Methods for early defect detection and reduction of radiation exposure in periodic inspection and testing of safety-relevant pipework. Continuation of the tests with the potential drop method

Based on the good results obtained from the SR 2045 contract, the newly developed potential drop method was further examined for application in periodic inspections in nuclear facilities. Five installations in nuclear power plants - each tested for over about 1 year - confirm that the set up is suitable - if permantly installed - for continuous monitoring of indications found by NDT and locations particularly at risk. In addition, it can be used to replace ultrasonic and radiographic inspections. It has an advantage over these methods as the radiation exposure is lower and inspection results are more reliable. With a hand probe the method can be usefully applied to evaluate flaws for instance in austenitic steels what can be difficult for common NDT methods. Because of its advantages the method should be incorporated into the Nuclear Code. (orig.)