7 psi blew the tail off JAL 123. 7 psi.
Even a small explosion (say 10 gallons of vaporized Kerosene) in the Center tank could make an explosion that overpresures the fuselage, causing the wingbox tank to rupture from the inside out, because that’s what it did.
Why didn’t the wings fall off? They had the Weight of the fuel and engines on them, keeping them from immediately folding up and with the fuselage pitching up from the nose falling off, it too was producing lift, so it went up with the wings (the 3000 ft “zoom climb”)
When the engines finally began to spool down a few seconds later, the plane went ballistic and began to break up completely on the way down, The wings DID come off.
So now the wing box WASN'T "blown to hell from the INSIDE" like you claimed before. If the wing box was indeed blown to hell from the inside there wouldn't be the structural integrity to maintain climbing flight. One or the other.
Now, explain the debris field that went 90 degrees to the right of the flight path.