Multiaxial creep testing device for nuclear fuel claddings

Mechanical properties and creep resistance are among the key issues in the selection of fuel cladding materials for future Gen-IV nuclear reactor applications. As for today's nuclear reactors, the Fukushima accident has increased the interest in accident-tolerant fuel cladding materials. Thin-walled fuel cladding tubes may exhibit anisotropic creep properties due to the manufacturing process. A newly developed Pneumatic Loading Apparatus (PLA) is capable of testing the multiaxial creep properties of thin-walled tubular specimens with internal pressure and an additional axial force. Because of its innovative design, the PLA is moveable and can be implemented in testing in extreme environments. The system functionality and accuracy was demonstrated by two biaxial creep tests performed on austenitic stainless steel DIN 1.4970 and E110 zirconium alloy specimens. Both materials showed anisotropic creep behavior and the PLA testing concept and equipment proved its capability to perform reliably and accurately biaxial creep testing of fuel cladding materials