The results of geothermal and geoelectric studies in the regions of Rivne, Khmelnitsky and Uzhno Ukrainsk NPPs

Abstract

The main task of the work was to present for the first time the results of geothermal and geoelectric studies obtained in the tectonosphere department and comparing them with other geological and geophysical data. Unfortunately, geothermal data near all nuclear power plants are scarce. Despite this, a possible increasing of heat flow (HF) near Khmelnitsky NPP can be assumed. Such an assumption is correlated with data on increased values of modern vertical movements of the Earth’s surface. A comparison of the position of nuclear power plants with faults active in past 3 million years shows that all nuclear power plants are located near the Kamen-Kashirsk-Yalta fault. Khmelnitsky NPP is located near the intersection of the latter with the Khust-Koretsky fault, and the South Ukrainian — near the Ananyevsky-Khadzhibeysky fault. Based on the analysis of Earthquake Catalogs presented in the Seismological Bulletins of Ukraine for 1999—2016 and international seismicity databases, a map of the seismicity of nuclear power plant areas has been built. The most representative data (a significant number of earthquakes) are located south of the Khmelnitsky NPP, where they are well explained by the presence of the Ternopol heat flow anomaly. Based on the 2D inversion of magnetotelluric research data, the construction of a volumetric geoelectric model of the territory of Ukraine from 36° to 24° East in the earth's crust and at the top of the mantle, objects with less resistivity than 120 Ohm · m (OLR) and blocks of rocks with resistance of more than 10,000 Ohm · m, which characterize rocks with high basicity and lowest porosity, are distinguished. In all regions of NPPs, there are OLR that are consistent with fault zones active in the last 3 million years. In the regions of the Rivne and Khmelnitsky NPP, the OLR are consistent with areas of an anomalous increase in the average velocity gradients of neotectonic movements. According to the totality of the data reviewed, the most unfavorable, from the point of view of stability of the Earth's interior, deep structure is noted in the area of the Khmelnitsky NPP.