Neutronic experiments in a Li-Pb spherical assembly

As a series of neutronic experiments for fusion reactor blanket designs in a Japanese inter-university research program using a lithium (Li) sphere of 120cm diameter and the intense D-T neutron source facility OKTAVIAN, several measurements on tritium breeding have been made in a complex assembly with neutron multiplying zone of lead(Pb) inside the Li sphere. Two experimental results in the assembly on leakage neutron spectra by a time-of-flight (TOF) technique and tritium production rate distributions by a liquid scintillation counting method using lithium carbonates (Li2CO3) pellets with foil activation rates are presented. Through comparison with calculations, there are discussed on the neutron multiplying and spectral shift effects due to the Pb layer and the present accuracy of the nuclear data of Li and Pb to improve the prediction of tritium breeding ratio (TBR). (author)