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Title: Advanced Models for Nondestructive Evaluation of Aging Nuclear Power Plant Cables

Abstract

Background: Nuclear power plant (NPP) cables must function correctly for proper power supply and control of the nuclear reactor. This is especially important for public and environmental safety at critical times such as during reactor shut-down following loss of coolant. Over extended periods of service, the cable insulation and jacket polymer materials suffer from degradation due to exposure to environmental stressors such as heat and ionizing radiation. The focus of this project has been the development of detailed descriptions of the way in which insulation polymers degrade, from a materials science perspective, and the development of new electrical techniques to monitor cable polymer condition nondestructively. Objectives: The objectives of this project have been to i) perform detailed characterization experiments upon cable insulation polymers that have experienced thermal and radiation exposure mimicking that received during NPP operation, including the exploration of novel cable nondestructive evaluation methods; capacitive, THz and infrared methods; ii) identify the most sensitive indicators of aging in these materials, and iii) develop advanced, validated models describing microstructural and chemical changes that are observed in cable insulation polymers due to thermal and radiation exposure. Methods: Accelerated aging was performed on the two most common United States NPP cable insulationmore » polymers (cross-linked polyethylene (XLPE) and ethylene propylene rubber (EPR)) under various conditions of elevated temperature and gamma radiation dose. Aging mechanisms were elucidated through extensive thermal, mechanical and microscopic characterization of the aged samples, and materials modeling. Dielectric and IR spectra were measured on pristine and aged samples. Data was analyzed statistically, via multiple linear regression, partial least squares and probabilistic neural network approaches. Impact: Extant cable monitoring techniques do not deal successfully with all polymer types. This research has laid a foundation upon which new electrical nondestructive test methods for cable polymer condition monitoring may be developed, hence launching the development of new test methods for cable insulation monitoring based on measuring electrical rather than mechanical parameters. Collaboration: This project has benefitted from collaboration between experts in materials science and engineering, materials modeling, electrical engineering, and nondestructive evaluation. The majority of the characterization measurements were carried out at Iowa State University. Materials modeling was carried out primarily at Washington State University. Irradiation of samples took place at Pacific Northwest National Laboratory (PNNL), where a student intern from Iowa State was hosted for one summer, setting up the aging experiments. A research student from the University of Bologna, Italy, joined the project for their thesis research at Iowa State University with samples provided by PNNL. The project benefitted from regular involvement of senior engineers in US-based industry partners. Project investigators presented findings at various national and international conferences and workshops.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [2];  [2];  [2]
  1. Iowa State Univ., Ames, IA (United States)
  2. Washington State Univ., Pullman, WA (United States)
Publication Date:
Research Org.:
Iowa State Univ., Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
1463136
Report Number(s):
DOE/NEUP-14-6863
14-6863; TRN: US1902728
DOE Contract Number:  
NE0008269
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; POLYETHYLENES; NUCLEAR POWER PLANTS; RUBBERS; DIELECTRIC MATERIALS

Citation Formats

Bowler, Nicola, Chiou, Chien-Ping, Liu, Shuaishuai, De Silva, Chamila, Shao, Zhihui, Guo, Ying- Bin, Gjersvik, Adam, Byler, Michael I., Beckman, Scott, Xu, Bo Z., and Sargin, Irmak. Advanced Models for Nondestructive Evaluation of Aging Nuclear Power Plant Cables. United States: N. p., 2018. Web. doi:10.2172/1463136.
Bowler, Nicola, Chiou, Chien-Ping, Liu, Shuaishuai, De Silva, Chamila, Shao, Zhihui, Guo, Ying- Bin, Gjersvik, Adam, Byler, Michael I., Beckman, Scott, Xu, Bo Z., & Sargin, Irmak. Advanced Models for Nondestructive Evaluation of Aging Nuclear Power Plant Cables. United States. https://doi.org/10.2172/1463136
Bowler, Nicola, Chiou, Chien-Ping, Liu, Shuaishuai, De Silva, Chamila, Shao, Zhihui, Guo, Ying- Bin, Gjersvik, Adam, Byler, Michael I., Beckman, Scott, Xu, Bo Z., and Sargin, Irmak. Sat . "Advanced Models for Nondestructive Evaluation of Aging Nuclear Power Plant Cables". United States. https://doi.org/10.2172/1463136. https://www.osti.gov/servlets/purl/1463136.
@article{osti_1463136,
title = {Advanced Models for Nondestructive Evaluation of Aging Nuclear Power Plant Cables},
author = {Bowler, Nicola and Chiou, Chien-Ping and Liu, Shuaishuai and De Silva, Chamila and Shao, Zhihui and Guo, Ying- Bin and Gjersvik, Adam and Byler, Michael I. and Beckman, Scott and Xu, Bo Z. and Sargin, Irmak},
abstractNote = {Background: Nuclear power plant (NPP) cables must function correctly for proper power supply and control of the nuclear reactor. This is especially important for public and environmental safety at critical times such as during reactor shut-down following loss of coolant. Over extended periods of service, the cable insulation and jacket polymer materials suffer from degradation due to exposure to environmental stressors such as heat and ionizing radiation. The focus of this project has been the development of detailed descriptions of the way in which insulation polymers degrade, from a materials science perspective, and the development of new electrical techniques to monitor cable polymer condition nondestructively. Objectives: The objectives of this project have been to i) perform detailed characterization experiments upon cable insulation polymers that have experienced thermal and radiation exposure mimicking that received during NPP operation, including the exploration of novel cable nondestructive evaluation methods; capacitive, THz and infrared methods; ii) identify the most sensitive indicators of aging in these materials, and iii) develop advanced, validated models describing microstructural and chemical changes that are observed in cable insulation polymers due to thermal and radiation exposure. Methods: Accelerated aging was performed on the two most common United States NPP cable insulation polymers (cross-linked polyethylene (XLPE) and ethylene propylene rubber (EPR)) under various conditions of elevated temperature and gamma radiation dose. Aging mechanisms were elucidated through extensive thermal, mechanical and microscopic characterization of the aged samples, and materials modeling. Dielectric and IR spectra were measured on pristine and aged samples. Data was analyzed statistically, via multiple linear regression, partial least squares and probabilistic neural network approaches. Impact: Extant cable monitoring techniques do not deal successfully with all polymer types. This research has laid a foundation upon which new electrical nondestructive test methods for cable polymer condition monitoring may be developed, hence launching the development of new test methods for cable insulation monitoring based on measuring electrical rather than mechanical parameters. Collaboration: This project has benefitted from collaboration between experts in materials science and engineering, materials modeling, electrical engineering, and nondestructive evaluation. The majority of the characterization measurements were carried out at Iowa State University. Materials modeling was carried out primarily at Washington State University. Irradiation of samples took place at Pacific Northwest National Laboratory (PNNL), where a student intern from Iowa State was hosted for one summer, setting up the aging experiments. A research student from the University of Bologna, Italy, joined the project for their thesis research at Iowa State University with samples provided by PNNL. The project benefitted from regular involvement of senior engineers in US-based industry partners. Project investigators presented findings at various national and international conferences and workshops.},
doi = {10.2172/1463136},
url = {https://www.osti.gov/biblio/1463136}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {7}
}