Characterization of Irradiated Metal Waste from the Pyrometallurgical Treatment of Used EBR-II Fuel

Abstract

As part of the pyrometallurgical treatment of used Experimental Breeder Reactor-II fuel, a metal waste stream is generated consisting primarily of cladding hulls laden with fission products noble to the electrorefining process. Consolidation by melting at high temperature [1873 K (1600°C)] has been developed to sequester the noble metal fission products (Zr, Mo, Tc, Ru, Rh, Te, and Pd) which remain in the iron-based cladding hulls. Zirconium from the uranium fuel alloy (U-10Zr) is also deposited on the hulls and forms Fe-Zr intermetallics which incorporate the noble metals as well as residual actinides during processing. Hence, Zr has been chosen as the primary indicator for consistency of the metal waste. Recently, the first production-scale metal waste ingot was generated and sampled to monitor Zr content for Fe-Zr intermetallic phase formation and validation of processing conditions. Chemical assay of the metal waste ingot revealed a homogeneous distribution of the noble metal fission products as well as the primary fuel constituents U and Zr. Microstructural characterization of the ingot confirmed the immobilization of the noble metals in the Fe-Zr intermetallic phase.

Molten salt reactors and electrochemical reprocessing: synthesis and chemical durability of potential waste forms for metal and salt waste streams

“…Westphal and co-workers at INL reported the development and characterisation of the first production-scale irradiated metal waste ingot in 2015, produced from used EBR-II fuel using a vacuum induction furnace in the Materials and Fuels Complex Hot Fuel Examination Facility [85]. The ingot contained Fe-based fuel cladding with NMFPs (Mo, Ru, Rh, Tc, Pd, and Te), as well as U and Zr from fuel adhering to the cladding.…”

Prioritized List of Research Needs to support MRWFD Case Study Flowsheet Advancement

“…This process has been developed and deployed for DOE sodium bonded fuel treatment at Idaho National Laboratory as described in the Metal Waste Form Handbook (Abraham et al 1999) and demonstrated full scale as described in Characterization of Irradiated Metal Waste from the Pyrometallurgical Treatment of Used EBR-II Fuel. (Westphal et al 2013) The process and qualification activities for this waste form are all based on 316 SS based fuel cladding, while the reference (and most likely) cladding for FR fuel is HT-9. The research needs include 1.…”

Technetium Immobilization Forms Literature Survey

“…Larger 60-kg ingots have been produced as part of a waste form qualification effort (Frank et al 2007). A full-scale ingot of 43.2 kg was recently produced with actual metal fuel cladding wastes (Westphal et al 2013).…”