Repeated measurements and quality of assessments in the ananlysis of NPP pipeline erosion-corrosion wear
The article describes a study carried out on carbon steel pipe elements subject to erosion-corrosion wear (ECW). Based on the repeated control data, the authors present the results of calculating the characteristics of the ECW: wall-thinning and ECW rate. It is shown that such estimates contain great uncertainty due to the deposits of corrosion products on the pipeline inner surface and their migration during operation. In addition, with an increase in the operating time, for example, when the lifetime is extended, the difference between the forecast and the results of control becomes larger. This means that the error in the estimates of the residual lifetime also increases. The study is based on the data of wall thickness measurements of the feed water pipe (273×16 mm) and steam pipe (465×16 mm) of nuclear power plants with VVER-440 reactors, for which a sufficient number of repeated measurements were performed over a large time interval. An analysis is made of the error in estimating the pipeline wall-thinning and ECW rate using Chexal-Horowitz Flow-Accelerated Corrosion (FAC) Model (ECW-02 and ECW-03 software tools). The estimate of the ECW rate according to the above forecast model differs from the estimate according to the current control data by no more than 12.5%, since the deposits of corrosion products on the pipeline inner surface wall are leveled at a large time base. When calculating the wall-thinning, due to the obvious filtering of the control data, it is possible to achieve an acceptable accuracy of estimates, i.e., about 16% without upgrading the model.
- Baranenko V.I., Gulina O.M., Salnikov N.L., Murzina O.E. Substatiation of FAC rate and service life estimation under operation control data. Izvestiya vuzov. Yadernaya Energetika, 2016, no. 2, pp.55-65 (in Russian).
- Bridgeman J., Shankar R. Erosion/corrosion data handling for reliable NDE. Nuclear Eng. And Design, 1991, v. 131, pp. 285-297.
- Lee S.H., Kim T.R., Jeon S.C., Hwang K.M. Thinned Pipe Management Program of Korean NPPs. Proc. of the XVII&th Intern. Conf. on Structure Mech. in Reactor Technology (SmiRT 17). Prague, Czech Republic. August 17-22, 2003, pp. 1-8.
- Moolayil T.M. Mitigation of degradation of high energy secondary cycle piping due to FAC and life management in Indian NPPs. Second International Symposium on Nuclear Power Plant Life Management from 15 & 18&th October, 2007 at Shanghai China. 48 p.
- Moolayil Т.М. On the issue of flow corrosion. Atomnaya Tekhnika za Rubezhom, 2008, no. 12, pp. 16-21 (in Russian).
- Baranenko V.I., Yanchenko Yu.A., Gulina O.M., Dokukin D.A. Estimation of erosion-corrosion wear rate and residual lifetime for NPP piping. Izvestia Vysshikh Uchebnykh Zawedeniy. Yadernaya Energetika, 2010, no. 2, pp. 55-63 (in Russian).
- ТU 14-3-460-75: Seamless steel pipes for steam boilers and pipelines. Moscow. CNIIAtominform, 1976, 87 p. (in Russian).
- Recommendation for an Effective Flow-Accelerated Corrosion Program (NSAC-202L-R4). EPRI/ 3002000563. Technical Report, November 2013. EPRI. 94 p.
- Baranenko V.I., Naftal’ M.M., Polyakh V.I. The effect of deposits of corrosion products on erosion-corrosion wear of pipelines at nuclear power plants. 2013: Brief results of scientific and technical activities of VNIIAES. Мoscow. VNIIAES Publ., 2014, pp. 154-161 (in Russian).
- Chexal Bindi, Horowitz Jeffery, Bouchacourt Michel et al. Flow-Accelerated Corrosion in Power Plants. TR-106611-R1. EPRI Energy Conversion. 1998. 504 р.
- Baranenko V.I., Gulina O.M., Salnikov N.L. Flow-accelerated corrosion rate and residual life time estimation for the components of pipeline systems at nuclear power plants based on control data. Izvestiya vuzov. Yadernaya Energetika, 2017, no. 4, pp. 83-94 (in Russian).
- Ruscak M., Kaplan J., Kadecka P. Complex Approach to the Lifetime Evaluation of WWER secondary Piping due to Erosion/Corrosion. Proc. of the IAEA Specialists Meeting on Erosion/ Corrosion of Nuclear Power Plant Components. – Russia, Vladimir. Sept. 13-16, 1996, pp. 24-30.
- Gulina O.M., Frolova O.O. Prediction of NPP equipment lifetime under the conditions of erosion-corrosion wear based on an empirical model. Izvestia Vysshikh Uchebnykh Zawedeniy. Yadernaya Energetika, 2012, no. 1, pp. 57-65 (in Russian).
- Guidance document RD EO 18.104.22.168.0571-2010. Norms of allowable thicknesses of pipelines elements made of carbon steel during erosion&corrosion wear. Мoscow. VNIIAES Publ., 2012, 104 p. (in Russian).
- Chexal V.K. (Bind), Horowitz J.S. Chexal-Horowitz Flow-Accelerated Corrosion Model-Parameter and Influences. Current perspective of Inter, Pressure vessels and Piping. Codes and Standard, Book No, 409768, 1995, pp. 231-243.
- Guidance document RD 27.28.05.061-2009 Guidelines for monitoring elements of equipment and pipelines of nuclear power plants subject to erosion and corrosion wear. Мoscow. VNIIAES Publ., 2010, 39 p.