Development of Modified Ring Tensile Test Technique for Fuel Cladding in Hot Cell (II)

The modified ring tensile test technique was proposed in order to evaluate mechanical properties of fuel cladding under hoop loading condition in hot cell. The hoop loading grip for the modified ring tensile test is designed such that a constant specimen curvature is maintained during deformation, and the gage section of ring specimen is located at the top of the half-cylinder(Φ8.08 mm). The interface between the outer surface of the half-cylinder and the inner surface of the ring specimen was lubricated by graphite lubricant(Molykote P37) in order to minimize the friction between this contact surface. The ring specimen design for ring tensile test is conducted to limit deformation within the gauge section and to maximize uniformity of strain distribution. The dimensions of the ring specimen are 5 mm in ring width, 3 mm in gage length, 2 mm in width of the gage section and 1 mm in radius of the shoulder part. The specially designed precision grinding machine was developed to machine the gage section at the ring segment with 5 mm in length, and the optimum machining conditions are determined. From the comparisons between the test results in this study and the other researcher's test results, we ensure that the proposed ring tensile test technique is suitable to evaluate the mechanical properties of fuel cladding in hoop direction quantitatively