Fundamental study on the integrity assessment of LMFBR structures (III)

not registered

This report describes the results of "FundamentaI Research on Structural Integrity Assessment of Fast Breeder Reactor-1" which has been conducted by FCC II Subcommittee of Nuclear Engineering Research Committee, the Japan Welding Engineering Society under the contract with Power Reactor and Nuclear Fuel Development Corporation in a fiscal year of 1988. This project corresponds to a Phase-II study intending to extend the results obtained in "Study on Fatigue Crack Propagation Property of Fast Reactor Structural Materials" conducted during 1988-1986 fiscal years, to an establishment of a practical evaluation procedure for structural integriy assessment of fast reactor components. It is the purpose of present project to ensure that a creep-fatigue crack propagation property obtained with test specimens of simple geometry is applicable to the actual FBR components with more complex geometries under complicated loading conditions. For this purpose, a preparatory activity was made with simplified models simulating mechanical and geometric features of FBR components to attain accurate determination of crack propagation behaviors and accurate/efficient computation of J and J' integrals in actual FBR components. The study was made with following cases of modeling. (1)Finite plate with a surface crack under membrane and bending loading. (2)Finite plate with a through wall crack at a structural discontinuity under membrane loading. (3)Pipe with a surface crack under bending loading. (4)Elbow with cracks under bending loading. During fiscal year 1987, each of above models, made of type 304 stainless steel, were subjected to the completely reversed cyclic load at 850C to study the fatigue crack propagation behaviors. The electrical potential drop method for determining the size of surface crack was studied. The inelastic analysis was performed to evaluate the J and J' integrals of each types of the models. Furthermore, a literature survey was made for the ...