Coupling device for the limited tubular space in the maintenance of nuclear power plants

Tomiyoshi, Kentaro; Ito, Fuyumi; Nishimura, Akihiko  

Careful inspection should be paid on aging nuclear power plants. Due to the Fukushima BWR accident, more advanced inspection techniques are now requested in Japan. To find SCC along welded sections by Ultrasonic Testing or Eddy Current Testing is difficult due to the low S/N. Here we propose to apply Magnetic particle Testing (MT) on the inspection. MT uses magnetic particles uniting fluorescent pigment. It is a weak point of MT that uniting particles and pigment is breakable. To extend the lifetime. We developed unique capsule for the magnetic particle to coexist with fluorescent pigment. In addition, MT using the micro capsules and related devices are presented.