Abstract: Take the pipe whip analysis of main steam pipe and feed water pipes in AP1000 first bay as an example,the pipe layout is optimized to reduce the breaks and provide the necessary reference for the design of anti-whip limit.By deriving of the finite-difference theory based on energy balance and the dynamic analysis of the finite element,the methods for analyzing of the kinetic energy from the pipe whip is studied.Finally,the impacted structure is analyzed to decide if an anti-whip device shall be installed,and to demonstrate that the pipe whip will not cause unacceptable damage to the important structures such as the building of nuclear island.