Composition, decomposition and analysis of reactor antineutrino and electron spectra based on gross theory of β-decay and summation method

•We calculated the reactor lepton spectra fully based on nuclear theory successfully.•The present methodology is independent of and complementary to the summation calculations ever conducted on the the experimental decay data.•We made it clear what kinds of beta-transition types and nuclides are important to shape the lepton spectra. Important role of the odd(Z)-odd(N) nuclides is argued.•The reactor antineutrino problem provides a good incentive and testing-basis for improvement of the theory, especially for odd-odd nuclides.

We applied the gross theory of β-decay to compose and decompose the reactor electron and antineutrino spectra emitted from 235,238 U and 239,241 Pu by summing up all the contributions from a large number of decaying fission-products (FPs). We make it clear what kinds of transition types and FP nuclides are important to shape the lepton spectra. Important role of the odd(Z)-odd(N  ) nuclides is also argued from the view point of the gross theory of β-decay. After taking the ambiguity in the current data for fission yields and QβQβ-values into account, we suggested a possibility that the high-energy part of the widely referred electron-spectra by Schreckenbach et al. might be too low. Our calculation supports the old experiment at University of Illinois.