FEM evaluation for integrity on damaged stud female threads with pressure vessel according to ASME code

It should be evaluated and compared by ASME code criterion for integrity evaluation of stud bolts on nuclear power plant. According to the results, the procedure of code case-496 has to be applied to damaged female threads for maintenance. It is following to manufacture recommendation criterion for female threads which is damaged over 10% on thermal power plant until now generally. For ASME code of nuclear power plant, it has been done analysis by condition of imaginary damaged female threads of the stud 'until three threads(10%)' using FEM under the same model and condition. From analysis results, we found that it need repair when damaged female threads is over 10% same as recommendation. It was also re-confirmed to safety for Heli Coil method using FEM. The final purpose is to predict and ensure integrity for male · female threads after Heli Coil maintenance according to ASME code