Two kinds of assembly and welding methods of three-stage nuclear power project CV bottom head are introduced

compare and analyze the two methods from the demand amount for auxiliary fittings and the install removal mode

welding space and welding method

the amount of cutting

etc. The result shows that adopt the Backward Assembly of bottom head

the amount of bracket used for assembly will be reduced greatly

which will be help to remove and transport

and the amount of cutting is reduced

in addition with large welding space

which benefit to automatic welding. This paper also analyzes the stress shrinkage and deformation control of weld seam

hoisting and transportating mode

the advantages and disadvantages of the two assembly and welding methods are explored

so as to provide reference for the follow-up similar modules assembly and welding

convenient for the construction company to make full use of its advantages and choose the best assembling and welding method

which can reduce the workload on the basis of ensuring quality.