Started this thread not to speculate on root causes of the explosion. Meanwhile awaiting the release of the official root cause report, please share your knowledge on:
1) Investigation proceedings - How is investigation being carried out? What are the duties of Plant engineers?
2) Repair plans...
Beside filling with water to check for leakage, did you test it to operating pressure after proper repair procedures? what "if" another human error occurs? any mitigating plans or design review conducted?
Does the Code (any Code) allow the owner to perform a spot x-ray on the shell to effectively reduce the required minimum thickness?
Why do you need X-ray for in-service tank? If thickness of shell plate is your concern then you should employ spot UT not RT. RT is only useful during construction...
BS EN 14015:2004
Specification for the design and manufacture of site built, vertical, cylindrical, flat-bottomed, above ground, welded, steel tanks for the storage of liquids at ambient temperature and above.
Are you talking about this code?
Agreed with IFRs
It was a bad idea to repair only the "internal annular plate". As an aftermath of the bad idea, you are now asking for solution to repair only the "external".
I would say, perform a thickness check on the shell (1st Course) periphery, particularly the HAZ, to determine your...
A forged cross is preferred. If you have to use the fabricated cross, you have to make sure the material does not get too brittle for your service. Check HAZ and make sure proper stress release was employed during fabrication.
