Izvestia Vysshikh Uchebnykh Zawedeniy. Yadernaya Energetika

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

Development and study of a microwave reflex-radar level gauge of the nuclear reactor coolant

6/22/2018 2018 - #02 Nuclear power plants

Ivanov V. V. Teplyashin I. A. Timonin M.A.

DOI: https://doi.org/10.26583/npe.2018.2.02

UDC: 681.121

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.


  1. Glebovich G.V., Andriyanov A.V., Vvedenckij Y.V., Kovalev I.P., Krylov V.V., Ryabinin Y.A. Investigation of objects using picosecond pulses. Moscow. Radio i Svyaz’ Publ., 1984, 256 p. (in Russian).
  2. Vorontsov A.S., Frolov P.A. Pulse measurement of coaxial communication cables. Moscow. Radio i Svyaz’ Publ., 1985, 96p. (in Russian).
  3. Tarasov N.A. Using the method of pulse reflectometry for determination of damage of cablelines. Available at: http://reis.narod.ru/metod.htm (accessed Mar 10 2018) (in Russian).
  4. Jones S.B., Wraith J.M., Or D. Time domain reflectometry measurement principles and application. Hydrol Process. 2002, no. 16, pp. 141-153.
  5. Weiss M., Knochel R. Novel method of measuring impurity levels in liquid tanks. 1997 IEEEMTT&S International Microwave Symposium Digest. 1997, v. 3, pр. 1651-1654.
  6. Cataldo A., Tarricone L., Attivissimo F., Trotta A. A TDR Method for Real-Time Monitoring of Liquids. IEEE Transactions on Instrumentation and Measurement. 2007, no. 56, pp. 582-595.
  7. Trenkal E.I., Loschilov A.G. Measurement of liquid levels by pulse reflectometry (review). Proc. of the Tomsk GUSUR, 2016, v. 19, no. 4, pp.67-73 (in Russian).
  8. Jun G., Huigin Z., Hongyu Y., Hui Z. Design of guided wave radar level meter based on equivalent time sampling. Proc. of the IEEE Int. Conf. «Communications, Circuit and Systems (ICCCAS)». Chengdu, China, 15-17 Nov., 2013, v. 2, pp. 139-142.
  9. Xiaowen X., Zonghui L., Junkai G., Hongmin G. The principle and simulation of the TDR test. Proc. of the IEEE Int. Conf. «Microwave Techn. and Comp. Electromagnetics». Qingdao, China, 25-28 Aug., 2013, pp.47-51.
  10. Dozer B.E. Selfcalibrating liquid-level measuring device. Patent US, no. 3398578, 1968.
  11. Hook W.R. Apparatus and methods for time domain reflectometry. Patent US, no. 5726578, 1998.
  12. Reimelt R., Schroth H. Device for determining and/or monitoring the fill level of a product in a container. Patent DE, no. 1010945, 2002.
  13. Gravel J.L., Fandrey M.C. Tank seal for guided wave radar level measurement Patent US, no. 7255002, 2005.
  14. Instructions for installing and operating the BM100 level transmitter company KROHNE, 37 p. Available at: www.ste.ru/krohne/pdf/rus/russ_op_manualBM100.pdf (accessed Mar 10 2018) (in Russian).
  15. Cataldo A., De Benedetto E., Cannazza G. Broadband Reflectometry for Enhanced Diagnostics and Monitoring Applications. Springer Science & Business Media, 2011, 150 p.
  16. Nemarich C.P. Time domain reflectometry liquid level sensors. IEEE instrumentation & measurement magazine. 2001, v. 4, iss. 4, pp. 40-44.
  17. Teploenergetika i teplotechnika. Vol. 1. General questions. Section 7. Physico-chemical properties and technology solutions, p. 298. Moscow. MEI Publ., 1999, 528 p.
  18. Mel’nikov V.I., Ivanov V.V., Teplyashin I.A. The study of ultrasonic waveguide level gage of nuclear reactor coolant on the basic of reflex-radar principle. Izvestia vysshikh uchebnykh zavedenij. Yadernaya energetika. 2015, no. 4, pp. 26-35 (in Russian).

microwave reflex-radar level gauge water coolant at high temperatures and pressures (310 °C, 10 MPa) nuclear reactor power-generating equipment