Development and study of a microwave reflex-radar level gauge of the nuclear reactor coolant
The article considers the design of a microwave reflex-radar level gauge of the nuclear reactor coolant. The main advantage of the reflex-radar measurement principle is that it does not actually affect the accuracy when measuring the level of bubbles present, the coolant condensation and boiling as well as changes in its pressure, temperature and density. In addition, the design of the measuring transmitter is quite simple.
In this level gauge, a microwave waveguide made as a coaxial line is used as a transducer (measuring probe). The probe consists of a steel pipe with an external diameter of 20 mm and a central electrode; it is located vertically and immersed in a controlled coolant. The probe wave resistance is 50 ohms. The electrical diagram of the device is presented. The oscillograms of the received signals and the basic relationships explaining the level gauge operation are also given. The signals of the coaxial measuring probe have been examined in a liquid with a variable dielectric constant. The results of an experimental study of the level gauge operation in a water coolant at high parameters are given, i.e., at pressures up to 10 MPa and temperatures up to 310 °C. It has been shown that the device maintains its functional stability under these conditions. The level gauge’s readings practically do not require correcting when the coolant’s thermophysical properties are changed. The device is intended for use in the control and management systems of nuclear power plants as well as in fuel reprocessing plants.
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