3... Huge explosion with dark colors in the clouds leading one to believe that the actual core itself exploded.
Leading those who don't know the science to conclude that the actual core itself exploded.
Unit 3 suffered the same fate as Unit 1; a hydrogen explosion. However, Unit 3 had more time to accumulate more hydrogen before an explosion was triggered.
Reactor cores can't explode - that is they can't have the type of nuclear explosion one sees in a bomb. The fuel is too dilute; only 3-4% fissile material. Even in MOX, the percentage of plutonium is about 7%. One can not use a mixture that is <20% U-235 or <15% Pu-239 for bomb fuel. It's physically impossible to have such mixtures used for bomb fuel. In fact, the legal requirements for security change at the above levels so that less security is needed for material that can not be used to make a bomb.
Before the anti-nukes barrage with their misconceptions; mushroom clouds can happen with any explosion, not just nuclear. The fireball of the Unit 3 explosion was yellow, which meant it was not hot enough to emit greens, blues, and violets. Nuclear explosions emit frequencies all the way up to X-rays. Hence, in nuclear explosions, all visible colors are represented, and the fireballs are always white. The fact that Unit 3 is yellow is undeniable evidence that the explosion was chemical in nature.