In-Situ Neutron Radiography with Hydrogenated Tensile Samples in the INCHAMEL Facility
摘要
In Light Water Reactors, fuel rod cladding tubes made of zirconium alloys undergo an oxidation process where a certain fraction of hydrogen may penetrate into the cladding. Hydrogen precipitates as hydride in the metallic matrix during cooling in the post-operation phase. An applied tensile force in the elastic range increases the hydrogen solubility and diffusivity and thus may initialise a reorientation process of hydrides that could be destructive for the metal. During long-term dry storage conditions, the stress influence in the elastic range on the zirconium claddings seems to be relevant, but not quantified yet. This paper presents in-situ neutron radiography experiments of hydrogenated zirconium tensile samples under the influence of different elastic tensile stresses. The experiments were conducted during the commissioning of the In-situ Neutron radiography CHAmber for tests under MEchanical Load facility, a tensile testing machine with an inductive heating system. The stress influence on hydrogen movements in the elastic range for short time frames (hours) was shown to be negligible. Only under the influence of plastic tensile stresses, hydrogen movements from regions with lower to higher stress were observed. Nevertheless, the first results show that the new facility can be successfully used for investigations of the influence of elastic stresses on the hydrogen diffusion and solubility in zirconium. However, the duration of the experiments and/or the resolution during the neutron imaging have to be optimised.