We have carbonate vessel at our urea plant with 304m3 capapcity and 4500mm dia (11mm thk+ 3mm clad). It is in service since 1980. The vessel imploded in the year 2003 due to some external pressure during shut down. The vessel was kept in service by applying pneumetic and hudraulic pressure after performing the hydrotest.

Now we want to perform the life assesment of the vessel as per API-579.
There are two options.
Option1: As per requirement of FFS assessement, detailed stress level and detailed distribution in the vessel would be done. This can be evaluated by performing filed measurements. All the data will b used in the calcualtion performed in the level 3 of FFS API 579 procedure.

Option 2: FE simulation will be performed to estimate the more detailed stress levels that the vessel experinced under operating load taking into account the dimensional changes and profile recorded during the inspection.

Can any one advice which option is more accurate and directive.

Good and new adeas will be apprecited.

Regards

Ikram