Izvestiya vuzov. Yadernaya Energetika

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

Influence of Operating Time on the Corrosion Rate in Single-Phase and Two-Phase Media

3/18/2021 2021 - #01 Nuclear power plants

Baranenko V.I. Gulina O.M. Salnikov N.L.

DOI: https://doi.org/10.26583/npe.2021.1.03

UDC: 621.311.25:621.039.620.193.1

Modern foreign computer codes forecast a linear increase in pipe wall thinning over time due to the process of flow-accelerated corrosion (FAC), i.e., erosion-corrosion wear (ECW). However, the linear time-thinning dependence and the corrosion rate constancy are not typical of the operating conditions of NPP pipelines. And the associated excessive conservatism of the residual lifetime estimates leads to increased economic costs of repeated monitoring. In the domestic software tools, EKI-02 and EKI-03, the effect of the operating time is taken into account by introducing an appropriate coefficient into the Chexal-Horowitz model based on the yield of corrosion products into the coolant. This reflects the fact that the ECW rate increases in the early years of operation, when the yield of iron compounds in the feed water is very high, and that this process slows down significantly over time. The analysis showed that this dependence is valid for nuclear power plants with various types of reactor facilities. However, improving operating conditions, carrying out preventive measures, refining the water chemistry, etc. can reduce the FAC intensity in the components of equipment and pipelines, and the use of the dependences once obtained may turn out to be too conservative. Based on a large number of repeated measurements as well as data from corrosion indicators, the authors show that the effect of time can be described by a certain function, the coefficients of which differ for different units, types of components and subsystems. This makes it possible to determine the ‘aging function’ according to the control data, and then use it in a targeted way for specific elements. It is shown that the conservatism of such estimates is significantly lower.

References

  1. Chexal B. et.al. Predicting corrosion damage with the CHECWORKS software package. Nucl. Eng. Inter. 1992, no. 12, pp. PP. 22-25.
  2. Henzel N., Egan D.L. Managing erosion/corrosion with the WATHEC code. Nucl. Eng. Inter. 1989, no. 5, pp. 18-20.
  3. Horowitz J., Smith D. Recommendation for an Effective Flow-Accelerated Corrosion Program (NSAC-202L-R4). EPRI/3002000563. Technical Report. Palo-Alto, Clf, USA. EPRI, 2013, 94 p.
  4. Chexal Bindi, Horowitz Jeffery, Bouchacourt Michel et al. Flow-Accelerated Corrosion in Power Plants. TR-106611-R1. EPRI Energy Conversion. Palo-Alto, Clf, USA. EPRI, 1998, 504 p.
  5. Chexal V.K., Horowitz J.S. Chexal-Horowitz Flow-Accelerated Corrosion Model-Parameter and Influences. Current Perspective of Inter. J. Pressure Vessels and Piping: Codes and Standard. Book No. 409768. ASME, 1995, pp. 231-243.
  6. Zander A. COMSY – A Software Tool for Aging and Plant Life Management. Proc. of the AREVA NP GmbH, PTCMT-G III-th Plant Life Management Conf. May 14-17, 2012. Salt Lake City, USA.
  7. Rodriguez I., Contino M. et al. Implementation of the COMSY Code in a PHWR NPP Analysis of Low Pressure Turbine Extraction Lines. Proc. of the Intern. Conference on FAC. May 21-24, 2013. Avignon, France. EDF, 15 p.
  8. Akimov G.V. Fundamentals of Teaching about Corrosion and Protection of Metals. Moscow. Fizmatgiz Publ., 1946, 461 p. (in Russian).
  9. ASME code Case N-480. Examination Requirements for Pipe Wall Thinning Due Single Phase Erosion and Сorrosion. Section XI, Division, pp. 787-795.
  10. Baranenko V.I., Gulina O.M., Dokukin D.A., Yanchenko Yu.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).
  11. Naftal’ M.M., Baranenko V.I., Gulina O.M. Use of software for calculation of erosion and corrosion wear of NPP equipment and pipelines. Teploenergetika. 2014, no. 6, pp. 1-8 (in Russian).
  12. Baranenko V.I., Prosvirnov A.A., Evropin S.V., Arefiev A.A., Yurmanov V.A., Gulina O.M. Development of software tools and regulatory documents for erosion-corrosion wear of pipelines at NPPs. Teploenergetika. 2012, no. 5, pp. 34-38 (in Russian).
  13. 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).
  14. 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).
  15. 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 NPPs based on control data. Izvestiya vuzov. Yadernaya Energetika. 2017, no. 4, pp.83-94; DOI: https://doi.org/10.26583/npe.2017.4.08 (in Russian).
  16. Baranenko V.I., Gulina O.M., Mironov S.A., Salnikov N.L. Repeated measurements and quality estimates in the analysis of erosion-corrosion wear of NPP pipelines. Izvestiya vuzov. Yadernaya Energetika. 2020, no. 3, pp. 17-29; DOI: https://doi.org/10.26583/npe.2020.3.02 (in Russian).

erosion-corrosion wear corrosion rate estimation pipeline wall thinning Chexal-Horowitz Flow-Accelerated Corrosion Model