Experimental study of coaxial cable noise mechanism on ion chamber measurement line for PHWR

In this paper, the coaxial cable noise generated by bending or mechanical stress has been studied to find out the root cause of PHWR(Pressurized Heavy Water Reactor) trips at low power. The coaxial cable causes triboelectric noise from bending or vibration, and piezoelectric noise from dielectric characteristics of cable insulator. From measured cable noise results in the laboratory test and plant site test, the coaxial cable noise is estimated as a main factor that causes unpredictable reactor trip.