It is asserted that neutron become stable within an nucleus. But is that assertion necessary for "stablity"? What if it is a dynamic stability? If the protons array themselves on the outward surface of the nucleus (as repulsion would demand), with the neutrons on the inside, then when one of the neutron starts to decay, as we know they a wont to do, there is a very good chance that the electron-neutrino will be captured by one of the protons before escaping the nucleus. This leaves a neutron on the surface and a proton in the interioir. But the "negative hole" in the proton surface will strongly attract the interior proton, returning things to normal.