REDOX PROCESSES AS THE BASIS OF POTENTIOMETRIC METHODS FOR CONTROL COOLANTS STATE OF NUCLEAR POWER SYSTEMS

Authors & Affiliations

Pityk A.V., Arnol'dov M.N.
A.I. Leypunsky Institute for Physics and Power, Obninsk, Russia

Abstract

In the modern technology of liquid-metal and molten salt coolants potentiometric method is one of the most promising methods for the quantitative analysis of impurity content and corrosion process control. The key concept of this analytic method is the «redox», which is a measure of the depth of oxidation-reduction interaction. This article gives an overview of existing research in field of control of the state the liquid-metal and molten salt coolants by means of various modifications of potentiometric method of analysis. Currently, one of the ways to control of impurity content in liquid-metal coolant associated with the use of electrode, wherein the solid electrolytes (e.g. ZrO2) are used as a conductive membrane. Within the bounds of the research for the control of oxygen content in the molten eutectic alloy of Pb-Bi and Pb there is a considerable experience in the application of electrochemical cells of this kind. It is also known about the experimental work related with creation of a galvanic cell for sodium coolant. In respect of molten salt coolants redox potential control is one of the basic methods for corrosion process monitoring. Recent research work in this issue are directed on three main areas: 1) redox-control by use of metallic beryllium immersed in the salt, as an active redox agent; 2) control of oxide formation by use of high purity He cover gas; 3) use of U(III)/U(IV) (i.e. UF3/UF4) ratio to control optimum oxidation state (redox potential) in fuel-salt.

Keywords
potentiometric method, redox-potential, EMF method, oxygen activity, liquid-metal coolant, molten salt coolant, sodium, lead, corrosion, solid electrolyte, reference electrode

Article Text (PDF, in Russian)

References

UDC 621.039.534

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants", issue 2, 2014