Roughness of the nuclear reactor piping inner surface depending on operating time
UDC: 621.644, 621.9.08
During operation of nuclear reactors, there are various factors that affect the NPP piping leading to erosion of the pipe inner surface and its increased microrelief (roughness). Metal corrosion occurs and propagates faster on the surface having a higher value of the roughness parameter. Failures through erosive wear of the parent metal take place predominantly in the pipe bending area. The roughness of the pipe inner surface has a sizeable effect on the signal attenuation in the process of the pipe wall ultrasonic inspection. Defective main pipeline segments were cut out as part of preventive maintenance from which samples having different operating times were taken. Five defective pipe segments of the austenitic 12Kh18N10T-grade steel cut out from a high-pressure preheater’s piping and defective pipe segments of the perlite-class grade 20 steel with different operating times were used to determine experimentally the actual value of the pipe inner surface roughness. In addition, one piece of a new ∅273×12 pipe of 12Kh18N10T steel and one piece of a ∅159×6 pipe of grade 20 steel were cut out. The inner surface roughness in different segments was measured. Dependences of the roughness value on the operating time and the pipe segment type were obtained. As the result of the study, company specimens were obtained the insides of which had the surface roughness being in accordance with the different pipe operating times. This made it possible to take into account the effects of the pipe inner surface roughness on the signal attenuation in the process of the weld integrity ultrasonic testing and during ultrasonic measurements of the weld adjacent zone grain size value following the weld repair.
- Trofimov M.A., Globa R.A. Investigation of the dependence of acoustic echo signal on the average grain size in a welded joint. Eurasian Scientific Association. 2015, v. 1, no. 10 (10), pp. 54-57 (in Russian).
- Trofimov M.A., Globa R.A. Measurement of the average grain size in the welded joint of the feed line of the reactor installation. Tyazhyoloye Mashinostroyeniye. 2014, no. 11-12, pp. 28-31 (in Russian).
- Trofimov M.A., Globa R.A. Technique for ultrasonic testing of a two-component metal reactor system VK-50. Izvestia Vysshikh Uchebnykh Zawedeniy. Yadernaya Energetika. 2012, no. 3, p. 32 (inRussian).
- GOST 2789-73 Surface Roughness. Parameters and Characteristics. Available at: https://internet-law.ru/gosts/gost/1419/ (accessed Apr 04, 2019) (in Russian).
- Bakumenko V.I., Bondarenko V.A., Kosorukov S.N., Atminis S.A., Bersenev Yu.V., Vorontsov Yu.P., Komarov V.I., Kudryavtsev A.V., Lavrov L.P., Mikhalev O.R., Netsvetaev S.A., Paveliev V.I., Svalov G.F., Svechnikov V.B., Tinnikov O.N., Finashin V.N. Quick Reference for Designer of Non/Standard Equipment. In 2 volumes. Vol. 1. Moscow. Mashinostroenie Publ., 1997, 544 p. (in Russian).
- Demkin N.B., Ryzhov E.V. Surface Quality and Contact Details of Machines. Moscow. Mashinostroenie Publ., 1981, 244 p. (in Russian).
- Popov S.A. Grinding Work. Tutorial. Moscow. Vysshaya Shkola Publ., 1987, 383 p. (in Russian).
- Krautkremer Y., Krautkremer G. Ultrasonic Control of Materials. Moscow. Metallurgiya Publ., 1991, 673 p. (in Russian).
- Scherbinsky V.G. Technology of Ultrasonic Testing of Welded Joints. Moscow. Tissot Publ., 2005. 326 p. (inRussian)
- Kretov E.F. Ultrasonic Flaw Detection in Power Engineering. St. Petersburg. Radioavionika Publ., 1995, 317 p. (in Russian).
- GOST 5639-82. Steel and Alloys. Methods of Detection and Determination of Grain Size. Available at: https://internet-law.ru/gosts/gost/30103/ (accessed Apr 04, 2019) (in Russian)
- GOST R ISO 4287-2014. Geometric Characteristics of Products (GPS). Surface Structure Profile Method. Terms, Definitions and Parameters of Surface Structure. Available at: https://internet-law.ru/gosts/gost/58916/ (accessed Apr 04, 2019) (in Russian)
- Saltykov S. А. Stereometric Metallography. Moscow. Metallurgiya Publ., 1976, 271 p. (in Russian).
- Gulyaev A.P. Metal Science. Textbook for universities. 6th edition. Moscow. Metallurgiya Publ., 1986, 544 p. (in Russian).
- Van Der Voort G.F. Metallography: Principles and Practice. ASM International, 1999, 437 p.
- Muravev V.V., Muraveva O.V., Bayteryakov A.V. Method of determining the acoustic structural noise of a metal. Intellectual’nye systemy v proizvodstve. 2013, no. 1, pp. 143-148 (inRussian).
- Chernyavsky K.S. Stereology in Metallurgy. Moscow. Metallurgiya Publ., 1977, 208 p. (in Russian).
- Anurev V.I. Designer’s Handbook – Mechanical Builder. In 3 volumes, 8-th ed., revised and extended. Moscow. Mashinostroenie Publ., 2001 (in Russian).