Creep-fatigue test of an elbow subjected to cyclic in-plane moment loading

As for the design of the pipings of primary cooling system in power reactor facilities, it must be in accordance with the standards regarded as appropriate in view of the safety. As one of such standards, ''Technical standard for structures concerning power reactor facilities'', MITI Notification No. 501, can be named. But in the pipings of primary cooling system for the fast breeder reactor under development by the Power Reactor and Nuclear Fuel Development Corp., the metal temperature exceeds the temperature range applied in the above notification, therefore the authors have carried out tests and researches in order to establish the standard for the high temperature design of the pipings of primary cooling system. In the present study, the equation of composition regarding the elasto-plastic creep of the materials to be tested was assumed, and from the total strain values measured at the place of creep-fatigue fracture of tested elbows, stress, plastic strain, creep strain and so on were calculated taking the multi-axial property in consideration. On the basis of the results, creep-fatigue life was evaluated by respective methods of Campbell, Manson and Code Case 1592, and it was compared with the test data. Also the inelastic analysis under simplified loading cycles was carried out with the general purpose finite element analysis code, MARC. The testing apparatus and specimens, the progress of test and the results, the analysis on the basis of measured strain, the analysis by the finite element method, and the evaluation of creep-fatigue life are explained. (Kako, I.)