Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
권호 표지
DOI QR코드

DOI QR Code

A STUDY ON THE AGING DEGRADATION OF ETHYLENE-PROPYLENE-DIENE MONOMER (EPDM) UNDER LOCA CONDITION

  • Seo, Yong-Dae (Department of Nuclear Engineering, Hanyang University) ;
  • Lee, Hyun-Seon (Department of Nuclear Engineering, Hanyang University) ;
  • Kim, Yong-Soo (Department of Nuclear Engineering, Hanyang University) ;
  • Song, Chi-Sung (Korea Institute of Machinery and Materials)
  • Received : 2010.10.01
  • Accepted : 2011.03.03
  • Published : 2011.06.25
Download PDF
⟨ Previous Next ⟩

Abstract

The aging degradation and lifetime assessment of a domestic class 1E Ethylene-Propylene-Diene-Monomer (EPDM), which is a popular insulating elastomer for electrical cables in the nuclear power plants, were studied for equipment qualification verification under the Loss of Coolant Accident (LOCA) conditions. The specimens were acceleratively aged, underwent a LOCA environment, as well as tested mechanically, thermo-gravimetrically, and spectroscopically according to the American Society of the Testing of Materials (ASTM) procedures. The tensile test results revealed that the elongation at break gradually decreased with an increasing aging temperature. The lifetime of EPDM aged isothermally at $140^{\circ}C$ was 1,316 hours and reduced to 1,120 hours after experiencing the severe accident test. The activation energies of the elongation reduction were $1.10{\pm}0.196$ eV and $0.93{\pm}0.191$ eV before and after the LOCA condition, respectively. The TGA test results also showed that the activation energy of the aging decomposition decreased from 1.35 eV to 1.02 eV after undergoing the LOCA environment. Although the mechanical property changes were discernibly observed during the aging process, along with the LOCA simulation, the FT-IR analysis showed that the spectroscopic peaks and their intensities did not alter significantly. Therefore, it can be concluded that the degradation of the domestic class 1E EPDM due to aging can be tolerable, even in severe accident conditions such as LOCA, and thus it qualifies as a suitable insulating material for electrical cables in the nuclear power plants.

Keywords

References

  1. V. M. Moreno, R. S. Gorur, "Effect of Long-term Corona on Non-ceramic Outdoor Insulator Housing Materials," IEEE Transactions on Dielectrics and Electrical Insulation, 8, 117 (2001). https://doi.org/10.1109/94.910434
  2. Indian Rubber Institute, "Rubber Engineering," p. 486, McGraw-Hill, New York (2000).
  3. R. S. Gorur, S. S. Rajan, O. G. Amburgey, "Contamination Performance of Polymeric Insulating Materials Used for Outdoor Insulation Applications," IEEE Transactions on Electrical Insulation, 24, 713 (1989). https://doi.org/10.1109/14.34207
  4. IEEE Standard 383-1974, "IEEE Standard for Type test of Class 1E Electric Cable, Field Splices, and Connections for Nuclear Power Generating Station," IEEE, (1974).
  5. Y. Li, Y. Zhang, Y. X. Zhang, "Structure and Mechanical properties of SRP/HDPE/POE (EPR or EPDM) composites," Polymer Testing, 22, 859 (2003). https://doi.org/10.1016/S0142-9418(03)00022-9
  6. M. Giurginca, T. Zaharescu, A. Meghea, "Degradation of ethylene-propylene elastomers in the presence of ozone," Polym. Degrad. Stab., 50, 45 (1995). https://doi.org/10.1016/0141-3910(95)00108-X
  7. M. Ginic-Markovic, N. R. Choudhury, M. Dimopoulos, J. G.. Matisons, "Weatherability of coated EPDM rubber compound by controlled UV irradiation," Polym. Degrad. Stab., 68, 157 (2000).
  8. J. Li, S. Guo, X. Li, "Degradation kinetics of polystylene and EPDM melts under ultrasonic irradiation," Polym. Degrad. Stab., 89, 6 (2005). https://doi.org/10.1016/j.polymdegradstab.2004.12.017
  9. F. Delor-Jsetin, J. Lacoste, N. Barrois-Oudin, C. Cardinet, J. Lemaire, "Photo-, thermal and natural ageing of ethylene-propylene-diene monomer (EPDM) rubber used in automotive applications. Influence of carbon black, crosslinking and stabilizing agents," Polym. Degrad. Stab., 67, 469 (2000). https://doi.org/10.1016/S0141-3910(99)00147-0
  10. T. Zaharescu, R. Vilcu C. Podina, "Some Kinetics and Thermodynamic Aspects of Thermal Degradation of Lightly Stabilised Elastomers," Polymer Testing, 17, 587 (1998). https://doi.org/10.1016/S0142-9418(98)00002-6
  11. T. Zaharescu, C. Podina, D. Wurm, "Effect of Metallic Oxides on Thermal Stability of Ethylene-Propylene Terpolymer," J. Appl. Polym. Sci., 82, 2155 (2001). https://doi.org/10.1002/app.2062
  12. G.. Boiteux, J. F. Chailan, J. Chauchard, G.. Seytre, "Dielectric and mechanical spectroscopies for the study of thermal and radiochemical ageing of polymes," Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, 131, 172 (1997). https://doi.org/10.1016/S0168-583X(97)00198-5
  13. C. D. Gamlin, N. K. Dutta, N. R. Choudhury, "Mechanism and kinetics of the isothermal thermodegradation of ethylene-propylene-diene (EPDM) elastomers," Polym. Degrad. Stab., 80, 525 (2003). https://doi.org/10.1016/S0141-3910(03)00036-3
  14. ASTM, "Vulcanized Rubber and Thermoplastic Elastomers- Tension," ASTM D 412, (1998)
  15. ASTM, "Standard Test Method for Decomposition Kinetics by Thermogravimetry," ASTM Designation: E 164, (2004).
  16. D. G. Cain, "A Review of Equipment Aging Theory and Technology", NP-1558, EPRI, (1980)
  17. Hyung Won Lee, Yung Hee Kang and Jae Hee Kim, "Analysis of Post-LOCA pH for Korea Nuclear Units", Journal of the Korean Nuclear Society, 15, pp. 179-187, (1983)
  18. NRC, "Standard review plan", NUREG-75/087, US NRC, pp. 15.6.5-10, (1980)
  19. B. Bartonicek et al, "Life-assessment Technique for Nuclear Power Plant Cables," Radiat. Phys. Chem., 52, 639 (1998). https://doi.org/10.1016/S0969-806X(98)00172-8
  20. D. J. Carlsson, D. M. Wiles, "Degradation. In Encyclopedia of Polymer Science and Technology", 4, 2nd edn., p. 630, John Wiley (1986).
  21. R. L. Clough, K. T. Gillen, "Polymer Degradation and Stabilization," In ACS Symposium Series, Vol. 280, ed. P. P. Klemchuk, ACS, Washington D. C., 411 (1984).
  22. C. Gamlin, N. Dutta, N. R. Choudhury, D. Kehoe, J. Matisons, "Influence of eyhylene-propylene ratio on the thermal degradation behaviour of EPDM elastomers," Thermochimica acta, 367-368, 185 (2001). https://doi.org/10.1016/S0040-6031(00)00668-7
  23. Y. S. Cho et al, "Thermal Degradation Kinetics of PE by the Kissinger Equation," Material Chemistry and Physics, 52, 94 (1998). https://doi.org/10.1016/S0254-0584(98)80013-8
  24. R. Setnescu et al, "Chemiluminescence Study on the Oxidation of Several Polyolefins: I. Thermal-induced Degradation of Additves Free Polyolefins," Polm. Degrd. Stabi., 60, 377 (1998). https://doi.org/10.1016/S0141-3910(97)00096-7
  25. K. Anandakumaran et al, "Condition Assessment of Cable Insulation System in Operating Nuclear Power Plants," IEEE Trans. On DEI., 6, 376 (1999). https://doi.org/10.1109/94.775626

Cited by

  1. Influence of Ageing on Sealability of Elastomeric O-Rings vol.373, pp.1, 2017, https://doi.org/10.1002/masy.201600157
  2. Preparation, characterization, thermal, and electrical properties of chlorinated ethylene propylene diene monomer/hydroxyapatite nanocomposites vol.39, pp.6, 2018, https://doi.org/10.1002/pc.24171
  3. Interplay between key variables of peroxide cured EPDM and evaluation of electromechanical efficiency for MV cables vol.135, pp.15, 2017, https://doi.org/10.1002/app.46139