what artifacts the "radiation" would manifest in my images.
Short answerProbably nothing noticeable
Long answerThe effect of radiation on film is similar to the effect of light. Except with the ability to more easily penetrate the container the film is in. Radiation in the situation you described would be ambient rather than directional. The effect should be simply a general degree of 'lightening' of the image with no particular streaking of any kind. However:
1) The
amount of this lightening effect is unlikely to be noticeable. Pictures of Hiroshima immediately after it was bombed don't look significantly different from other pictures of their time. Neither do pictures developed from film that been taken on long flights.
2) The overall effect would occur before, during, and after the film was used rather than merely when the picture was taken. Radiation will tend to penetrate containers to some extent. If your film sits in an area of high radiation for years, it will be receiving radiation all that time. If a roll of film exposed in such a manner were to be taken to an area of low radiation and used, it would likely be affected more than new film taken to an area of high radiation and used immediately.
3) The innermost portion of the roll of film will tend to receive less radiation than the outmost portions. For example,
here is a picture of film that has been run through an airport scanner. The inside vs outside portions of film received a visibly different amount of radiation. But again, the amount of this effect is unlikely to be noticeable in the case of background radiation sufficiently low that the people taking the pictures are not dead.
Practical answerThis is an art project, yes? If you're using analog film, experiment with
film acceleration. Soak the film in lemon juice, burn the edges of the developed picture, etc. A visibly pleasing effect would probably be preferable to a technically accurate effect that either goes unnoticed or makes it look bad.