There is little or no silver in film. It is 99.999+% Silver halide with some sulfides present and other silver salts. Any silver metal is there as a latent image if the film is exposed and that is quite resistant to oxidation. The latent image is in very low concentration and can fade with time as well.
I shield all of my film from Kryptonite radiation!
The Van Allen belt created by the magnetic field of the earth does a good job off keeping the sun's radiation away, but a poorer job with the higher energy of the cosmic background radiation. Much of the sun's radiation is in the form of neutrinos that go right through us and our film with no harm being done whatsoever.
The bottom line is that there is no easy way to preserve film from heat and radiation effects.