CRUD FLAKERS SCRAPED FROM FUEL CLADDING IN HIGH BURN-UP PWRS ANALYSED BY EPMA

摘要

CRUD (Chalk River Unidentified Deposit), radioactive corrosion products formed inside nuclear reactors, is a major problem in commercial power-producing nuclear reactors. It can be transported onto the reactor core by cooling water, where it can be deposited on the outside of the fuel pins. Zinc is added to the reactor coolant system of a PWR to reduce the ex-core radiation fields and mitigate primary stress corrosion cracking. A chemical analysis of crud with ICP-MS, including ICP-AES, is a well-known analysis tool. In addition, the use of a shielded EPMA can produce specific results. For example it allows the chemical composition and distribution of crud from the cladding to exterior parts to be determined with 0.3 μm step intervals. EPMA's element mapping capabilities also provide identification and distribution of specific elements at spatial resolutions superior to other analytical techniques. Furthermore, the quantitative analysis of crud, using a shielded EPMA, provides greater versatility than other analytical devices.