Development of cores and fuels for BWRs

Toshiba has developed a zirconium liner fuel and high-performance cores for boiling water reactors (BWRs), in which high burn-up is economically achieved due to the advantages of the zirconium liner fuel. High burn-up Step-1 fuel, which was commercialized in 1987, achieves about 10% higher burn-up compared to conventional fuel with the same fuel assembly enrichment. Toshiba has also developed an improved multi-enrichment initial core which provides about 30% higher burn-up of initial fuel than a conventional initial core. High burn-up Step-2 fuel, commercialized in 1991, is designed to achieve a performance of about 39.5 GW·d/t in the reload core. Analytical methods to precisely evaluate the characteristics of cores and fuels have been developed as the basis for realizing these high-performance cores and fuels. (author)