The paper considers the Coulomb capture of transit electrons in the potential wells of gaps with the aim of deriving conditions under which this process only slightly reduces the power gain factor Q. It shows that for a reactor system these conditions are theoretically possible if an artificial mechanism is established which would pump out the trapped electrons from the gaps at a fixed rate while exerting only a slight effect on the untrapped electrons. In this system, the depth of the gaps themselves must not exceed a few centimetres. However, even if these conditions are fulfilled, the effect of capture on Q has no good 'reserve of smallness' and so anomalous processes in the gaps prove to be dangerous for the reactor.