Cumulative fission yield measurements with 14.7 MeV neutrons on ²³⁸U*

Abstract

The fission yield data in 14 MeV energy neutron induced fission of 238U play an important role for decay heat calculation and for generation-IV reactor designs. In order to measure fission product yields of 238U induced by 14 MeV neutrons accurately, the cumulative yields of fission products ranging from 92Sr to 147Nd in 238U(n, f) with 14.7 MeV neutron have been determined using an off-line γ-ray spectrometric technique. The 14.7 MeV quasi-monoenergetic neutron beam was provided by K-400 D-T neutron generator at China Academy of Engineering Physics (CAEP). Fission products were measured by a low background high purity germanium gamma spectrometer. The neutron flux was obtained from 93Nb (n,2n)92mNb reaction, and the mean neutron energy was calculated by the cross-section ratios for the 90Zr(n,2n)89Zr and 93Nb(n,2n)92mNb reactions. With a series of corrections, high precision cumulative yield of 19 fission products were obtained. Our FPYs for 238U(n,f) reaction at 14.7 MeV were compared with the existing data at 14 MeV from Experimental Nuclear Reaction Data and Evaluated Nuclear Data, respectively. They are helpful to design of generation-IV reactor and the construction of evaluated fission yield database.