At the beginning of the uranium decay chain how do protons get created to go from thorium back to uranium, since the beta radiation that causes the two steps ejects two electrons – so where do the new protons come from to go from atomic weight 90 to 92?

Question

I’m trying to understand how early in the uranium decay chain protons appear to go from thorium -234 to protactinium-234 to uranium-234, since the beta radiation that causes the two transitions only eject electrons – so where do the new protons come from to go from atomic weight 90 to 92.  I can’t find an explanation anywhere on the internet