![]() Thermal spectra calculated with two distinct fission yield libraries (corrected ENDF/B and JEFF) differ by up to 6% in the 0–7 MeV energy window, allowing for a basic estimate of the uncertainty involved in the fission yield component of summation calculations. An anomalous value for the thermal fission yield of 86Ge generates an excess of antineutrinosmore » at 5–7 MeV, a feature which is no longer present when the corrected yields are used. These corrected yields are used to calculate antineutrino spectra using the summation method. Following a critical review of the thermal and fast ENDF/B-VII.1 235 U fission yields, deficiencies are identified and improved yields are obtained, based on corrections of erroneous yields, consistency between decay and fission yield data, and updated isomeric ratios. D.įission yields form an integral part of the prediction of antineutrino spectra generated by nuclear reactors, but little attention has been paid to the quality and reliability of the data used in current calculations. The number of fission products of each species were measured by gamma spectrometry of co-located thick deposits.Įffects of fission yield data in the calculation of antineutrino spectra for U 235 ( n, fission ) at thermal and fast neutron energies Fissions were counted in thin deposits using fission ionization chambers. ![]() Irradiations were performed at the E元 reactor, at the Caliban and Prospero critical assemblies, and at the Lancelot electrostatic accelerator in CEA-Valduc. The yields of more than fifteen fission products have been carefully measured using radiochemical techniques, for 235 U(n,f), 239Pu(n,f) in a thermal spectrum, for 233 U(n,f), 235 U(n,f), and 239Pu(n,f) reactions in a fission neutron spectrum, and for 233 U(n,f), 235 U(n,f), 238 U(n,f), and 239Pu(n,f) for 14.7 MeV monoenergetic neutrons. Fission Product Yields of 233 U, 235 U, 238 U and 239Pu in Fields of Thermal Neutrons, Fission Neutrons and 14.7-MeV Neutrons ![]()
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