An analysis of cladding failure on beam transient of lead-bismuth-cooled accelerator-driven system

The cladding failure analyses on various beam transients of Lead-Bismuth-cooled Accelerator-Driven System (ADS) were performed with ADSE code and the cladding failure analysis program. First, the cladding failure analysis program was developed. This program is intended for creep ruptures analysis using ADSE code and employs the method of Cumulative creep Damage Fraction (CDF) calculation. Beam diameter expansion, beam flattening, beam hollowing, and beam incident position change were analyzed for the ADS model proposed by JAEA. As a result, beam diameter expansion, beam flattening, and beam hollowing would not lead to cladding failures but beam incident position change was revealed to have a high risk for the cladding failures. Some core designs were proposed for the prevention of failure. The changes of sizes such as plenum length were not effective for CDF reductions. The application of SUS316FR steel cladding instead of Mod.9Cr-1Mo steel showed good performance but the application of SUS316FR steel needs some provisions for erosions and corrosions. The fuel composition change was very effective for CDF control and this measure would be the best modification for the prevention of cladding failures.