scholarly journals Quantitative prediction of rare earth concentrations in salt matrices using laser-induced breakdown spectroscopy for application to molten salt reactors and pyroprocessing

Author(s):  
Gregory Hull ◽  
Hugues Lambert ◽  
Kiran Haroon ◽  
Paul Coffey ◽  
Timothy Kerry ◽  
...  

Pyroprocessing of spent nuclear fuels is an electrochemical separation method where spent metallic fuel is dissolved in a molten salt bath to allow uranium (U) and plutonium (Pu) to be isolated from fission products (FPs) and other impurities.

Author(s):  
Ammon Williams ◽  
Supathorn Phongikaroon

Pyroprocessing of used nuclear fuel has shown potential as an alternative fuel reprocessing technology to the traditional aqueous technology. Having a clear picture of the actinide, fission product, and rare-earth elements within the salt in realtime is important from processes control, efficiency and material safeguards perspectives. However, measuring the molten salt electrolyte composition within the system is challenging due the high temperature and radiation involved. Laser induced breakdown spectroscopy (LIBS) has been proposed to measure the molten salt composition via a static liquid surface or solid surface approach. These approaches can yield compositional results near real-time; however, concerns with sample homogeneity, splashing, and poor repeatability present significant challenges. A novel molten salt aerosol-LIBS system has been developed to mitigate some of the aforementioned challenges. Here, modifications to the system using a 1-jet nebulizer and sampling chamber are being discussed. Preliminary results demonstrate the advantages and success of the modifications. Experiments were conducted to optimize the spectrometer gate delay and results indicate that the optimal gate delay is greater than 9 μs. In addition, the percent relative standard deviations (%RSD) for this system were found to be approximately 7%.


2018 ◽  
Vol 72 (7) ◽  
pp. 1029-1039 ◽  
Author(s):  
Ammon Williams ◽  
Supathorn Phongikaroon

In this current study, the molten salt aerosol–laser-induced breakdown spectroscopy (LIBS) system was used to measure the uranium (U) content in a ternary UCl3–LiCl–KCl salt to investigate and assess a near real-time analytical approach for material safeguards and accountability. Experiments were conducted using five different U concentrations to determine the analytical figures of merit for the system with respect to U. In the analysis, three U lines were used to develop univariate calibration curves at the 367.01 nm, 385.96 nm, and 387.10 nm lines. The 367.01 nm line had the lowest limit of detection (LOD) of 0.065 wt% U. The 385.96 nm line had the best root mean square error of cross-validation (RMSECV) of 0.20 wt% U. In addition to the univariate calibration approach, a multivariate partial least squares (PLS) model was developed to further analyze the data. Using partial least squares (PLS) modeling, an RMSECV of 0.085 wt% U was determined. The RMSECV from the multivariate approach was significantly better than the univariate case and the PLS model is recommended for future LIBS analysis. Overall, the aerosol-LIBS system performed well in monitoring the U concentration and it is expected that the system could be used to quantitatively determine the U compositions within the normal operational concentrations of U in pyroprocessing molten salts.


Author(s):  
Wenkun Zhu ◽  
Xiaohui Li ◽  
Rui Sun ◽  
Yao Zhang ◽  
Yonghong Yan ◽  
...  

With the separation of the initial pyrolysis of coal and the laser ablation interaction, mineral-element migration upon pyrolysis and quantitative prediction of volatiles were investigated by laser induced breakdown spectroscopy (LIBS).


2019 ◽  
Vol 34 (5) ◽  
pp. 884-890 ◽  
Author(s):  
Tianbing Chen ◽  
Linying Zhang ◽  
Lin Huang ◽  
Muhua Liu ◽  
Jinyin Chen ◽  
...  

The PSO-SVM method shown here, for the analysis of LIBS spectral data, provides much better fitting results and prediction accuracy than siPLS and MLP-ANN models for the quantitative prediction of heavy metal content in pork.


2014 ◽  
Vol 68 (9) ◽  
pp. 937-948 ◽  
Author(s):  
Arel Weisberg ◽  
Rollin E. Lakis ◽  
Michael F. Simpson ◽  
Leo Horowitz ◽  
Joseph Craparo

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