Background:The wear type defect is very common volumetric flaw in steam generator tube

which is most important aspect to affect strength of steam generator tube.Thus

a specific assessment method shall be formulated aiming to this thin-wall tube.Purpose: The aim is to establish a formula of remaining strength factor based on burst pressure experiment results of steam generator tube specimens

which is applicable to safety assessment of cylinderical tubing containing local wall thinning defect.Methods: Therefore

the burst pressure test was performed in order to calculate the remaining strength of steam generator tube containing local thinning wall.Concerning assessment methodology of local wall thinning of cylindrical tubing

several assessment methodologies of the structural integrity were recommended within the codes

such as China code of NB20013

BS7910

API579 and Janelle’s dissertation.In the recent year

the burst pressure experiment was carried out on cylindrical tubing with local wall thinning defect

and the methods mentioned above were used to calculate the burst pressure and compared with the experiment result.Results: However

the calculated burst pressure result does not always match well the experiments.In the case that defect depth by wall thickness is over than or equal 70%

the calculated burst pressure is far more than the experiment’s

thus this case is not conservative as far as safety concerned.Conclusions: Finally the modified RSF formula is developed on the basis of the experiment’s burst pressure

and which is most accurately applicable to the result of burst pressure experiment.