1. if the control rods were removed from the reactor core , there would be uncontrolled chain reaction inside the nuclear reactor.
2. if the rods were all fully inserted into into the reactor core, the chain reaction would stop completely.
3. 1) The core would become extremely hot, melting the fuel rods and most of the internal structure.
2) The buildings would catch fire and a huge amount of radioactive waste would be released into the atmosphere.
3) The molten fuel would gather in the bottom of the reactor chamber until it reached critical mass, and it would then explode causing catastrophic damage and pollution.