Immersion Corrosion Testing of Iron-Chromium-Aluminium Tubes under Simulated Light Water Nuclear Reactors Normal Operation Conditions

摘要

The US Department of Energy is funding research to improve the operation safety of existingGeneration III light water reactors nuclear power plants. General Electric, Oak Ridge NationalLaboratory and Nippon Fuel Development are proposing to replace the current zirconium-basedcladding using iron-chromium-aluminum alloys (FeCrAl). It is important to characterize the behaviorof the FeCrAl materials, since they were never used before in nuclear applications. Thecharacterization includes the behavior of the FeCrAl cladding in the entire fuel cycle, from powergeneration to used fuel disposition. The current work is related to the corrosion resistance ofFeCrAl in pure water at temperatures of 288°C to 330°C under hydrogen and oxygen conditions.The specimens tested were tube segments of the fuel cladding geometry and microstructure andwith a wall thickness of less than 0.5 mm. Mass change measurements of the tubes wereconducted every three months for a total period of one year and compared with the mass changesof Zircaloy-2 tube segments. Four types of specimens were tested including tubes of APMT, C26Mand two geometries of NFD ODS FeCrAl. The tested FeCrAl offered a good resistance tocorrosion under reactor normal operation conditions by the development of a thin and protectivechromium oxide on the surface. The FeCrAl specimens had a slight mass loss under the hydrogentested conditions.