Water seeps into my concrete foundation walls after heavy rains. How can I seal from the inside?

No but you will try anyway, some things that will help, make sure that a flashing overlaps your gutter, so that the water doesn't go between the gutter and the roof, then finds it's way into your basement, keep gutters cleaned out and not leaking, have a downspout that effectively Carries the water away from the basement. You can seal away from the inside, and first little heave or move of the earth and the seal is gone. If you are only getting as little moisture as you indicate then if you did the things that I advised most probably you would not have a problem.