Double-bottom construction can prevent a sudden leak of the medium, but it is hard to locate the leakage without the disassembly of the inside bottom once the leakage in outer bottom occurs.
The leakage in the outer bottom requires the partial removal of the inside bottom.
On this basis, the position of a potential leakage was chosen in the outer bottom of the tank.
In the places indicated by AE testing, welding defects were found in welds of the outer bottom, which could be the reason of the leakage.
The legs angle out to the side about 110 degrees (which makes the outer tops of the legs 5-1/2" apart (the width of the top board), and the outer bottoms
of the legs about 24" apart.