Irradiation performance of U3Si LEU fuels in HANARO

To verify the irradiation performance of the HANARO fuel at a high power and a high burnup, in-pile irradiation tests were performed. Two test fuels for a higher burnup irradiation and one test fuel for a higher linear heat rate had been designed and fabricated. All the test fuel assemblies were made of 6 fuel elements located in the outer ring of the hexagonal fuel assembly and 30 aluminum dummy elements. The test fuel assemblies were irradiated in the HANARO core. The maximum discharged burnup and linear power were 69.9 at% average and 85.5 at% peak with an 83 kW/m average and 121.6 kW/m peak, respectively. Detailed nondestructive and destructive PIE, such as the measurement of the burnup distribution, fuel swelling, clad corrosion, dimensional changes, fuel rod bending strength, micro-structure, etc., were performed. It was verified through the irradiation tests that the HANARO fuel maintains a proper in-pile performance and integrity even at a high power of 121 kW/m and up to a high burnup of 85 at%. (author)