The images attached are taken during the cleanup at Chernobyl. The white "streaks" at the bottom of each picture are said to be from intense radiation striking the film negatives, which makes sense (that's how they were discovered after all).
Question: My main question is about the structure of those white streaks? Why are they perfectly vertical?
Guess: My guess is that they are due to the geometry of the camera's shutter, but I just don't know enough about cameras to assert this with confidence.