The Korea Atomic Energy Research Institute's (KAERI) successful irradiation tests and positive inspection of high-density uranium silicide fuel indicate potential for high-enriched uranium to low-enriched uranium conversion of high-performance research reactors. It is aiming to bolster international nuclear non-proliferation efforts upon commercialization by reducing the use of high-enriched uranium (HEU).
KAERI worked with a plate-type uranium silicide fuel, with a high uranium density designed for research reactors. It has successfully completed irradiation tests and visual inspections. The uranium density of the test fuel is five point three grams per cubic centimeters, which is about ten percent higher than that of the current fuel in use. The visual inspection of the irradiated materials yielded positive observations.
Most material testing reactor (MTR) fuel assemblies utilize fuel plates with a uranium density of four point eight grams per cubic centimeter. The development of higher uranium-density fuels has become critical for high-performance research reactors. This research supports the conversion from HEU fuel to low-enriched uranium (LEU) fuel in the USA and Europe. KAERI initiated research and development on these high uranium-density silicide fuels in 2020. They focused on fuel plates with densities up to five point three grams per cubic centimeter.
For the fuel intended for use in high-performance research reactors, KAERI developed uranium silicide (U3Si2) spherical-particle powder using the atomization method. It has utilized it for the development of various research reactor fuels. KAERI is involved in the high-density atomized LEU U3Si2 MTR fuel qualification campaign. The campaign is known as the ‘KAERI High-Density Atomized Silicide Fuel Qualification Irradiation Project (KIMQI) Fuel Qualification Project of High-Density Atomized Silicide Fuel.’ The Belgium's Nuclear Research Centre (SCK-CEN) was part of the collaboration.
The qualification campaign, which began in 2021, consists of two phases. First, the KIMQI-FUTURE test, which ran from 2021 to 2023 to confirm basic performance. Second, the KIMQI-GTA (Generic Test Assembly) to evaluate performance under high heat flux and high burnup conditions. The KIMQI-GTA irradiation procedure was recently completed, achieving a peak heat flux of four hundred and seventy watts per square centimeter and a peak local burnup that reached seventy four percent of the initial fissile content. The visual inspection results showed that no abnormal conditions were experienced during the irradiation test. This fact is a positive indicator for the potential use of the developed high-density fuel in high-performance research reactors. The final qualification report included Post-Irradiation Examination (PIE) test results. The report is expected to be available by the end of 2025.
Once this technology is commercialized, it will enable the replacement of HEU with LEU in high-performance research reactors. This will significantly contribute to the international nuclear non-proliferation effort.
In December of 2022, KAERI signed a memorandum of understanding (MoU) with Poland's National Centre for Nuclear Research. The MoU was an agreement to supply nuclear fuel for Poland's research reactor MARIA using high-density low-enriched uranium U3Si2 plate-shaped nuclear fuel manufacturing technology. The MoU focuses on the South Korean institute interest in supplying test fuels to MARIA for the qualification of nuclear fuel supply.