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Electrochemical System for Molten Salt Analysis

Tierra West & Victory Egot for the NEXT Lab Collaboration

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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What is the NEXT Lab?

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"Finding global solutions to the world’s most critical needs"

Clean water

Clean Energy

Medical isotopes

Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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What is the NEXT Lab?

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100% of countries with a poverty rate over 25% use less than 10,000kWh. As we increase the amount of kWh in a country the poverty rate decreases .

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Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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How does CAS fit in?

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Chemical analysis systems

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Monitor:

  • Components of the salt
    • Decay products (molybdenum-99)
  • Components of headspace gas
    • MoF6, Iodine-131
  • Electrochemical potential of the salt
    • Corrosion

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Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Why is this important?

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𝑀 → 𝑀𝑛+ + 𝑛𝑒− (1)

𝑅𝑛++ 𝑛𝑒− → 𝑅 (2)

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  • Radioactive fluoride/FLiNaK environments
  • Fission products/contaminants → Corrosion
  • Salt takes electrons from steel
    • Chromium oxidized
    • Contaminants reduced
  • Electrochemical potential tracks these reactions

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Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Corrosion

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Stainless Steel 316

FLiNaK

Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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System Requirements

  • Airtight
  • Hold FLiNaK and withstands its high temperatures (700℃)
  • Insulated electrodes with boron nitride
  • 4-5 electrodes
  • Thermocouple
  • Gas ports for a cover gas

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Electrochemical System for Molten Salt Analysis

​

© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Design 1

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Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Initial Design

Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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CAD Drawing

Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Final Product

Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Things to know - Design 1

  • Intermediate model

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  • All electrodes are separate
    • Can be removed and interchanged

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  • Will inform the final design of design 2

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Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Design 2

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Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Initial Design

Electrochemical System for Molten Salt Analysis

​

© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Things to know- Design 2

  • Modeled after the system of the chemical engineer Nathaniel Hoyt.

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  • Electrodes are compact and fixed.
    • Serves a great advantage when incorporated in the test loop.

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  • Electrodes used in this system will be based on the results from the experiment done with the first design.

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Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Open Circuit Potential

  • The potential difference of the sample when no current is flowing.

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  • Monitor electric potential of FLiNAK
    • Potential determines corrosive ability

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  • 2 electrodes
    • 1 reference electrode
    • 1 sensing electrode

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Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Cyclic Voltammetry

  • Cyclic voltammetry is important for quantitative and qualitative measurements.
  • Platinum quasi-reference electrode
    • Reversibility
    • Stability and reproducibility of the potential
    • Stability of the electrode material
    • High conductivity (low impedance)
    • Compatibility with the type of measurement (Shay, 2017).
  • Tungsten
  • Nickel
  • Molybdenum

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Electrochemical System for Molten Salt Analysis

​

© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Redox Control

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(Hoyt, 2019)

Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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What’s Next?

Soon…

  • Testing (works and no leaks)
  • Determining best redox control method

Later...

  • Installation into the loop

Beyond our time...

  • Installation into the reactor for online monitoring of molten salt.

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Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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References

  1. Shay, W. N. Electrochemical Sensor Development for Fluoride Molten Salt Redox Control. Thesis, The Ohio State University, Columbus, OH, 2017.
  2. Hoyt, N. C.; Williamson, M. A.; Willit, J. L. Multiple Sensor for Concentration and Depth Measurements in Molten Salt. US20190285565, September 19, 2019.
  3. Hoyt, N. C.; Guo, J.; Stricker, E. A.; Williamson, M. A. Online Monitoring of Molten Salt Reactors, NRC Advanced Reactor Workshop 2019, December 11, 2019; UChicago Argonne, LLC.

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Electrochemical System for Molten Salt Analysis

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© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.

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Acknowledgement

Nuclear Energy eXperimental Testing Lab Staff and Students

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The ACU Department of Chemistry and Biochemistry

Dr. Kim Pamplin & Alli Mae Berry

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Electrochemical System for Molten Salt Analysis

Electrochemical System for Molten Salt Analysis

​

© Abilene Christian University

The content of this presentation is the propriety and confidential information of ACU/NEXT Lab.

It is not intended to be distributed to any third party without the written consent of ACU/NEXT Lab.