Development of advanced fuel for high burnup

Fuel burnup extension is required to improve nuclear economy and reduce spent fuel generation. Fuel cladding waterside corrosion, pellet-cladding interaction (PCI) and fuel rod internal pressure are concerned at higher burnup. Mitsubishi has developed an advanced fuel with zirconium based alloy cladding of higher corrosion resistance, a radial texture controlled cladding of higher PCI resistance and large grain pellets to decrease fission gas release, since the latter half of the 1980s. The superior behavior of these advanced design has been confirmed by a lot of out of pile and irradiation tests in experimental and commercial reactors. Fuel demonstration programs in a Spanish and a Japanese commercial PWR are underway to prove fuel integrity at higher burnup up to the final target burnup of 55 GWd/t. After confirming fuel integrity in these programs, the advanced fuel for high burnup will be introduced as practical use in Japanese PWR plants from 2002 on. (author)