Study on the evaluation technology for dynamic destruction strength of components in a light water reactor

In the normal operation and transients of a light water power reactor, the structural components such as the pressure vessel and the primary loop piping suffer from various damages by neutrons, thermal aging, fatigue and dynamic loads. The evaluation methods applied for those effects up to now are based on the conservative assumptions. This research was carried out to improve those evaluation methods. For this purpose, three kinds of experiments were conducted. The first is the test of condensation-induced water hammer in which large loads as well as sharp pressure spikes exerting on the pipe line were measured, and the mechanism and the loads following a condensation-induced water hammer were made clear. The second is the dynamic loading test for structural materials and welding joints in which the dynamic strength and fracture toughness were investigated, and the evaluation method for those strength was discussed. In the third, an impact pressure testing machine was equipped and the strength properties of pressurized pipe were measured. (author)