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

ABSTRACT

The molten salt reactor (MSR) is one of the leading advanced nuclear reactor candidates to replace current nuclear reactor technologies in the U.S. Besides having more economical and reliable designs, MSRs are amenable to a closed fuel cycle, in which electrochemical reprocessing can be performed to recycle the used nuclear fuel. This review intends to provide information about potential waste forms for metal and salt waste streams from these salt-based nuclear processes. Metal waste streams arise from reactor components and structural materials. Salt waste streams are generated during reactor operations as fission products build up in salt-fuelled systems. Waste forms that have the highest waste loading and/or have shown the most commercial promise are discussed with an emphasis on the current state of efforts to understand the synthesis and chemical durability of metal and ceramic waste forms.

KEYWORDS:

• Molten salt reactors
• electrochemical reprocessing
• metal waste form
• salt waste form

Acknowledgements

This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under grant number DGE-1447692 to JM. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation, the U.S. Department of Energy, or the United States Government. This work was supported by the United States Nuclear Regulatory Commission (NRC) under Contract NRC-HQ-13-G-38-0027. Ms. Nancy Hebron-Israel serves as the NRC award program manager. This work was supported by the United States Department of Energy (DOE) under Contracts DE-NE0008563, DE-NE0008572, DE-NE0008889, DE-NE0008900. Kenny Osborne serves as the program manager for the DOE awards. The Pacific Northwest National Laboratory is operated by Battelle under Contract Number DE-AC05-76RL01830. The authors thank William Ebert of Argonne National Laboratory for use of Figures 3, 4, and 6 and contributions to Figures 8 and 10. Authors thank D.E. Holcomb and J. McFarlane of Oak Ridge National Laboratory for their helpful discussions and guidance on accuracy for the MSR concept drawings.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under grant number DGE-1447692 to JM. This work was supported by the United States Nuclear Regulatory Commission (NRC) under Contract NRC-HQ-13-G-38-0027. Ms. Nancy Hebron-Israel serves as the NRC award program manager. This work was supported by the United States Department of Energy (DOE) under Contracts DE-NE0008563, DE-NE0008572, DE-NE0008889, DE-NE0008900. Kenny Osborne serves as the program manager for the DOE awards. The Pacific Northwest National Laboratory is operated by Battelle under Contract Number DE-AC05-76RL01830; Office of Nuclear Energy.