key is stuck with vehicle running on 1993 Chevrolet G Series Van (G20)

my key is stuck in the ignition with the car running. I have to pull power fuse and disconnect battery to turn off. I can start it by reconnecting everything but i need it fixed please help

It sounds like the mechanical part of the ignition switch has failed. If after you place the transmission in Park you cannot rotate the key to the off position and with draw the ignition key the lock and tumbler assembly must have failed. I know you have to turn off the engine but disconnection the battery with the engine running can damage the alternator. I am not sure which fuse you are taking out perhaps it does disrupt power to the excite side of the alternator.
Have you tried spraying WD40 into the ignition lock as you try to rock the key back and forth/ in and out?