Leak detection in nuclear piping outside containment

The results of an experimental investigation performed at Wyle Laboratories to evaluate various methods for detecting small leaks in high energy piping systems is described. These experiments were designed to support the leak-before-break methodology currently being employed by the United States nuclear industry. This methodology requires that: 1. the flow rate through a hypothetical leak be accurately predicted, and 2. the lower limits of detecting the flow rate through such a leak be established. The research described in this work was designed to establish experimentally this limit of detectability. The experiments performed covered a range of leakage flow rates between 0.1 and 5 gpm (378-18925 cm3/min through small penetrations in a 6-in. diameter carbon steel pipe. Insulation, typical of the types found in nuclear power plants, covered the test pipe. The key observation made is that leak rates down to 0.1 gpm (378 cm3/min) are easily detectable. (orig.)