Method for detection of defective pipe in bundle - uses medium which flows through parallel pipes with pressure difference between inside and outside

摘要

The method has been developed with special reference to heat exchanger tubes in pressurised water reactors. Two ends of one of the pipes are closed by valves. After a time allowed for the pressure equalisation in case of a leak, an effort is made to open the valve, and the force necessary for it is compared with that when no leak is present. Force applied during this test is less than that necessary for valve opening when a leak is present, so that leaky pipes remain closed. The valves are connected to their driving shafts by a shear wire.