Abstract
While the operating voltages for some instrument and control (I&C) cables can be greater than 4 kV to operate pumps, controls, and provide auxiliary power, the operating voltage for most I&C cables is near 600 V. Although the electrical stress is not nearly as high in the insulation of these cables, an ac withstand two and one-half times greater than the operating voltage after a simulated design basis exposure (DBE) has been used in environmental qualification (EQ) to determine the ability of an insulation to meet a 40-year lifetime at an operating voltage. While multiple cable lengths greater than 10 feet are needed to replicate this EQ, systematic measurement of the electrical insulation strength in harvested cable insulations can be beneficial to better understand the remaining useful life of the insulation. This understanding can only be realized through systematic comparison to some level of DBE, and electrical insulation strength measurement can provide a baseline for comparison with other mechanical, chemical, and electrical characterizations that have been utilized. Accelerated aging of two types of ethylene propylene rubber (EPR) insulations from harvested cables was carried out, and the electrical breakdown strength and indenter modulus for both insulations were determined. Results showed that degradation of electrical breakdown strength occurred in only one type of BIW insulation and that this degradation did track with that measured by indenter modulus. The methodology for using Weibull statistics for electrical breakdown strength relative to time to failure is discussed.
| Original language | English |
|---|---|
| Pages | 892-898 |
| Number of pages | 7 |
| State | Published - 2019 |
| Event | 19th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, EnvDeg 2019 - Boston, United States Duration: Aug 18 2019 → Aug 22 2019 |
Conference
| Conference | 19th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, EnvDeg 2019 |
|---|---|
| Country/Territory | United States |
| City | Boston |
| Period | 08/18/19 → 08/22/19 |
Funding
This work was supported by the US Department of Energy’s Office of Nuclear Energy Light Water Reactor and Sustainability program. This manuscript has been authored by UT-Battelle LLC under Contract No. DE-AC05-00OR22725 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). This manuscript has been authored by UT-Battelle LLC under Contract No. DE-AC05-00OR22725 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). This work was supported by the US Department of Energy’s Office of Nuclear Energy Light Water Reactor and Sustainability program.
| Funders | Funder number |
|---|---|
| DOE Public Access Plan | |
| Office of Nuclear Energy Light Water Reactor and Sustainability program | |
| United States Government | |
| U.S. Department of Energy | |
| UT-Battelle | DE-AC05-00OR22725 |