Application Of Leak-Before-Break (LBB) Analysis Technology In The Design Of Liquid Metal Cooled Fast Breeder Reactors(LMFBR) Pipeline

Based on the leak before break (LBB) analysis method, according to the requirements of French regulatory RCC-MR, this paper performs a fracture mechanics analysis on the intermediate loop of the decay heat removal system in China Experimental Fast Reactor(CEFR). Suppose that a throughwall defect had existed where the loads were most serious before the operation of the reactor, according to J-integral tearing modulus inter-section method, the critical length of crack in the worst condition (namely synthesized enveloped operation conditions) was obtained. With Paris formula the stability growth of the crack was calculated under alternate loads. The open area of the critical crack and the crack at the end of life were obtained by a mechanical model established by CASTEM2000 code.Through research and analysis, the conclusions are summarized as follows:The pipeline has the LBB characteristics, the assumption of DT / 4 (D means pipeline diameter, and T tube wall thickness) for the pipeline break size of fast reactor is safe for the design of the pipeline.