Effects of gamma irradiation on the degradation of silicone rubber by steam exposure

ABSTRACT Silicone rubber (SiR) is an important electrical insulating material for safety-related cables in nuclear power plants. This means that SiR must withstand the irradiation of gamma rays and the exposure to high-temperature steam. However, SiR is vulnerable to hydrolysis. Therefore, for the purpose of clarifying the behavior of SiR in such environments, sheets of SiR were exposed to steam at 171 or 200°C with and without pre-irradiation of gamma rays. As a result, it has become clear that SiR can withstand the exposure to high-temperature steam more robustly if it was irradiated by gamma rays to a proper dose in advance.

[1]  Y. Ohki,et al.  Degradation of Mechanical and Dielectric Properties of Flame‐Retardant Ethylene Propylene Rubber by Thermal Aging , 2020, IEEJ Transactions on Electrical and Electronic Engineering.

[2]  Y. Ohki,et al.  Comparison of the effects of heat and gamma irradiation on the degradation of cross‐linked polyethylene , 2019, IEEJ Transactions on Electrical and Electronic Engineering.

[3]  Y. Ohki,et al.  Degradation mechanisms of silicone rubber under different aging conditions , 2019, Polymer Degradation and Stability.

[4]  Y. Ohki,et al.  Insulation performance of safety-related cables for nuclear power plants under simulated severe accident conditions , 2017, 2017 International Symposium on Electrical Insulating Materials (ISEIM).

[5]  Yoshimichi Ohki,et al.  Dielectric and Carrier Transport Properties of Silicone Rubber Degraded by Gamma Irradiation , 2017, Polymers.

[6]  Liuqing Yang,et al.  Experimental investigation of the degradation mechanism of silicone rubber exposed to heat and gamma rays , 2017 .

[7]  Y. Ohki,et al.  Estimation of Talc Contents in Ethylene-Propylene-Diene Copolymer by Terahertz Absorption Spectroscopy , 2016 .

[8]  Y. Ohki,et al.  Space charge formation and charge transport in epoxy resin at varied temperatures , 2015 .

[9]  Y. Ohtake,et al.  Chemical Changes in Cross-linked Silicone Rubber by Ozone-water Treatments , 2014 .

[10]  Y. Ohki,et al.  Effect of tacticity on the dielectric properties of polystyrene , 2011 .

[11]  B. Patterson,et al.  Mössbauer, NMR and ATR-FTIR spectroscopic investigation of degradation in RTV siloxane foams , 2007 .

[12]  Y. Koshino,et al.  Method of Deterioration Diagnosis for Silicone Rubber Housing of Polymer Insulator (I): Pre-treatment Method of the Specimen and Selection of Analyzing Methods@@@試料の前処理法と各種分析技術 , 2000 .

[13]  S. K. Srivastava,et al.  Accelerated hydrothermal weathering of silicone rubber, EPDM, and their blends , 1994 .

[14]  R. Arhart.  The chemistry of ethylene propylene insulation. II , 1993, IEEE Electrical Insulation Magazine.

[15]  J. E. Mark,et al.  Characterization of PDMS model junctions and networks by solution and solid-state silicon-29 NMR spectroscopy , 1986 .

[16]  M. Ieda,et al.  Carrier transport in high-density polyethylene , 1979 .

[17]  R. Harris,et al.  29Si nuclear magnetic resonance studies of oligomeric and polymeric siloxanes: 4. Chemical shift effects of end-groups , 1978 .