ELECTROCHEMICALLY-MODULATED SEPARATIONS FOR SAFEGUARDS MEASUREMENTS
A critical objective of materials accountability in safeguards is the accurate and timely analysis of fuel reprocessing streams to detect both abrupt and prolonged diversions of nuclear materials. For this reason both on-line nondestructive (NDA) and destructive analysis (DA) approaches are sought-after. Current methods for DA involve grab sampling and laboratory based column extractions that are costly, hazardous, and time consuming. While direct on-line gamma measurements of Pu are desirable, they are not possible due to contributions from other actinides and fission products. Researchers at Pacific Northwest National Laboratory are currently investigating electrochemically-modulated separation (EMS) as a straightforward, cost-effective technology for selective separation of Pu or U from aqueous reprocessing streams. The EMS selectivity is electrochemically controlled and results from the sorption of Pu4+ and U4+ redox states onto the anodized target electrode, allowing for selective accumulation of U or Pu from nitric acid streams to be turned “on” or “off.” It is envisioned that this technology can be utilized to isolate Pu for both NDA and DA analysis. For the NDA approach, rapid Pu analysis by gamma-ray spectroscopy could be performed after chemical clean-up of activation and fission products by EMS. Likewise, in the DA approach, EMS could be used to retain and concentrate the Pu in nanogram quantities on the electrode surface to be transported to the lab for analysis using high precision mass spectrometry. Due to the challenges associated with complex matrices, a systematic investigation of the redox-dependent accumulation of Pu using EMS was necessary, and results will be presented. Approaches to mitigate interelement effects using large surface area cells will also be discussed. The EMS chemistry and spectroscopy for Pu isolation and measurement will be presented, proof-of-principle measurements will be described, and the application of this approach for materials accountability will be discussed.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1004518
- Report Number(s):
- PNNL-SA-73282; NN2001000; TRN: US1100696
- Resource Relation:
- Conference: Proceedings of the 51st Annual Meeting of the Institute of Nuclear Materials Management, July 11-15, 2010, Baltimore, Maryland
- Country of Publication:
- United States
- Language:
- English
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