Observation of oxidized region in -ray irradiated polyethylene with KOH treatment and SEM-EDS

Shimada, Akihiko; Sugimoto, Masaki; Yoshikawa, Masahito

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 30, 2015/03

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2014-050.pdf#page=62

In case of the accelerated ageing test on polymer cable insulation used for the nuclear power facility, it is very important to recognize whether oxygen penetrates in the polymer wholly or not. To confirm this, there are the method by which polymer is soaked in the KOH solution at 70C for 5 minutes, dried and observed by a SEM-EDS, only for ethylene propylene rubber, one of the polymers. This study is to apply that method for polyethylene. Polyethylene sheet of 2 mm thickness was irradiated by ray at a dose rate of 2 kGy/h for 400 h. A piece of irradiated polyethylene was picked up and the piece was soaked in the KOH solution for 24 h. After that, the piece was observed by a SEM-EDS. At the region within 70 micro meters from the surface, potassium is observed. It means that oxidation is occurred in this region. From now on, optimum soaking time will be examined.