A Corrosion Test Station for Improved Characterization and Examination Capabilities of Advanced Nuclear Reactor Fuels and Materials

Advanced nuclear reactor systems utilize liquid metal coolants, which requires that reactor component materials be corrosion resistant while maintaining safety, reliability, and performance criteria in normal reactor operation as well as in accident scenarios. Niowave, in collaboration with Los Alamos National Laboratory and the University of Michigan, is currently developing a hybrid fast/thermal spectrum subcritical testbed, coupled to a superconducting electron linac, to provide peak fast-spectrum neutron fluxes greater than 1015 n/cm2s in heavy- liquid metal environment. The facility will be used to test novel fuels, materials, instruments and components, reactor safety designs, provide data for reactor code development, and support the regulatory process for licensing novel technology.An initial proof-of-concept fast neutron source, driven by a superconducting linac and lead-bismuth eutectic (LBE) neutron converter already exists at Niowave. Additionally, Niowave’s Radioisotope Program established both the facilities and the NRC license to operate a subcritical uranium assembly and perform nuclear fuel reprocessing. In the hybrid subcritical testbed, LBE is used as a neutron converter and coolant. To determine compatible materials with LBE, materials such as niobium, austenitic steel (i.e., 316L), ferritic/martensitic steel (i.e., HT9), and ODS (i.e., MA956) steel have been tested in stagnant LBE up to 700 °C at Niowave.Niowave has decided to expand this work and develop a corrosion test station (CTS) using LBE for improved characterization and examination of advanced nuclear reactor fuels and materials. In Phase I, a detailed engineering design along with all the various components of the station will be completed. The corrosion test station will be built from stainless steel and operated at temperature up to 500 °C. In Phase II, the CTS will be built with parts made of Nb or Nb-SS bimetal for the sample test section and operated at temperatures up to 700 °C with flow velocities capable of exceeding 5 m/s. The samples include novel cladding and reactor structural materials, and actual nuclear fuel specimens (i.e., U, U-Zr, U-TRU-Zr, and UO2) or surrogates that will be tested for extended amount of time. Ultimately, this station will support the nuclear energy community’s fuels and materials qualification program by providing means to develop, characterize, and examine promising materials for advanced reactors.