Burst test experiments on tube for nuclear fuel cladding and other calculations

The SCK•CEN is developing a new type of nuclear reactor called MYHRRA, which is an ADS. Contrary to most reactors in use or in development in the world, the cladding of the fuel will be made in steel (T91) and not in Zircalloy. The aim of this study is to elaborate and validate an accurate burst test procedure that can be easy performed and that would give information on the maximum sustainable internal pressure prior permanent damage. The principle of the burst test is to burst a closed end cladding tube by slowly injecting highly pressurized oil into the specimen, at the operating reactor temperature. During the experiment, the pressure is acquired using a multimeter. Data are numerically post treated to obtain important parameter such as yield stress, elongation, burst pressur. A procedure has been developed and qualified to perform the experiment with an accurate control of pressure and with the avoidance of leakages. However, some problems at high temperature were identified; namely the used oil begins to degrade above 300°C and cannot be used for temperatures higher than 400°C. Moreover for safety reasons, it should be demonstrated that every component can sustain 500°C without permanent damage.