Research On The Methods Of Transportation And Lifting For Huge Nuclear Power Containment

With the swift development of economic society,industrial equipment is being continuously improved towards of enlargement,modularization and intellectualization with which large goods transportation and hoisting technology are rising along.This kind of large equipment which is fairly expensive in manufacturing is also the key to both industrial construction and national defense.There are a few factors that restrict its transportation and hoisting which are also of huge risks.Hence it is even more important than ever to figure out how to transport the equipment to a designated place safely and hoist it successfully.Nowadays,nuclear power ‘going out' has been raised by our government to a national strategy and so does developing nuclear power with safety and efficiency to its long term plan.For an instance of AP1000 nuclear power station which is being under construction,its containment shells to bear incidental pressure are separated into different modules for hoisting and instalment.These modules are asymmetrical due to the deviation of gravity center and geometric center line and moreover,transporting large scaled equipment like this is restricted by site condition.If lifting measures are taken inappropriately during hoisting or transporting,the internal stress and displacement will directly impact on the quality of welding.If things go serious,it will not be able to provide safety protection from accidents.This essay is based on the background of the construction of the AP1000 nuclear power plant,and also to study its large-scale eccentrically structural safety shell containment.The main research is as below:(1)Based on the study of transportation preparation condition,the influence of different number of dismantling and different demolition sequence on stress and deformation of containment cylinder is analyzed.By comparing and calculating each scheme,a more reasonable support demolition and vehicle entry plan is determined.(2)Several different transport scheme are designed aiming at the situation which transport vehicle station is limited by road width and therefore causes large deformation on cylinder cantilever side.The analysis compared the stress and displacement between eccentric structure safety shell itself.An optimal control scheme for the elastic deformation is achieved.Through the study on the deformation control,an improved design is raised as the most reasonable transportation equipment.(3)This paper studies the security shell for super large eccentric flexible module,which is difficult to control its deformation.There are high requirement to the lower edge deformation and height difference control due to the technical limit on hoisting assembly.This paper establishes a finite element model for barrel hoisting,calculates to compare the effect of different hoisting point locations and number of hoisting points to shell lower edge deformation and height difference,and ultimately determine the lifting scheme is the best.(4)Based on comprehensive consideration for the feasibility,economy and safety of the containment hoisting project,this essay compared different hoisting project and find out that: with the premise of precision requirement,the less hoisting points is set,the easier the construction work could be performed,but the higher the cost of steel wires are and worse the economic efficiency it will get.This conclusion provides a good reference for the application of hoisting project in the construction.