Translation of Technical Development on Burn-Up Credit for Spent LWR Fuels

Technical development on burn-up credit for spent LWR fuels had been performed at JAERI since
1990 under the contract with Science and Technology Agency of Japan entitled ‘Technical Development on
Criticality Safety Management for Spent LWR Fuels.’ Main purposes of this work are to obtain the
experimental data on criticality properties and isotopic compositions of spent LWR fuels and to verify burnup
and criticality calculation codes. In this work three major experiments of exponential experiments for
spent fuel assemblies to obtain criticality data, non-destructive gamma-ray measurement of spent fuel rods
for evaluating axial burn-up profiles, and destructive analyses of spent fuel samples for determining precise
burn-up and isotopic compositions were carried out. The measured data obtained were used for validating
calculation codes as well as an examination of criticality safety analyses. Details of the work are described
in this report.