Imaging and hydrogen analysis by SIMS in zirconium alloy cladding: a dual ion beam approach

Abstract

Zirconium-based alloys are used as fuel cladding material in nuclear power plants. During the reactor operation, the material is oxidized by the water (reactor coolant), and hydrogen gas is formed. The released hydrogen gas, which partly diffuses into the zirconium alloy, forms hydrides when the hydrogen solubility limit is exceeded. This may result in blistering and cracking of the claddinga phenomenon commonly known as hydrogen embrittlement. Both corrosion and H-uptake phenomena are limiting factors, which can reduce the time of life of cladding under irradiation in a power plant. This study concerns a preliminary investigation of hydrogen by SIMS in a hydrogenated but not-irradiated Zircaloy-4 sample in order to develop a better understanding of hydrogen ingression in high burn up irradiated cladding tubes. Although hydrogen can be easily detected using the SIMS technique, any contamination source of hydrogen must be well identified and minimized during the SIMS measurements. In this work, we have analyzed a hydrogenated (135 wppm in bulk) Zircaloy-4 cladding specimen. In the first step, the sample's surface has been presputtered with cesium ions. Thereafter, H À ions yield images have been acquired analyzing the sample with a gallium primary ion beam. Using this dual beam approach, the hydride precipitates present in the sample have been clearly identified and analyzed.

Retrospect on Zirconium Laves Phases ZrZn2 and ZrAl2 with Their Physicochemical Properties and Perspective for Possible Hydrogen Storage Reactions

“…Zirconium alloys are known to have a good corrosion resistance and its incorporation in intermetallic alloys or adjunct substitution provides improved protection against oxide growth depending on alloying concentration (Féron, 2012;Samaras, 2011). This makes Zr-based alloys valuable for different applications like solid-gas reactions or others hydrothermal energy conversions (Mine et al, 2014;Kumarn et al, 2013;Lototskyy et al, 2018;Matsuyama et al, 2018).…”

Use of Secondary Ions Mass Spectrometry (SIMS) for Cladding Materials Post-Irradiation Examination (PIE)

“…The investigation of hydrides is more challenging and a new method has been recently developed after an improvement of the instrument capabilities (up-grade), allowing to perform hydrogen ion mapping with 25 keV 69 Ga+ primary ions after 10 keV 133 Cs + ions bombardment (Fig.3) . The first results on non-irradiated hydrogenated samples have been presented last year [4]. .…”