Fission Product Yields from Fission Spectrum n+239Pu for ENDF/B-VII.1

Exploratory study of fission product yield determination from photofission of Pu239 at 11 MeV with monoenergetic photons

“…Very recently, this finding was confirmed by Gooden et al [5] using mono-energetic neutron beams, as opposed to the white neutrons of Refs. [1][2][3]. The data of Gooden et al [5] extended the positive slope to at least 5 MeV neutron energy.…”

“…The data presented for the highyield fission fragment 147 Nd in the neutron energy range between 0.2 and 1.9 MeV were evaluated by Chadwick et al [3] and Thompson et al [4]. They found an energy dependence for the 147 Nd FPY with positive slope of 3.7%/MeV and 3.2%/MeV, respectively.…”

Energy dependence of fission product yields from 235U, 238U, and 239Pu with monoenergetic neutrons between thermal and 14.8 MeV

“…The cumulative fission product yield of 147 Nd from 239 Pu is of particular interest due to a claimed energy dependence in data obtained from critical assemblies and fast reactors at low-energy (0.5 ≤ E n ≤ 2 MeV) [1]. The results obtained for this isotope are the strongest indication for energy dependencies in the fission product yields, as seen in Fig.…”

“…A primary motivation for the present work is to address issues raised [1][2][3][4] regarding possible energy dependencies of certain fission product yields. The paper by Chadwick et al [1] presented compelling evidence for a positive energy dependence for the fission product yield of 147 Nd from neutron induced fission of 239 Pu in the low-energy region between 0.2 and 2 MeV incident neutron energy as measured using critical assemblies and fast reactors. By using monoenergetic neutrons we are able to independently corroborate data extracted from these continuous, broad spectrum neutron sources.…”

“…In fact, in the design of modern reactors and advanced fuel cycles, accurate knowledge of the fission product yields as a function of incident neutron energy is crucial. Lastly, it was found that even though a number of measurements are available for the fission product yield of 147 Nd at 14 MeV [3], there are large discrepancies [1].…”