P4 Irradiation performance assessment of coated particle fuels using the IMGA system

The Irradiated-Microsphere Gamma Analyzer System (IMGA) provides the capability of making statistically accurate measurements of failed particle fractions on irradiated HTGR fuels /1/. Failure fraction is that fraction of fuel which has lost a significant amount of its fission products through defective coatings. IMGA is a fully automated system using high resolution gamma spectrometry coupled to a remote particle handler. The examination is non-destructive as it does not alter fission product inventory or distribution. Performance decisions are based on the sensitivity of a particle's retention capability to fission product volatility. Final failure fraction determination is based on the examination of a large population.