Measurement of intra-cell thermal neutron flux distribution in plutonium fuel lattice; Experiments on 20.0 cm and 28.3 cm pitch lattice

not registered; not registered; not registered; not registered; Takemura, Morio*

Intra-cell thermal neutron flux distributions have been measured in plutonium fuel lattices at 20.0 cm and 28.3 cm pitch by means of dysprosium foil activation method. Enrichment of PuO in PuO-UO fuel is 0.54 wt%. The measurements on 28.3 cm pitch lattice were made using air or HO as coolant. Those on 20.0 cm pitch lattice were made only using HO. The measurement uncertainty of 2 % in the present experiment is almost the same as that in the previous experiments on plutonium lattices at 22.5 cm and 25.0 cm pitches. The dependence of thermal neutron flux distributions on lattice pitch were made clear by the results of present experiment and previously obtained 22.5 cm and 25.0 cm pitch experiment. The calculations by the code LAMP-DCA agree with the experiment better than those by the code NOAH-II.