Izvestiya vuzov. Yadernaya Energetika

The peer-reviewed scientific and technology journal. ISSN: 0204-3327

Research Justifying an Enhanced Electrochemical Hydrogen Detector in Sodium

5/18/2026 2026 - #02 Physics and Technology of Nuclear Reactors

Alekseev V.V. Borisov V.V. Kamaev A.A. Ganichev N.S. Savankov V.G.

DOI: https://doi.org/10.26583/npe.2026.2.05

UDC: 621.039.534.63

Monitoring of the hydrogen content in sodium is one of the important safety tasks during operation of a reactor facility with a fast neutron reactor with a sodium coolant. Timely indication of a small leak makes it possible to localization of the accident before the destruction of the steam generator tubes. A key element of the hydrogen monitoring system is a sensor that continuously measures the concentration of hydrogen in sodium. This paper examines the design and operational principle of an electrochemical hydrogen sensor in sodium. A semi-empirical expression for calculating the electromotive force (EMF) has been proposed. This formula incorporates two key coefficients: k1, associated with the water vapor pressure in the steam chamber, and k2, which characterizes the deviation from ideality in the oxygen sensor. Experimental data revealed a significant scatter in the values of the k1 coefficient, confirming the imperfection of water vapor stabilization. The minor variations observed in the k2 coefficients across different sensor units are attributed to the individual characteristics of the installed electrochemical oxygen cells. An enhanced sensor design featuring a palladium membrane is considered. This membrane serves to separate the steam chamber from the chamber equipped with a nickel membrane. Calculations were performed to model the dynamics of hydrogen pressure changes within the steam chamber for both the standard nickel-membrane sensor and its advanced modification. The time required to reach 67% of the equilibrium hydrogen pressure was determined for various chamber volume ratios. The analysis demonstrates that for chamber volumes of less than 1 ml and a membrane area ratio of S1/S2 < 20, the incorporation of the palladium membrane does not lead to a reduction in sensor inertia. However, its critical function is to prevent oxidation of the nickel membrane by effectively blocking the permeation of water vapor. The obtained results can be utilized to optimize the design of Electrochemical Hydrogen Detectors in Sodium (EKhDV-N) in automatic steam generator protection systems (SAZ PG) as part of the reactor facility with a fast sodium reactor in order to reduce inertia and increase the service life of the sensors.

References

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sodium hydrogen sensor sodium oxygen sensor transducer element solid electrolyte reference electrode nickel membrane hydrogen partial pressure electrochemical sensor EMF vapor-water chamber fast sodium reactor steam generator palladium coating automatic steam generator protection system thermodynamic activity empirical coefficients

Link for citing the article: Alekseev V.V., Borisov V.V., Kamaev A.A., Ganichev N.S., Savankov V.G. Research Justifying an Enhanced Electrochemical Hydrogen Detector in Sodium. Izvestiya vuzov. Yadernaya Energetika. 2026, no. 2, pp. 70-82; DOI: https://doi.org/10.26583/npe.2026.2.05 (in Russian).

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