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Title: Progress in Characterizing Thermal Degradation of Ethylene-Propylene Rubber

Abstract

Ethylene-propylene rubber (EPR) is one of the two most common nuclear cable insulation materials. A large fraction of EPR-insulated cables in use in the nuclear industry were manufactured by The Okonite Company. Okoguard® is the name of the medium voltage thermoset EPR manufactured by The Okonite Company. Okoguard® has been produced with silane-treated clay filler and the characteristic pink color since the 1970’s. EPR is complex material that undergoes simultaneous reactions during thermal aging including oxidative and thermal cleavage and oxidative and thermal crosslinking. This reaction complexity makes precise EPR service life prediction from accelerated aging using approaches designed for single discreet reactions such as the Arrhenius approach problematic. Performance data and activation energies for EPR aged at conditions closer to service conditions will improve EPR lifetime prediction. In this report pink Okoguard® EPR insulation material has been thermally aged at elevated temperatures. A variety of characterization techniques have been employed to track material changes with aging. It was noted that EPR aged significant departure in aging behavior seemed to occur at accelerated aging temperatures between 140°C and 150°C at around 20 days of exposure. This may be due to alternative degradation mechanisms being accessed at this higher temperature andmore » reinforces the need to perform accelerated aging for Okoguard® EPR service life prediction at temperatures below 150°C.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1406831
Report Number(s):
PNNL-25713; M3LW-16OR0404014
830403000
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; cables; npp; epr; thermal; degradation; aging

Citation Formats

Fifield, Leonard S., Huang, Qian, Childers, Matthew I., Correa, Miguel, Shin, Yongsoon, and Zwoster, Andy. Progress in Characterizing Thermal Degradation of Ethylene-Propylene Rubber. United States: N. p., 2016. Web. doi:10.2172/1406831.
Fifield, Leonard S., Huang, Qian, Childers, Matthew I., Correa, Miguel, Shin, Yongsoon, & Zwoster, Andy. Progress in Characterizing Thermal Degradation of Ethylene-Propylene Rubber. United States. doi:10.2172/1406831.
Fifield, Leonard S., Huang, Qian, Childers, Matthew I., Correa, Miguel, Shin, Yongsoon, and Zwoster, Andy. Fri . "Progress in Characterizing Thermal Degradation of Ethylene-Propylene Rubber". United States. doi:10.2172/1406831. https://www.osti.gov/servlets/purl/1406831.
@article{osti_1406831,
title = {Progress in Characterizing Thermal Degradation of Ethylene-Propylene Rubber},
author = {Fifield, Leonard S. and Huang, Qian and Childers, Matthew I. and Correa, Miguel and Shin, Yongsoon and Zwoster, Andy},
abstractNote = {Ethylene-propylene rubber (EPR) is one of the two most common nuclear cable insulation materials. A large fraction of EPR-insulated cables in use in the nuclear industry were manufactured by The Okonite Company. Okoguard® is the name of the medium voltage thermoset EPR manufactured by The Okonite Company. Okoguard® has been produced with silane-treated clay filler and the characteristic pink color since the 1970’s. EPR is complex material that undergoes simultaneous reactions during thermal aging including oxidative and thermal cleavage and oxidative and thermal crosslinking. This reaction complexity makes precise EPR service life prediction from accelerated aging using approaches designed for single discreet reactions such as the Arrhenius approach problematic. Performance data and activation energies for EPR aged at conditions closer to service conditions will improve EPR lifetime prediction. In this report pink Okoguard® EPR insulation material has been thermally aged at elevated temperatures. A variety of characterization techniques have been employed to track material changes with aging. It was noted that EPR aged significant departure in aging behavior seemed to occur at accelerated aging temperatures between 140°C and 150°C at around 20 days of exposure. This may be due to alternative degradation mechanisms being accessed at this higher temperature and reinforces the need to perform accelerated aging for Okoguard® EPR service life prediction at temperatures below 150°C.},
doi = {10.2172/1406831},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Aug 26 00:00:00 EDT 2016},
month = {Fri Aug 26 00:00:00 EDT 2016}
}

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