Authors & Affiliations
Kharitonova N.L., Gurbanova Sh.A.
National Research Nuclear University “MIFI”, Moscow, Russia
Kharitonova N.L. – Leading Researcher, Cand. Sci. (Tech.).
Gurbanova Sh.A . – Postgraduate Student, National Research Nuclear University “MIFI”. Contacts: 115409, Moscow, Kashirskoe shosse, 31. Tel.: +7 (499) 324-77-77; е-mail:
Abstract
The article is devoted to the choice and substantiation of thermodynamic data necessary for the development of calculation codes for modeling the physicochemical processes of the interaction of a water coolant with structural materials in the conditions of supercritical water cooled reactors. The ion product of water, which determines the balance between hydrogen and hydroxide ions, is a reference property in the chemistry of aqueous solutions, including a fundamental constant for calculating the hydrogen index of a coolant, pH, which is one of the most important integral indicators of corrosion aggressiveness of the water and aqueous solutions. In the paper, the calculation of the high-temperature pHt at the point of neutrality of pure water in the vicinity of the critical region and at supercritical values of temperature and pressure is carried out. As the initial thermodynamic data for calculating pHt, the main existing correlations for the ion product of water – Kw are analyzed depending on temperature and pressure (density), in which Kw is a dimensionless value at a unit molality of water for a standard state m0 = 1 mol kg−1. Differences in pHt values calculated using analytical correlations for pKw (pKw ≡ −lg(Kw)) of Marshall – Frank (recommendations of the International Association for the Properties of Water and Steam (IAPWS), 1981), Bandura – Lvov (IAPWS, 2006 – 2019), as well as the formulations of Tremain – Arsis (2020) were quantified. The last formulations were obtained on the basis of new experimental data – precision measurements of the electrical conductivity of high purity water. A quantitative assessment was made of the effect of the ion product of water, calculated according to the indicated formulas, on the pHt values at the neutral point of water – in the temperature range up to 600°C in the near critical region and at supercritical parameters at a pressure of 25 MPa. The article is intended to help in the development of effective measures to mitigate the corrosion and corrosion-erosion processes in the water coolant, as well as to minimize the formation of deposits on the surface of equipment operating in the region of near-critical and supercritical parameters.
Keywords
supercritical water cooled reactor, safety, water coolant, high-temperature hydrogen index pH, ion product of water, water chemistry, concentration, experimental data, electrolytic dissociation of water, physical and chemical properties of water coolant
Article Text (PDF, in Russian)
UDC 621.039.58
Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2022, no. 4, 4:20