  The non-perturbative effects of QED-vacuum reconstruction under influence of
a supercritical EM-source ($Z>Z_{cr,1}$) are considered in view of lepton
number conservation. The question is here that if the vacuum shells formation
and spontaneous positron emission, associated with discrete levels diving into
the lower continuum, exist in reality, then it by no means should be a signal
of new physics. The reason is that the emitted positrons carry away the lepton
number equal to $(-1)\times$their total number, and so the corresponding amount
of positive lepton number should be shared by VP-density, concentrated in
vacuum shells. In this case instead of integer lepton number of real particles
there should appear the lepton number VP-density. Otherwise either the lepton
number conservation in such processes must be broken, or the spontaneous
positron emission prohibited.
  The conditions, under which the emission of vacuum positrons can be
unambiguously detected on the nuclear conversion pairs background, are also
discussed.
