work investigates the neutron-physical performance of ATF concepts in Light Water Reactor (LWR) using spectral shift regulation (SSR). The SSR mechanism, which adjusts the moderator-to-fuel ratio, by means of mechanical displacers that run in the guide tubes, enables spectral hardening during the initial cycle and softening toward the end, optimizing fuel utilization and reactor safety. Using collision probability method with the GETERA simulation tool and BNAB library, this study evaluates various ATF designs, including chromium-coated zirconium (CrZry), FeCrAl alloys, and SiC composites, combined with uranium silicide (U3Si2) and uranium nitride (UN) high density fuels. Key metrics such as infinite multiplication factor, nuclide inventory, and plutonium buildup are analyzed. Results demonstrate that SiC cladding paired with UO2 or U3Si2 fuels offers the best neutronic characteristics, requiring slightly lower uranium enrichment. Thin FeCrAl cladding, on the other hand, shows higher enrichment needs but still around enrichment level of the fuel in Light Water Reactors, when paired with combination with U3Si2. The integration of SSR in the LWR reactor improves burn-up efficiency while burning produced plutonium and lower natural uranium consumption, resulting in reduced waste. Among the ATF options studied, SiC cladding shows good promise for guide tube and displacer applications, due to their neutron transparency and thermal stability.
© D. Tuymurodov et al., Published by EDP Sciences, 2025
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
