Chris is correct in that it is impossible for your scan to reveal any hint of grain if in fact the film received absolutely no exposure before normal development.
As Chris described, grained is form by the clumping together of silver halide crystals or color dyes as they react to light and are transformed into metallic silver and fixed dyes in the development process.
However, I am skeptical that what you are seeing is even the film at all. If it is then you would have had to scan it at an incredibly high resolution and enlargement. The gelatin or synthetic film base of modern films is quite fine and uniform.
I suspect what you are seeing has more to do with your scanner than the film base even though the film in question is Konica, a rather inferior specimen at best. They would have to be making their film base out of used shoe leather to get that kind of surface texture.
Peace! Sidney
