[en] The ''cold leg'' in a PWR is defined as that portion of the primary coolant loop that lays between the coolant pump and the reactor vessel. One of the conditions which may lead to failure in a cold leg consists of repeated cycles of stress. These repeated stress cycles may cause the growth of any small defect in the weld or base material and, if the stress cycles are high enough and frequent enough, the defect may grow until it penetrates the wall, resulting in a leak, or under some postulated conditions, a large break might occur. The objective of this report is to present an evaluation of available fatigue test data on piping products to determine the margin of safety of the present ASME code method of evaluation; to determine the leak-rupture trends of components tested with significant internal pressures; and to determine the implications of the tests with respect to the cold leg piping systems in PWR's