[Moonman62]

There is no guarantee, even, that the two particles have the same sign of charge, depending on which one gets more or less of the original fissioned atom's electrons.

The electrons play no significant role in nuclear (hence the term nuclear) fission. It is the splitting of the nucleus that matters, and all the resulting fragments are going to have positive charge.

[CarrotAndStick]

What about beta particles then? They have a negative charge!

[Wonder Warthog]

"The electrons play no significant role in nuclear (hence the term nuclear) fission. It is the splitting of the nucleus that matters, and all the resulting fragments are going to have positive charge."

No, and I never said they did. But as soon as those two positively charged nuclei form, they start grabbing electrons from whereever they can get them, including the ones floating around the individual atom. So, probably by the time they have reached their "first bounce", they may be either positively or negatively charged.

But all that aside--the electrostatic repulstion between even two all-positively charged is TINY compared to the energy imparted due to the mass difference. We're talking a few eletron volts vs MILLIONS of electron volts.