Abstract
Electrochemical reprocessing (also commonly known as pyroprocessing) of used nuclear fuel is an alternative to aqueous reprocessing that confers a number of advantages, including the ability to process more recently discharged fuel, smaller resultant waste volumes, and the lack of isolation of plutonium in the product stream. While electrochemical reprocessing systems have seen a significant research and development effort, nuclear safeguards and the security of these systems remain underdeveloped, particularly given the significant differences in operating environment and process flow sheet compared with established aqueous methods. In this paper we present an overview of the current state of the art for several of the most promising candidate techniques for material accountancy and process monitoring measurements for electrochemical separations facilities for used nuclear fuel, specifically passive radiation signatures (gamma spectroscopy, neutron spectroscopy, alpha spectrometry, calorimetry, and microcalorimetry), active radiation signatures (X-ray interrogation and its derivatives, high-resolution X-ray, k-edge densitometry, and hybrid k-edge densitometry; laser-induced breakdown spectroscopy; active neutron interrogation and neutron coincidence counting; inductively coupled plasma mass spectrometry; and optical measurements such as ultraviolet visible spectroscopy, near-infrared spectroscopy, and Raman spectroscopy), and control and process state variable monitoring (cyclic voltammetry and bulk measurements such as level and density, load cell forces, and off-gas monitors). This assessment includes an evaluation of each measurement’s respective modality (i.e., whether the measurement relates to elemental, isotopic, or other properties), published best estimates of measurement precision, measurement latency, and an overall evaluation of each technique’s level of technical maturity. Additionally, this study assesses the most likely locations within the pyroprocessing flow sheet where measurements may be deployed, the physical information required to properly capture the behavior of such measurements, and potential modeling strategies for such measurements. This latter component thus serves to inform future development of process monitoring models in existing and proposed electrochemical separations simulation models.
Original language | English |
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Pages (from-to) | 1803-1826 |
Number of pages | 24 |
Journal | Nuclear Technology |
Volume | 206 |
Issue number | 12 |
DOIs | |
State | Published - 2020 |
Externally published | Yes |
Funding
This work was supported by a Nuclear Energy University Programs grant sponsored by the U.S. Department of Energy, Office of Nuclear Energy, award number DE-NE0008553. The authors likewise wish to gratefully acknowledge the support and assistance of Benjamin Cipiti and Nathan Shoman of the Sandia National Laboratory.
Keywords
- Pyroprocessing
- electrochemical separations
- material accountancy