The Reactor Anomaly has been a source of great interest for the physics community in recent years(1).
The generally accepted Huber-Muller conversion model to calculate the antineutrino spectrum has
raised several questions about the related experimental results and the different approximations used.
Improved measurements of nuclear data of relevant isotopes plus the use of the Summation Calculation
method for the determination of β decay spectra brings an alternative way of calculation. Moreover,
critical calculations of β decay spectra using standard data bases' β feedings currently suffer the
problem of the Pandemonium Effect, which can be solved with the application of the Total Absorption
Gamma Spectroscopy (TAGS) method. Montecarlo tools, such as the use of a precise event generator
for simulations that takes into account: γ cascade branchings, β feedings, β spectra shapes, conversion
electrons and electron-positron pairs generation, are required to obtain reliable simulated β decay
spectra. These simulations are essential to compare experiments to detailed theoretical calculations to
determine trustworthy reactors' antineutrino spectra predictions. The development of such
computational tool and some advances of the collaboration's experiment of the measurement of
relevant beta decay spectra with telescopic detectors will be discussed in this presentation.