What is the name of this prison film!!?

this has been bugging me for years and i still cannot find out what the film is so ok... what i remember is that its based in a prison in the future i think when the prisoners are brought in they have some kind of device put inside them (orally i think!?) like a tracker the prison has a perimeter set up that if the prisoners cross the line the device beeps and if they go to far out they explode! anyway a few try to escape and the place is controlled by robots and machines.. its really bugging me..does anyone know the film?? thanks