See the documentary. It covered that very well. Where the fuel tank ruptured is an important structual member of the aircraft frame. In the test they ran, this structual member was compromised. The aircraft did not blow apart, it basically ripped apart. This probably took up to three to five seconds as the nose section tilted upwards. This was consistent with the tears on the skin of the aircraft. I also had my doubts until I saw the documentary. The investigation was very well done.
Will fuel vapors explode???? Every see an FAE bomb go off? They had one in that airplane.
What was the fuel to air ratio in the tank? Do you really think it would support an explosive rapid burn? Remember it is essentially kerosene!